Programmer for an implantable cardiac stimulating device

This invention provides a therapy decision support system and method for guiding physicians and medical technicians in optimizing a set of adjustable parameters that define the operating characteristics of implantable cardiac stimulating devices. The invention also provides an implantable cardiac stimulating device programmer which can furnish therapy decision support as well as telemetric data retrieval and telemetric programming capabilities.

BACKGROUND OF THE INVENTION 
This invention relates to implantable cardiac stimulating devices, and in 
particular to a programing system for implantable cardiac stimulating 
devices. More particularly, this invention provides a therapy decision 
support system and method that allows physicians and clinical technicians 
to optimize a set of adjustable parameters that define the operating 
characteristics of implantable cardiac stimulating devices. 
Implantable cardiac stimulating devices are designed to treat cardiac 
pathologies known collectively as arrhythmias. The term "arrhythmia" 
refers to the failure of cardiac tissue to contract and relax in a 
regular, rhythmic fashion. There are two variables that generally define 
an arrythmia--heart rate and heart beat regularity. For example, if a 
heart beats at a regular but slower than normal rate, the arrhythmia is 
referred to as "bradycardia". A regular but faster than normal heart rate 
is referred to as "tachycardia". Finally, chaotic cardiac activity is 
known as "fibrillation". 
The purpose of an implantable cardiac stimulating device is to detect and 
terminate cardiac arrhythmias in a patient. Typically, this is 
accomplished by monitoring cardiac activity (e.g., the intracardiac 
electrogram, or "IEGM") of a patient through various sensors, and by 
delivering therapeutic electrical stimulation whenever an arrhythmia is 
detected. As different arrhythmias require different forms of therapy, 
historically, different classes of implantable devices have been used to 
treat them. Thus, "pacemakers" generally deliver low energy pulses for 
treating bradycardia, "cardioverters" deliver stronger pulses for 
reverting tachycardia, and "defibrillators" deliver very strong pulses or 
"shocks" for terminating fibrillation. Modern devices may be capable of 
providing "tiered therapy," in which the type of electrical stimulation 
supplied by the device is determined according to the severity of the 
arrythmia, with more aggressive therapy being applied in response to the 
more severe arrhythmias. For example, a modern device may serve as a 
pacemaker and a cardioverter/defibrillator, which is to say, that it can 
provide therapy for bradycardia, tachycardia and fibrillations. 
As medical science and technology progress, treatments for cardiac 
arrhythmias, and the implantable devices used for their delivery, have 
become more specific and more sophisticated. Typically, a set of 
adjustable parameters in the device is programmed to modify the delivered 
therapy according to the instructions of a physician. These may include 
parameters that adjust detection mode and detection criteria of the 
device--for example, parameters that define bradycardia, tachycardia and 
fibrillation according to rate and regularity, or parameters that 
determine whether the device sensors act in one or two chambers of the 
heart (i.e. single- or dual-chamber sensing). 
Other adjustable parameters determine the pacing mode or the specifications 
of the therapy that the device would deliver in response to any particular 
arrythmia that is detected. For example, a device can be programmed to 
deliver pacing pulses in one or two chambers of the heart (i.e. single- or 
dual-chamber pacing), with or without modulation of the pacing rate 
according to the detected heartbeat. 
Parameters that relate to routine or house-keeping functions of the device 
can also be programmed according to the instructions of a physician. For 
example, the device can be programmed to record the history of a 
particular episode of arrhythmia, such as the date and time of detection, 
heart rate at the time of detection, and result of the therapy. Various 
other sensor and memory storage units within the device can also be 
enabled or disabled to enhance the performance of the device and battery 
longevity, as deemed appropriate by the physician. 
Obviously, the greater the number of adjustable parameters, the greater the 
chance of satisfying particular therapeutic needs of each patient by 
tailoring those parameters. But there is also greater complexity and more 
room for confusion in deciding what the appropriate settings should be. 
Incorrect programming of the device, or presence of two or more 
conflicting parameter settings may lead to device malfunction. It may, for 
example, cause delivery of unnecessary or inappropriate pulses--a 
phenomenon that is categorized as "pacemaker syndrome". 
Thus, an immense burden is placed on the physician or the medical 
technician who must determine the appropriate settings. To make reliable 
decisions, a physician would need familiarity with vast volumes of 
information. Not only must physicians keep abreast of the literature and 
the latest medical advances in the field, they must also understand the 
complexities of various intricate implantable devices. With new and more 
sophisticated devices from different manufacturers entering the market at 
an increasingly rapid pace, this task is becoming more formidable every 
day. 
In spite of some recent attempts in the art to lighten the burden of the 
therapy decision-making process, known systems generally have not advanced 
beyond recommending an optimum pacing mode for implantable pacemakers. For 
example, Bernstein and Parsonnet have described a computer implementation 
of an algorithm that calculates a pacing mode based on 11 pieces of 
encoded data entered by the operating physician (presented at the "39th 
Annual Science Session of the American College of Cardiology," New 
Orleans, La.--March 1990). Similarly, Garber et al. has programmed an 
algorithm on a personal computer that can determine an optimum pacing mode 
following a question-and-answer session with the physician (J. 
Electrophys. (1989) 3, 217-220). 
Simply recommending a pacing mode, however, is unsatisfactory. It can leave 
the physician unaware of why a particular mode was recommended, what 
alternatives are available, or how to set the other adjustable parameters 
on the implantable device. Furthermore, as mentioned previously, in many 
cases two settings may interfere with each other's function and such a 
conflict may easily escape the physician's notice. The recommendations 
made by the prior art systems are also restricted to only one type of 
implantable cardiac stimulating device whereas a physician must typically 
deal with many different devices from various manufacturers. 
Therefore, it would be desirable if a decision support system could present 
the physician with a list of a multitude of available parameters that can 
be adjusted in an implantable device, and if it could make setting 
recommendations on any of those parameters according to the physician's 
choice. Furthermore, it would be desirable if the system could identify 
possible conflicts among parameter settings and warn the physician 
accordingly. It would also be desirable if the decision support system 
presented literature citations or scientific data and reasoning explaining 
why a particular mode or a specific parameter setting was recommended. To 
expand the utility of a decision support system it would also be desirable 
if the decision support system had the flexibility to recognize various 
types and models of implantable cardiac stimulating devices and make 
recommendations accordingly. 
Another shortcoming of the known computer-based systems is that they 
require the physician to perform various tasks on a number of different 
machines or instruments before programming an implantable device. For 
example, to provide a properly programmed device for a new patient, a 
physician first has to obtain a large amount of data regarding the 
patient's medical condition, possibly from a central hospital database, 
and then enter this data into the computer (e.g., a "personal computer") 
on which the system is operating. Next, the physician must provide the 
system with the specifications of the implantable device and the present 
settings of the adjustable parameters in the device. This information is 
typically available through apparatus known as a "device programmer," 
which can communicate with the implantable device telemetrically. Once the 
system is provided with all the necessary information, it can recommend a 
pacing mode. The physician must then go back to the device programmer, and 
adjust the implantable device parameters telemetrically. Having now 
programmed the device, the physician would have to return to the patient 
file or database and make a record of the settings for future reference. 
Clearly, this mode of operation is cumbersome, inefficient and overly 
time-consuming. Therefore, a decision support system that could gather 
some or all of the relevant data automatically would be desirable. It 
would also be desirable if the same decision support system could arrive 
at optimal settings for device parameters after gathering the data, and if 
the same system could automatically program the implantable device 
according to the instructions of the physician. 
SUMMARY OF THE INVENTION 
In accordance with the present invention, a decision support system is 
provided that can generate recommendations for programming of implantable 
cardiac stimulating devices, according to rules from one or more rule sets 
that define the operations of various cardiac stimulating devices. Rule 
sets are selected based on the type of the implantable cardiac stimulating 
device to be programmed. The system utilizes a rule engine unit that 
engages an operator in an interactive question and answer session 
according to the rules of the selected rule set. Based on the information 
acquired from the operator, the rule engine determines an appropriate 
operating condition for the implantable cardiac stimulating device or a 
plurality of operating conditions from which the physician can choose. The 
system then displays the operating condition as a programming 
recommendation to the operator. 
Preferably, the rule sets provide the operator with a list of adjustable 
parameters in an implantable device so that programming recommendations 
regarding any of a number of adjustable parameters in an implantable 
device can be obtained from the same decision support system. 
The present invention also provides a decision support system which 
utilizes a patient/device database unit for storage of medical information 
of patients and operating parameters for various implantable cardiac 
stimulating devices. The patient/device database can also serve as a means 
for storage of the rule sets. The decision support system can thus 
retrieve some or all of the information required for generating a 
recommendation directly from the patient/device database and arrive at a 
programming recommendation. 
Therefore, in accordance with the present invention a method for arriving 
at recommendations for programming of implantable cardiac stimulating 
devices is provided. The method involves selection of an appropriate rule 
set from a set of available rule sets according to information acquired 
from an operator or from a patient/device database. The operator is then 
engaged in a question and answer session wherein questions are posed 
according to the rules of the selected rule set and the operator's answers 
to previous questions. In this way, the operator goes through the rule set 
and upon completion of the session is presented with programming 
recommendations. Preferably, each recommendation is accompanied by 
comments, or citations from the medical literature, or both, describing 
the reasoning which led to the recommendation and references for further 
consultation by the operator. 
The decision support system and method according to the present invention 
can be implemented as part of a cardiac stimulating device programmer. 
Thus, the present invention also provides an implantable device programmer 
capable of delivering programming guidance and decision support. The 
programmer is preferably capable of using the recommended operating 
condition to program an implantable cardiac stimulating device via a 
telemetry head. The programmer can also house a patient/device database 
unit as described above. Thus, an operator can access a patient's medical 
history and operating parameters for various implantable cardiac 
stimulating devices through the programmer's patient/device database, use 
the decision support feature of the programmer to determine an appropriate 
setting or operating condition, store the determined settings in the 
patient/device database, and engage the telemetric capabilities of the 
programmer to program the implantable device, in a single session with a 
device programmer according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION 
The present invention provides a decision support system 20, as shown in 
FIG. 1, that utilizes a central control unit 22 for the orchestration of 
tasks among a number of other units and components including a rule engine 
24, a patient/device database 26, an input interface 28, an output 
interface 30, and a telemetry head 32. In addition, the rule engine 24 has 
access to a number of rule sets 34, stored in a memory unit 36. The 
control unit is typically microprocessor-based and capable of performing 
multiple tasks. For example, as shown in FIG. 1, the control unit 22 
communicates with an implantable cardiac stimulating device 38 through the 
telemetry head 32. The telemetry head 32 allows for bidirectional transfer 
of information. In one direction, the control unit 22 may receive 
information from the implantable cardiac stimulating device regarding the 
implantable device itself (e.g., name, model, current parameter settings, 
etc.) or regarding the operational history of the device and patient 
response to delivered therapy (e.g., date, energy, and cardiac activity of 
the patient following the last attempted therapy). In the other direction, 
the control unit 22 can transmit parameter settings or programming 
instructions to the implantable cardiac stimulating device and thus affect 
the operation of the device, if so desired. The implantable device could 
then stimulate cardiac tissue 40, according to the programmed instructions 
or parameters, through a conventional lead 42. 
In order to determine the optimal parameter settings and programming 
instructions, the control unit 22 utilizes several auxiliary components. 
For example, an interface with the patient/device database 26 provides 
access to further detailed information about patients, and information 
about implantable devices, that may not be directly available from the 
implantable device 38. Such data may comprise the medical history of a 
patient, current drug regimen, and possible susceptibility to certain 
cardiac arrhythmias. The data may also include information such as 
guidelines provided by a manufacturer relating to specific device 
operations, available therapies, and lists of adjustable parameters and 
specifications for various devices. The data stored in the patient/device 
database 26 may relate to many different patients and many different 
implantable cardiac stimulating devices. Thus the decision support system 
20 can be used in programming of a variety of different devices for many 
different patients. 
As shown in FIG. 1, the patient/device database 26 may be implemented as 
part of the decision support system 20 using conventional data storage 
apparatus, such as a read-only memory cartridge, an optical disk drive, a 
hard disk drive, a floppy disk drive, a tape drive, or any other suitable 
data storage device. Alternatively, the database may be separate from the 
decision support system, as part of an accessory unit such as a mainframe 
computer in a hospital or any other central database (not shown). 
The control unit 22 may also acquire information from the operator of the 
device such as a physician or a nurse, through the input interface 28. The 
input interface 28 can be a keyboard, a touch sensitive screen, a screen 
with a light pen, or any suitable interface that would allow the user to 
communicate with the control unit 22. 
Messages and data can be displayed through the output interface 28, which 
may be a display monitor, a printer, or any other suitable apparatus for 
output of information. 
The control unit 22 uses a rule engine 24, preferably at least partly 
microprocessor-based, to provide the operator with suggestions regarding 
the programming of the implantable device. Although FIG. 1 depicts the 
control unit 22 and the rule engine 24 as separate units of the decision 
support system, they can also be implemented with the same microprocessor. 
Preferably, the rule engine 24 is flexible in that it can operate 
according to a variety of different rule sets 34, corresponding to 
different implantable cardiac stimulating devices. 
The rule sets 34 are stored in a memory unit 36, which may comprise a 
read-only memory cartridge, an optical disk drive, a hard disk drive, a 
floppy disk drive, a tape drive, or any other suitable data storage 
device. The rule engine 24 is linked to the memory unit 36 so that it can 
retrieve and load an appropriate rule set according to the instructions of 
control unit 22. The memory unit 36 may be implemented as part of the 
patient/device database 26. 
FIGS. 2, 3 and 4 illustrate the decision support system of the present 
invention under control of a computer program. The program may be 
implemented in suitable microcode or any higher level computer language. 
In operation, the computer program causes the system to perform at least 
five basic tasks as shown schematically in FIG. 2. Initially, the system 
goes through a data gathering step 50, in which it acquires information 
regarding the patient (not shown) and the implantable cardiac stimulating 
device 40 (FIG. 1), that would be required for making a recommendation. 
Next, at a step 52, the system activates the rule engine 24 (FIG. 1) and, 
through the rule engine 24, selects an appropriate rule set 34 
corresponding to the implantable cardiac stimulating device 40 that is to 
be programmed (FIG. 1). With the rule engine activated, the system 
proceeds to a step 54 at which point it guides the operator through an 
interactive question and answer session. At the step 54, the rule engine 
determines the questions posed to the operator according to the rule set 
34 (FIG. 1) and based on the answers of the operator to previous 
questions. The session is continued until the rule engine 24 (FIG. 1) can 
provide a recommendation or set of recommendations from which the 
physician may choose. At that time, the system advances to a step 56 and 
displays the recommendation through the output interface 30 (FIG. 1). Any 
recommendation is preferably accompanied by a list of medical literature 
references upon which the recommendation is based. 
Next, a test 58 is performed to determine whether the operator accepts the 
recommended setting for programming the device. A "yes" answer leads to a 
step 60 in which the telemetry head 32 (FIG. 1) is automatically activated 
and programming instructions are transmitted to the implantable cardiac 
stimulating device. A "no" answer at test 58, indicating that the operator 
is not satisfied with the recommendation, returns the system to the step 
50 so that the operator can seek another recommendation. A loop 
encompassing the steps 50-56 and the test 58 can be repeated as many times 
as required until a satisfactory recommendation is obtained. 
FIGS. 3 and 4 provide a more detailed description of the decision support 
system of this invention under control of a computer program. Here, the 
operator (not shown) would begin by choosing the mode in which the system 
is to acquire the desired information. First, at a test 62, the operator 
is provided with the choice of using the telemetric capabilities of the 
system to obtain information telemetrically from the implantable cardiac 
stimulating device 22 (FIG. 1). If so desired (answer "yes" to the test 
62), then the system would activate the telemetry head 32 (FIG. 1) at a 
step 64 and access the memory (not shown) of the implantable cardiac 
stimulating device 38 (FIG. 1) at a step 66. Depending on the model and 
specifications of the implantable cardiac stimulating device 38 (FIG. 1), 
various pieces of information may be stored in its memory. Following step 
66, the system would proceed to a step 72 to display the gathered 
information or, depending on the implementation, proceed to a step 70 to 
retrieve additional information from the database. This information may 
include technical information such as a list of parameter settings, or 
personal data on the patient, such as medical history, and recent cardiac 
activity as recorded by the device. 
Alternatively, the operator may obtain information by accessing the 
patient/device database 26 (FIG. 1). To do this the system advances to a 
step 68 in response to a "no" answer to the test 62, and asks for the 
patient name or an identification number. This can be entered through the 
input interface 28 (FIG. 1). Having the name or the identification number 
of the patient, the system can search through the database 26 (FIG. 1) and 
retrieve whatever pertinent information is available in the database at 
step 70. 
Regardless of the mode of information retrieval (telemetric or 
database-assisted), all of the gathered information is then displayed for 
the operator's perusal at step 72. (Alternatively, the operator could be 
asked to review and accept the data one piece at a time.) A test 74 is 
performed to determine if the operator finds the retrieved information 
sufficient and satisfactory. If the answer is "no" (for example, when the 
medical condition or drug regimen of the patient has changed since the 
last update of the patient/device database 26 (FIG. 1), or if the operator 
finds an error in the displayed record), then the system would move to a 
step 76 and begin to collect the correct and up-to-date information. Input 
of data by the operator can be facilitated using any known user-friendly 
data entry protocols. For example, the invention may be practiced using a 
mouse and menu bars, touch-sensitive screens, or pen-based computers. 
Once the correct patient and device information have been gathered, the 
system activates the rule engine 24 (FIG. 1) at a step 78. The rule engine 
can then use this information at step 80 to select an appropriate rule set 
from one of the rule sets 34 (FIG. 1). As noted before, each rule set is 
marked in the system's memory 36 (FIG. 1) according to the implantable 
devices to which its rules apply. The appropriate rule set 34 (FIG. 1) may 
comprise a predefined decision tree, or alternatively, a multitude of 
interacting rules that are cross-referenced to each other in such a way 
that they can generate numerous different trees, depending on the order in 
which different rules are activated. The latter are commonly known as 
"deduction-oriented" rules or "antecedent-consequent" rule sets. 
Regardless of the type of rule-set employed, the system then displays a 
list of parameters that can be adjusted in the implantable device at a 
step 82 (FIG. 4). The list is available either from the selected rule 
set--since each rule set is defined for a particular implantable 
device--or in an alternative embodiment from the patient/device database 
26 (FIG. 1). 
The operator is then asked to select, at a step 84, the parameter 
adjustment for which decision support is requested. (Alternatively, the 
system may select a default parameter adjustment, thereby not requiring a 
selection by the operator.) Following the operator's response, the system 
advances to an interactive question and answer step 86, led by the rule 
engine 24 (FIG. 1). The operator may select simply "yes" or "no" answers 
to certain questions or select from multiple-choice answers to others. 
Each question and possible answers to that question are displayed through 
the output interface 30 (FIG. 1). Each answer leads the rule engine 24 
(FIG. 1) either to a new question, or to a recommendation. When a 
recommendation has been reached, it is displayed, together with the 
appropriate literature references, at a step 88. At a test 89, the 
operator is asked if he would like to review the answers that he had given 
at step 86 that caused the system to give the recommendation displayed. If 
the operator answers no, the system proceeds to a test 90. If the operator 
answers yes at test 89, the system proceeds to a test 87 and displays the 
answers given previously and asks if the operator would like to modify 
those answers. If the operator answers yes, the system returns to 
interactive question and answer step 86. (An additional step could be 
performed, wherein the operator is asked which answer he would like to 
modify and the interactive question and answer step 86 is restarted from 
the corresponding question.) If at test 87, the operator answers no, the 
system returns to test 89. If at test 89, the operator answered yes, test 
90 is performed to determine whether the operator would like another 
recommendation--either for the adjustment of another parameter, or based 
on different answers during the question and answer step 86. If the answer 
is "yes", then the system asks whether the current recommendation should 
be saved at a test 92. The system is capable of storing several 
recommendations or programming instructions, so that the operator can 
collect all the necessary recommendations before programming the 
implantable cardiac stimulating device 38 (FIG. 1). In this way, the 
system can avoid piecemeal programming of the implantable cardiac 
stimulating device 38 (FIG. 1) and it would allow the operator to adjust 
several parameters all at once. A "yes" answer to the test 92 advances the 
system to a step 94, at which point the current recommendation is saved, 
before returning to the step 82 to determine which parameter is to be 
adjusted next. A "no" answer to the test 92 returns the system to the step 
82 directly. 
A loop consisting of the steps 82-94 can be repeated until no other 
recommendations are required. At that point, a "no" response at the test 
90 causes the system to proceed to a test 96 which determines whether the 
operator would like to program the implantable cardiac stimulating device 
38 (FIG. 1) telemetrically. If so desired ("yes" answer), the system would 
automatically display the parameters that it plans to program and the 
recommended settings at a step 98. At this stage, the operator can use 
discretion to alter the recommendations of the decision support system 
before adjusting the implantable cardiac stimulating device 38 (FIG. 1) 
telemetrically. A test 100 is performed to allow for such alterations. If 
at test 100 the operator answers "yes", then the preferred settings can be 
entered at step 102 through the input interface 28 (FIG. 1). When the 
desired programming parameters have been set, the operator can initiate 
telemetric programming by entering a "no" answer at the test 100. This 
causes the system to activate telemetry head 32 (FIG. 1) at a step 104 and 
adjust the appropriate parameters at a step 106 according to the 
recommendation(s) made at the step 88. 
The system then returns to the test 90 should the operator choose to adjust 
other parameters in the device, in which case the steps 92-88 are 
repeated. If not, the answers at tests 90 and 96 would be "no" which 
brings the program to an end. 
To illustrate further a decision-making process of this invention, FIGS. 5 
and 6 show a decision tree that can be used as one of the rule sets 34 
(FIG. 1) in the programs represented in FIGS. 2, 3 and 4. This decision 
tree is an example of a rule set used for making recommendations in 
adjusting the pacing mode of an implantable pacemaker. However, it would 
be clear to those skilled in the art that similar decision trees can be 
easily constructed for adjustment of parameters other than for the pacing 
mode, and for programming of other implantable cardiac stimulating devices 
such as an implantable cardioverter or an implantable 
cardioverter/defibrillator. 
As seen in FIGS. 5 and 6, the decision tree provides a "multi-linear" rule 
set in which questions are organized in a hierarchical fashion. At each 
branching point or "node," the operator is presented either with a choice 
of yes/no answers (e.g., at a node 4, FIG. 5) or with multiple choices 
(e.g., at a node 5, FIG. 5). Each answer determines the next question, and 
ultimately leads to a recommendation at the outermost tips of the branches 
of the tree. In the tree of FIGS. 5 and 6, there are 62 such tips 
corresponding to 62 different recommendations for the adjustable 
pacing-mode parameter. The descent to each recommendation and the basis 
for the recommended pacing mode is described in detail in an attached 
Appendix. 
To illustrate further the decision making process, FIG. 7 follows the 
progress of a hypothetical question-and-answer session along one of the 
branches of the decision tree in FIGS. 5 and 6. This branch corresponds to 
Mode Selection Conclusion 42 (see appendix). As shown in FIG. 7, the 
system begins by ascertaining whether the patient needs a pacemaker (node 
120), whether the use of the pacemaker would be frequent (node 122), and 
if the patient is mentally competent (node 124). In this hypothetical 
case, the patient is a mentally competent subject with frequent need for a 
pacemaker due to an atrioventricular (AV) block. Therefore, the answers to 
the questions posed at the nodes 120, 122, and 124 are "yes", "no", and 
"no", respectively. Although in this example the answers are provided by 
the operator, they can also be retrieved from the patient/device database 
26 (FIG. 1) prior to the question-and-answer session. In that case, the 
system retrieves answers to as many questions as possible from the 
database, and then begins to ask for answers to the unanswered questions. 
Following the answer to the question of the node 124, the system proceeds 
to inquire at a node 126 about the possibility of atrial fibrillation at a 
node 126. The node 126 is an example of a node which can lead to multiple 
(more than 2) sub-branches. In this case, the answer "none", indicating no 
evidence of atrial fibrillation, leads to a node 128 which, like the node 
126, can lead to multiple sub-branches. When the sinus rhythm is normal, 
as is the case in the hypothetical example of FIG. 7, the system proceeds 
to nodes 130-134 to determine if there is possibility of AV block, a 
hypertrophied non-compliant ventricle, or evidence of pacemaker syndrome. 
Appropriate answers to these questions lead to a node 136 which determines 
if a separate sensor (not shown) for rate-responsive pacing should be 
activated, in case the sinus rate may exceed the maximum tracking rate. 
Since this is not a concern in this hypothetical case, the answer to the 
question of the node 136 is "no". At this point the system requires no 
further information for recommending a pacing-mode, and proceeds to 
recommend DDD at node 138 (dual-chamber pacing and dual-chamber sensing 
with rate modulation due to atrial tracking) pacing mode for the 
hypothetical patient. Significantly, the recommendation for DDD pacing 
mode is accompanied by the following comments: with documented pacemaker 
syndrome, whether it being during ventricular pacing or its functional 
equivalent (a junctive rhythm with loss of AV synchrony, or PVC with 
retrograde conduction), it is essential to maintain an appropriate 
atrio-ventricular contraction sequence. For further explanation, the 
following scientific articles explain the reasoning behind this 
recommendation: Barold, S., "Cardiac Pacing Hemodynamics: The Pacemaker 
Syndrome", Cardio, (September) 1991; 8:36-51; Heldman, D., et al, "True 
Incidence of Pacemaking Syndrome", E, 1990, 13:1742-1750; and Aussbel, 
U. and Furman, S., "The Pacemaker Syndrome", Annual of Internal Medicine, 
1985; 103:420-429. 
As mentioned previously, the decision tree of FIGS. 5 and 6 provides a 
multi-linear rule set, which is to say that each of its conclusions 
(branch tips) is the result of specific answers to a set of questions 
arranged in a predetermined order. To generate such a tree, a set of 
questions are ordered, ideally from most general to most specific, and the 
system would lead the operator through the questions in that order. 
However, when multiple factors affect the operations of a device 
interdependently, as in the case for most implantable cardiac stimulating 
devices, the ranking of different questions becomes an exceedingly 
difficult and often subjective process. To overcome such problems, the 
rule sets may arrange a set of questions in an interdependent manner, such 
that each question appears not in a hierarchical order but depending on 
the history of the answers given previously. 
Thus in some embodiments of the rule sets in accordance with this 
invention, the order in which questions are posed is neither predetermined 
nor linear. Such rule sets are well known (see, for example, P. H. Winston 
Artificial Intelligence 2nd Ed., Addison Wesley, pp. 166-204 (1984)) and 
can be implemented using programming subroutines in artificial 
intelligence (AI) shells based on any of the well known computer 
programming languages. 
Thus, it is seen that a decision support system is provided that can aid 
physicians in selection and adjustment of appropriate parameters in 
implantable cardiac stimulating devices. This decision support system not 
only aids the physician in optimizing the operations of an implantable 
cardiac stimulating device, but also provides a bibliographic reference 
system to facilitate the decision making process. One skilled in the art 
will appreciate that the present invention can be practiced by other than 
the described embodiments, which are presented for purposes of 
illustration and not of limitation, and the present invention is limited 
only by the claims which follow. 
APPENDIX 
Mode Selection Conclusion 1 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
Yes. 
3. Is the indication for pacing a neuroregulatory abnormality such as 
malignant vasovagal syncope or hypersensitive carotid sinus syndrome? 
Yes. 
Recommended Mode: DDI 
Comment: These patients usually have a vasodepressor component in addition 
to bradycardia. They need maintenance of atrial transport in addition to 
rate support but they do not require atrial pacing 1!. 
Reference 1!: Fitzpatrick, A. et al., "Dual-Chamber Pacing Aborts 
Vasovagal Syncope Induced by Headup 60.degree. Tilt," Pace 1991; 14; 
13-19. 
Mode Selection Conclusion 2 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
Yes. 
3. Is the indication for pacing a neuroregulatory abnormality such as 
malignant vasovagal syncope or hypersensitive carotid sinus syndrome? 
No. 
Recommended Mode: VVI with hysteresis 
Comment: VVI with hysteresis will prevent asystole but otherwise prevent 
the pacemaker from interfering with the patient's intrinsic rhythm. The 
limitation of this mode is that it does not allow for progression of 
conduction system disease when pacing may be required frequently at which 
point restoration of AV synchrony or rate modulation may be of value for 
the patient. 
Mode Selection Conclusion 3 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
Yes. 
Recommended Mode: VVI 
Comment: Despite the very limited functional status of the patient, one 
should carefully evaluate the effect of ventricular pacing on blood 
pressure and cardiac output. These patients may have pacemaker syndrome at 
which time, VVI pacing can worsen this clinical status, and despite their 
limited functional existence, dual pacing may be necessary if pacing and 
therapy is recommended. 
Mode Selection Conclusion 4 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
Chronic. 
6. Does the Ventricular rate increase with physiologic stress? 
Yes. 
Recommended Mode: VVI Alternate: VVIR 
Comment: While base rate pacing is all that is required at the time of 
implantation, progression of AV nodal conduction disease due to intrinsic 
pathologic processes or medications may render the patient 
chronotropically incompetent in the future. Rate modulated capability will 
allow for management of all options. 
Mode Selection Conclusion 5 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
Chronic. 
6. Does the Ventricular rate increase with physiologic stress? 
No. 
Recommended Mode: VVIR 
Comment: In patients whose ventricular rate does not increase with stress, 
exercise tolerance will be improved with the addition of rate modulation 
2!. 
Given the chronic atrial fibrillation, the only option is single chamber 
ventricular pacing. 
Reference 2!: Humen, D. P. et al., "Activity-Sensing Rate-Responsive 
Pacing: Improvement in Myocardial Performance with Exercise," Pace, 1985; 
8: 52-59. 
Lau, C. P. et al., "Symptomology and Quality of Life in Patients with 
Rate-responsive Pacemaker: a Double-Blind Study," Clinical Cardiology, 
1989; 12: 505-512. 
Lau, C. P. et al., "Ventricular Rate-Adaptive Pacing in the Elderly," 
European Heart Journal, 1992; 13: 908-913. 
Mode Selection Conclusion 6 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
Intermittent. 
7. When is the pacemaker required? 
1. During Atrial Fib. 
2. Immediately after conversion (i.e. prolonged Sinus Node recovery time) 
3. During Sinus rhythm due to marked bradycardia 
1 only. 
Recommended Mode: DDI(R) Alternate: VVI 
Second alternative: VVIR 
Comment: DDI(R): As the atrial fibrillation is intermittent, one might want 
to consider the DDI mode. This will not track the fibrillatory wave, but 
will provide back-up ventricular pacing support when AV Block is present 
during Atrial Fibrillation. During sinus rhythm, it will provide atrial 
pacing which may stabilize the atrial rhythm and prevent or minimize the 
episodes of fibrillation 3!. 
While base rate pacing is all that is required at the time of implantation, 
progression of AV nodal conduction disease due to intrinsic pathologic 
processes or medications may render the patient chronotropically 
incompetent in the future. Rate modulated capability will allow for 
management of all options. 
For VVI: The patient only needs pacing during atrial fibrillation, hence 
for AV block at this time, the only mode which will be effective is VVI. 
For VVIR: If the level of AV block is persistent during atrial 
fibrillation, consider a VVIR unit to improve exercise tolerance at these 
times. However, a VVIR may also increase its rate when the patient is in 
sinus rhythm, usurping control of the ventricle and induce pacemaker 
syndrome. The best mode to treat all options is DDIR. 
Reference 3!: Bana, G. et al., "DDI Pacing in the Bradycardia-Tachycardia 
Syndrome," Pace, 1990; 13: 264-270. 
Markewitz, A. et al., "What is the Most Appropriate Stimulation Mode in 
Patients with Sinus Node Dysfunction?" Pace, 1986; 9: 1115-1120. 
Mode Selection Conclusion 7 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
Intermittent 
7. When is the pacemaker required? 
1. During Atrial Fib. 
2. Immediately after conversion (i.e. prolonged Sinus Node recovery time) 
3. During Sinus rhythm due to marked bradycardia 
2 only. 
8. Is there a hypertrophied, non-compliant ventricle? 
Yes. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
No. 
Recommended Mode: DDI Alternate: DDIR 
Comment: Although AV block is not present initially, pharmacologic therapy 
needed to control the ventricular response to the atrial fibrillation may 
unmask AV block, making single chamber AAI pacing unsafe. This same 
pharmacologic therapy may blunt chronotropic responsiveness warranting 
rate modulation. 
Given the hypertrophied, non-compliant ventricle, one wants to maintain AV 
synchrony as much as possible when the atrium is NOT fibrillation. Hence 
VVI and VVIR are not appropriate in this setting. 
While base rate pacing is all that is required at the time of implantation, 
progression of sinus or AV nodal conduction disease due to intrinsic 
pathologic processes or medications may render the patient 
chronotropically incompetent in the future. Rate modulated capability will 
allow for management of all options. 
Mode Selection Conclusion 8 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
Intermittent. 
7. When is the pacemaker required? 
1. During Atrial Fib. 
2. Immediately after conversion (i.e. prolonged Sinus Node recovery time) 
3. During Sinus rhythm due to marked bradycardia 
2 only. 
8. Is there a hypertrophied, non-compliant ventricle? 
Yes. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
Yes. 
Recommended Mode: DDI Alternate: DDDR 
Comment: Pharmacologic therapy needed to control the ventricular response 
to the atrial fibrillation may exacerbate AV block, making single chamber 
AAI pacing unsafe. This same pharmacologic therapy may blunt chronotropic 
responsiveness warranting rate modulation. 
As the atrial fibrillation is intermittent, one might want to consider the 
DDI mode. This will not track the fibrillatory wave, but will provide 
back-up ventricular pacing support when AV Block is present during atrial 
fibrillation. During sinus rhythm, it will provide atrial pacing which may 
stabilize the atrial rhythm and prevent or minimize episodes of 
fibrillation 3!. 
As the DDD mode tracks endogenous atrial activity, DDDR is the optimum mode 
but only when the MTR and MSR can be independently programmed. A low MTR 
is chosen to minimize the rate increase when the atrial fibrillation. 
During activity, a high MSR allows an appropriate increase in rate. In the 
absence of this capability, choose DDIR. 
The only time the patient requires pacing is for protection against 
asystole episodes associated with the prolonged sinus node recovery time 
following conversion to MSR from atrial fibrillation. Given the concern 
about AV Block, dual chamber base rate pacing is recommended. However, 
this does not protect the patient against progression of disease or 
further compromise from required medications. 
Given the hypertrophied, non-complaint ventricle, one wants to maintain AV 
synchrony as much as possible when the atrium is NOT fibrillation? Hence 
VVI and VVIR are not appropriate in this setting. 
While base rate pacing is all that is required at the time of implantation, 
progression of sinus or AV nodal conduction disease due to intrinsic 
pathologic processes or medications may render the patient 
chronotropically incompetent in the future. Rate modulated capability will 
allow for management of all options. 
Reference 3!: Bana, G. et al., "DDI Pacing in the Bradycardia-Tachycardia 
Syndrome," Pace, 1990; 13: 264-270. 
Markewitz, A. et al., "What is the Most Appropriate Stimulation Mode in 
Patients with Sinus Mode in Patients with Sinus Node Dysfunction?" Pace, 
1986; 9: 1115-1120. 
Mode Selection Conclusion 9 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
Intermittent. 
7. When is the pacemaker required? 
1. During Atrial Fib. 
2. Immediately after conversion (i.e. prolonged Sinus Node recovery time) 
3. During Sinus rhythm due to marked bradycardia 
2 only. 
8. Is there a hypertrophied, non-compliant ventricle? 
No. 
9. Is there evidence of pacemaker syndrome (fall in blood pressure, 
retrograde conduction, fall in cardiac output) with ventricular pacing or 
pre-pacing native rhythm when AV synchrony is lost? 
Yes. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
Yes. 
10. Does Atrial rate increase with physiologic stress? 
Yes. 
Recommended Mode: DDI(R) Alternate: DDD(R) 
Comment: The only time the patient requires pacing is for protection 
against asystole episodes associated with the prolonged sinus node 
recovery time following conversion to MSR from atrial fibrillation. Given 
the concern about AV Block, dual chamber base rate pacing is recommended. 
However, this does not protect the patient against progression of disease 
or further compromise from required medications 2!. 
Pharmacologic therapy needed to control the ventricular response to the 
atrial fibrillation may exacerbate AV block making single chamber AAI 
pacing unsafe. This same pharmacologic therapy may blunt chronotropic 
responsiveness warranting rate modulation. 
The persistent sinus bradycardia requires both atrial pacing and rate 
modulation. As pharmacologic therapy to control the ventricular response 
to atrial fibrillation, dual chamber pacing in the form of DDIR will 
provide back-up ventricular support should AV block develop. 
With documented pacemaker syndrome--whether it be during ventricular pacing 
or its functional equivalent (a junctive rhythm with loss of AV synchrony, 
PVCs: with retrograde conduction) it is essential to maintain an 
appropriate atrio-ventricular contraction sequence 3!. 
While base rate pacing is all that is required at the time of implantation, 
progression of sinus or AV nodal conduction disease due to intrinsic 
pathologic processes or medications may render the patient 
chronotropically incompetent in the future. Rate modulated capability will 
allow for management of all options. 
As the DDD mode tracks endogenous atrial activity, DDDR is the optimum mode 
but only when the MTR and MSR can be independently programmed. A low MTR 
is chosen to minimize the rate increase when inatrial fibrillation. During 
activity, a high MSR allows an appropriate increase in rate. In the 
absence of this capability, choose DDIR. 
Reference 3!: Bana, G. et al., "DDI Pacing in the Bradycardia-Tachycardia 
Syndrome," Pace, 1990; 13: 264-270. 
Markewitz, A. et al., "What is the Most Appropriate Stimulation Mode in 
Patients with Sinus Node Dysfunction?" Pace, 1986; 9: 1115-1120. 
Reference 4!: Barold, S. S., "Cardiac Pacing Hemodynamics: The Pacemaker 
Syndrome," Cardio, 1991; 8: (September) 36-51. 
Heldman, D. et al., "True Incidence of Pacemaker Syndrome," Pace, 1990; 13: 
1742-1750. 
Aussbel, U., Furman, S., "The Pacemaker Syndrome, Ann (?) Internal 
Medicine," 1985; 103: 420-429. 
Mode Selection Conclusion 10 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
Intermittent. 
7. When is the pacemaker required? 
1. During Atrial Fib. 
2. Immediately after conversion (i.e. prolonged Sinus Node recovery time) 
3. During Sinus rhythm due to marked bradycardia 
2 only. 
8. Is there a hypertrophied, non-compliant ventricle? 
No. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
Yes. 
10. Does Atrial rate increase with physiologic stress? 
No. 
Recommended Mode: DDIR Alternate: DDDR 
Comment: The persistent sinus bradycardia requires both atrial pacing and 
rate modulation. As pharmacologic therapy to control the ventricular 
response to atrial fibrillation, dual chamber pacing in the form of DDIR 
will provide back-up ventricular support should AV block develop. 
As the DDD mode tracks endogenous atrial activity, DDDR is the optimum mode 
but only when the MTR and MSR can be independently programmed. A low MTR 
is chosen to minimize the rate increase when inatrial fibrillation. During 
activity, a high MSR allows an appropriate increase in rate. In the 
absence of this capability, choose DDIR. 
While base rate pacing is all that is required at the time of implantation, 
progression of AV nodal conduction disease due to intrinsic pathologic 
processes or medications may render the patient chronotropically 
incompetent in the future. Rate modulated capability will allow for 
management of all options. 
Mode Selection Conclusion 11 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
Intermittent. 
7. When is the pacemaker required? 
1. During Atrial Fib. 
2. Immediately after conversion (i.e. prolonged Sinus Node recovery time) 
3. During Sinus rhythm due to marked bradycardia 
2 only. 
8. Is there a hypertrophied, non-compliant ventricle? 
No. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
No. 
10. Does Atrial rate increase with physiologic stress? 
Yes. 
Recommended mode: AAI Alternate: DDI 
Comment: The persistent sinus bradycardia requires both atrial pacing and 
rate modulation. As pharmacologic therapy to control the ventricular 
response to atrial fibrillation, dual chamber pacing in the form of DDIR 
will provide back-up ventricular support should AV block develop. 
Mode Selection Conclusion 12 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
Intermittent. 
7. When is the pacemaker required? 
1. During Atrial Fib. 
2. Immediately after conversion (i.e. prolonged Sinus Node recovery time) 
3. During Sinus rhythm due to marked bradycardia 
2 only. 
8. Is there a hypertrophied, non-compliant ventricle? 
No. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
No. 
10. Does Atrial rate increase with physiologic stress? 
No. 
Recommended mode: AAIR Alternate: DDIR 
Comment: The persistent sinus bradycardia requires both atrial pacing and 
rate modulation. As pharmacologic therapy to control the ventricular 
response to atrial fibrillation, dual chamber pacing in the form of DDIR 
will provide back-up ventricular support should AV block develop. 
While base rate pacing is all that is required at the time of implantation, 
progression of AV nodal conduction disease due to intrinsic pathologic 
processes or medications may render the patient chronotropically 
incompetent in the future. Rate modulated capability will allow for 
management of all options. 
Mode Selection Conclusion 13 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
Intermittent. 
7. When is the pacemaker required? 
1. During Atrial Fib. 
2. Immediately after conversion (i.e. prolonged Sinus Node recovery time) 
3. During Sinus rhythm due to marked bradycardia 
1 and 2. 
8. Is there a hypertrophied, non-compliant ventricle? 
Yes. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
Yes. 
10. Does Atrial rate increase with physiologic stress? 
Yes. 
Recommended mode: DDDR Alternate: DDD 
Comment: Despite the atrial fibrillation, the presence of AV block mandates 
DDD pacing. To minimize tracking the high rate during the atrial 
fibrillation but still allowing for an appropriate rate increase with 
exercise, choose DDDR in a system with independently programmable MTR and 
MSR. 
As the DDD mode tracks endogenous atrial activity, DDDR is the optimum mode 
but only when the MTR and MSR can be independently programmed. A low MTR 
is chosen to minimize the rate increase when inatrial fibrillation. During 
activity, a high MSR allows an appropriate increase in rate. In the 
absence of this capability, choose DDIR. 
Given the hypertrophied, non-compliant ventricle, one wants to maintain AV 
synchrony as much as possible when the atrium is NOT fibrillation. Hence 
VVI and VVIR are not appropriate in this setting. 
Mode Selection Conclusion 14 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
Intermittent. 
7. When is the pacemaker required? 
1. During Atrial Fib. 
2. Immediately after conversion (i.e. prolonged Sinus Node recovery time) 
3. During Sinus rhythm due to marked bradycardia 
1 and 2. 
8. Is there a hypertrophied, non-compliant ventricle? 
Yes. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
Yes. 
10. Does Atrial rate increase with physiologic stress? 
No. 
Recommended mode: DDDR 
Comment: Despite the atrial fibrillation, the presence of AV block mandates 
DDD pacing. To minimize tracking the high rate during the atrial 
fibrillation but still allowing for an appropriate rate increase with 
exercise, choose DDDR in a system with independently programmable MTR and 
MSR. 
As the DDD mode tracks endogenous atrial activity, DDDR is the optimum mode 
but only when the MTR and MSR can be independently programmed. A low MTR 
is chosen to minimize the rate increase when the atrial fibrillation. 
During activity, a high MSR allows an appropriate increase in rate. In the 
absence of this capability, choose DDIR. 
Given the hypertrophied, non-compliant ventricle, one wants to maintain AV 
synchrony as much as possible when the atrium is NOT fibrillation. Hence 
VVI and VVIR are not appropriate in this setting. 
Mode Selection Conclusion 15 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
Intermittent. 
7. When is the pacemaker required? 
1. During Atrial Fib. 
2. Immediately after conversion (i.e. prolonged Sinus Node recovery time) 
3. During Sinus rhythm due to marked bradycardia 
1 and 2. 
8. Is there a hypertrophied, non-compliant ventricle? 
Yes. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
No. 
10. Does Atrial rate increase with physiologic stress? 
Yes. 
Recommended mode: DDI Alternate: DDIR 
Comment: The fact that pacing support is required during periods of atrial 
fibrillation indicating that there is some degree of VA block, even if 
only at very rapid atrial rates at which time back-up ventricular pacing 
is required. Thus AAI would not be appropriate in this setting. 
As the atrial fibrillation is intermittent, one might want to consider the 
DDI mode. This will not track the fibrillatory wave, but will provide 
back-up ventricular pacing support when AV Block is present during atrial 
fibrillation. During sinus rhythm, it will provide atrial pacing which may 
stabilize the atrial rhythm and prevent or minimize the episodes of 
fibrillation 3!. 
Given the hypertrophied, non-compliant ventricle, one wants to maintain AV 
synchrony as much as possible when the atrium is NOT fibrillation. Hence 
VVI and VVIR are not appropriate in this setting. 
While base rate pacing is all that is required at the time of implantation, 
progression of AV nodal conduction disease due to intrinsic pathologic 
processes or medications may render the patient chronotropically 
incompetent in the future. Rate modulated capability will allow for 
management of all options. 
Mode Selection Conclusion 16 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
Intermittent. 
7. When is the pacemaker required? 
1. During Atrial Fib. 
2. Immediately after conversion (i.e. prolonged Sinus Node recovery time) 
3. During Sinus rhythm due to marked bradycardia 
1 and 2. 
8. Is there a hypertrophied, non-compliant ventricle? 
Yes. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
No. 
10. Does Atrial rate increase with physiologic stress? 
No. 
Recommended Mode: DDIR 
Comment: The fact that pacing support is required during periods of atrial 
fibrillation indicating that there is some degree of VA block, even if 
only at very rapid atrial rates at which time back-up ventricular pacing 
is required. Thus AAI would not be appropriate in this setting. 
As the atrial fibrillation is intermittent, one might want to consider the 
DDI mode. This will not track the fibrillatory wave, but will provide 
back-up ventricular pacing support when AV Block is present during atrial 
fibrillation. During sinus rhythm, it will provide atrial pacing which may 
stabilize the atrial rhythm and prevent or minimize episodes of 
fibrillation. 
Given the hypertrophied, non-compliant ventricle, one wants to maintain AV 
synchrony as much as possible when the atrium is NOT fibrillation. Hence 
VVI and VVIR are not appropriate in this setting. 
Mode Selection Conclusion 17 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
Intermittent. 
7. When is the pacemaker required? 
1. During Atrial fib. 
2. Immediately after conversion (i.e. prolonged Sinus Node recovery time) 
3. During Sinus rhythm due to marked bradycardia 
1 and 2. 
8. Is there a hypertrophied, non-compliant ventricle? 
No. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
Yes. 
10. Does Atrial rate increase with physiologic stress? 
Yes. 
Recommended Mode: DDD Alternate: DDDR 
Comment: Despite the atrial fibrillation, presence of AV block mandates DDD 
pacing. To minimize tracking the high rate during the atrial fibrillation 
but still allowing for an appropriate rate increase with exercise, choose 
DDDR in a system with independently programmable MTR and MSR. 
The only time the patient requires pacing is for protection against 
asystole episodes associated with the prolonged sinus node recovery time 
following conversion to MSR from atrial fibrillation. Given the concern 
about AV Block, dual chamber base rate pacing is recommended. However, 
this does not protect the patient against progression of disease or 
further compromise from required medications 3!. 
As the DDD mode tracks endogenous atrial activity, DDDR is the optimum mode 
but only when the MTR and MSR can be independently programmed. A low MTR 
is chosen to minimize the rate increase when inatrial fibrillation. During 
activity, a high MSR allows an appropriate increase in rate. In the 
absence of this capability, choose DDIR. 
While base rate pacing is all that is required at the time of implantation, 
progression of AV nodal conduction disease due to intrinsic pathologic 
processes or medications may render the patient chronotropically 
incompetent in the future. Rate modulated capability will allow for 
management of all options. 
Reference 3!: Bana, G. et al., "DDI Pacing in the Bradycardia-Tachycardia 
Syndrome," Pace, 1990; 13: 264-270. 
Markewitz, A. et al., "What is the Most Appropriate Stimulation Mode in 
Patients with Sinus Node Dysfunction?" Pace, 1986; 9: 1115-1120. 
Mode Selection Conclusion 18 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
Intermittent. 
7. When is the pacemaker required? 
1. During Atrial fib. 
2. Immediately after conversion (i.e. prolonged Sinus Node recovery time) 
3. During Sinus rhythm due to marked bradycardia 
1 and 2. 
8. Is there a hypertrophied, non-compliant ventricle? 
No. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
Yes. 
10. Does Atrial rate increase with physiologic stress? 
No. 
Recommended mode: DDDR 
Comment: Despite the atrial fibrillation, presence of AV block mandates DDD 
pacing. To minimize tracking the high rate during the atrial fibrillation 
but still allowing for an appropriate rate increase with exercise, choose 
DDDR in a system with independently programmable MTR and MSR. 
As the DDD mode tracks endogenous atrial activity, DDDR is the optimum mode 
but only when the MTR and MSR can be independently programmed. A low MTR 
is chosen to minimize the rate increase when in atrial fibrillation. 
During activity, a high MSR allows an appropriate increase in rate. In the 
absence of this capability, choose DDIR. 
Mode Selection Conclusion 19 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
Intermittent. 
7. When is the pacemaker required? 
1. During Atrial fib. 
2. Immediately after conversion (i.e. prolonged Sinus Node recovery time) 
3. During Sinus rhythm due to marked bradycardia 
1 and 2. 
8. Is there a hypertrophied, non-compliant ventricle? 
No. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
No. 
10. Does Atrial rate increase with physiologic stress? 
Yes. 
Recommended mode: DDI Alternate: DDDR 
Comment: The fact that pacing support is required during periods of atrial 
fibrillation indicating that there is some degree of VA block, even if 
only at very rapid atrial rates at which time back-up ventricular pacing 
is required. Thus AAI would not be appropriate in this setting. 
While base rate pacing is all that is required at the time of implantation, 
progression of sinus or AV nodal conduction disease due to intrinsic 
pathologic processes or medications may render the patient 
chronotropically incompetent in the future. Rate modulated capability will 
allow for management of all options. 
Mode Selection Conclusion 20 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
Intermittent. 
7. When is the pacemaker required? 
1. During Atrial fib. 
2. Immediately after conversion (i.e. prolonged Sinus Node recovery time) 
3. During Sinus rhythm due to marked bradycardia 
1 and 2. 
8. Is there a hypertrophied, non-compliant ventricle? 
No. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
No. 
10. Does Atrial rate increase with physiologic stress? 
No. 
Recommended mode: AAIR Alternate: DDIR 
Comment: As the DDD mode tracks endogenous atrial activity, DDDR is the 
optimum mode but only when the MTR and MSR can be independently 
programmed. A low MTR is chosen to minimize the rate increase when in 
atrial fibrillation. During activity, a high MSR allows an appropriate 
increase in rate. In the absence of this capability, choose DDIR. 
While base rate pacing is all that is required at the time of implantation, 
progression of sinus or AV nodal conduction disease due to intrinsic 
pathologic processes or medications may render the patient 
chronotropically incompetent in the future. Rate modulated capability will 
allow for management of all options. 
Mode Selection Conclusion 21 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
Intermittent. 
7. When is the pacemaker required? 
1. During Atrial fib. 
2. Immediately after conversion (i.e. elongated Sinus Node recovery time) 
3. During Sinus rhythm due to marked bradycardia 
3 only. 
8. Is there a hypertrophied, non-compliant ventricle? Yes. 
10. Does Atrial rate increase with physiologic stress? 
No. 
Recommended mode: AAIR Alternate: DDIR 
Comment: Given the hypertrophied, non-compliant ventricle, one wants to 
maintain AV synchrony as much as possible when the atrium is NOT 
fibrillation. Hence VVI and VVIR are not appropriate in this setting. 
Mode Selection Conclusion 22 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
Intermittent. 
7. When is the pacemaker required? 
1. During Atrial fib. 
2. Immediately after conversion (i.e. elongated Sinus Node recovery time) 
3. During Sinus rhythm due to marked bradycardia 
3 only. 
8. Is there a hypertrophied, non-compliant ventricle? 
No. 
9. Is there evidence of pacemaker syndrome (fall in blood pressure, 
retrograde conduction, fall in cardiac output) with ventricular pacing or 
pre-pacing native rhythm when AV synchrony is lost? 
Yes. 
10. Does Atrial rate increase with physiologic stress? 
No. 
Recommended mode: AAIR Alternate: DDIR 
Comment: With documented pacemaker syndrome--whether it be during 
ventricular pacing or its functional equivalent (a junctive rhythm with 
loss of AV synchrony, PVCS: with retrograde conduction) it is essential to 
maintain an appropriate atrio-ventricular contraction sequence 4!. 
Reference 4!: Barold, S. S., "Cardiac Pacing Hemodynamics: The Pacemaker 
Syndrome," Cardio, 1991; (September) 36-51. 
Heldman, D. et al., "True Incidence of Pacemaker Syndrome," Pace, 1990; 13: 
1742-1750. 
Aussbel, U., Furman, S., "The Pacemaker Syndrome, Ann (?) Internal 
Medicine," 1985; 103: 420-429. 
Mode Selection Conclusion 23 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
Intermittent. 
6. Does the Ventricular rate increase with physiologic stress? 
N/A. 
7. When is the pacemaker required? 
1. During Atrial fib. 
2. Immediately after conversion (i.e. elongated Sinus Node recovery time) 
3. During Sinus rhythm due to marked bradycardia 
3 only. 
8. Is there a hypertrophied, non-compliant ventricle? 
No. 
9. Is there evidence of pacemaker syndrome (fall in blood pressure, 
retrograde conduction, fall in cardiac output) with ventricular pacing or 
pre-pacing native rhythm when AV synchrony is lost? 
No. 
10. Does Atrial rate increase with physiologic stress? 
No. 
Recommended mode: VVIR Alternate: DDIR 
Mode Selection Conclusion 24 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
Intermittent. 
7. When is the pacemaker required? 
1. During Atrial fib. 
2. Immediately after conversion (i.e. elongated Sinus Node recovery time) 
3. During Sinus rhythm due to marked bradycardia 
3 only. 
8. Is there a hypertrophied, non-compliant ventricle? Yes. 
10. Does Atrial rate increase with physiologic stress? 
Yes. 
Recommended mode: AAI Alternate: DDI 
Comment: Given the hypertrophied, non-compliant ventricle, one wants to 
maintain AV synchrony as much as possible when the atrium is NOT 
fibrillation. Hence VVI and VVIR are not appropriate in this setting. 
Mode Selection Conclusion 25 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
Intermittent. 
7. When is the pacemaker required? 
1. During Atrial fib. 
2. Immediately after conversion (i.e. elongated Sinus Node recovery time) 
3. During Sinus rhythm due to marked bradycardia 
3 only. 
8. Is there a hypertrophied, non-compliant ventricle? 
No. 
9. Is there evidence of pacemaker syndrome (fall in blood pressure, 
retrograde conduction, fall in cardiac output) with ventricular pacing or 
pre-pacing native rhythm when AV synchrony is lost? 
Yes. 
10. Does Atrial rate increase with physiologic stress? 
Yes. 
Recommended mode: AAI Alternate: DDI 
Comment: With documented pacemaker syndrome--whether it be during 
ventricular pacing or its functional equivalent (a junctive rhythm with 
loss of AV synchrony, PVCS: with retrograde conduction) it is essential to 
maintain an appropriate atrio-ventricular contraction sequence 4!. 
Reference 4!: Barold, S. S., "Cardiac Pacing Hemodynamics: the Pacemaker 
Syndrome," Cardio, 1991; 8: (September) 36-51. 
Heldman, D. et al., "True Incidence of Pacemaker Syndrome," Pace, 1990; 13: 
1742-1750. 
Aussbel, U., Furman, S., "The Pacemaker Syndrome, Ann (?) Internal 
Medicine," 1985; 103: 420-429. 
Mode Selection Conclusion 26 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
Intermittent. 
7. When is the pacemaker required? 
1. During Atrial fib. 
2. Immediately after conversion (i.e. elongated Sinus Node recovery time) 
3. During Sinus rhythm due to marked bradycardia 
3 only. 
8. Is there a hypertrophied, non-compliant ventricle? 
No. 
9. Is there evidence of pacemaker syndrome (fall in blood pressure, 
retrograde conduction, fall in cardiac output) with ventricular pacing or 
pre-pacing native rhythm when AV synchrony is lost? 
No. 
10. Does Atrial rate increase with physiologic stress? 
Yes. 
Recommended mode: VVI Alternate: AAI, DDI 
Mode Selection Conclusion 27 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
Intermittent. 
7. When is the pacemaker required? 
1. During Atrial fib. 
2. Immediately after conversion (i.e. prolonged Sinus Node recovery time) 
3. During Sinus rhythm due to marked bradycardia 
1 and 3. 
8. Is there a hypertrophied, non-compliant ventricle? 
Yes. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
Yes. 
10. Does Atrial rate increase with physiologic stress? 
Yes. 
Recommended mode: DDD Alternate: DDDR 
Comment: As the DDD mode tracks endogenous atrial activity, DDDR is the 
optimum mode but only when the MTR and MSR can be independently 
programmed. A low MTR is chosen to minimize the rate increase when in 
atrial fibrillation. During activity, a high MSR allows an appropriate 
increase in rate. In the absence of this capability, choose DDIR. 
While base rate pacing is all that is required at the time of implantation, 
progression of sinus or AV nodal conduction disease due to intrinsic 
pathologic processes or medications may render the patient 
chronotropically incompetent in the future. Rate modulated capability will 
allow for management of all options. 
Given the hypertrophied, non-compliant ventricle, one wants to maintain AV 
synchrony as much as possible when the atrium is NOT fibrillation. Hence 
VVI and VVIR are not appropriate in this setting. 
The fact that pacing support is required during periods of atrial 
fibrillation indicating that there is some degree of VA block, even if 
only at very rapid atrial rates at which time back-up ventricular pacing 
is required. Thus AAI would not be appropriate in this setting. 
Mode Selection Conclusion 28 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
Intermittent. 
7. When is the pacemaker required? 
1. During Atrial fib. 
2. immediately after conversion (i.e. prolonged Sinus Node recovery time) 
3. During Sinus rhythm due to marked bradycardia 
1 and 3. 
8. Is there a hypertrophied, non-compliant ventricle? 
Yes. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? Yes. 
10. Does Atrial rate increase with physiologic stress? 
No. 
Recommended mode: DDDR 
Comment: Given the hypertrophied, non-compliant ventricle, one wants to 
maintain AV synchrony as much as possible when the atrium is NOT 
fibrillation. Hence VVI and VVIR are not appropriate in this setting. 
Mode Selection Conclusion 29 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
Intermittent. 
7. When is the pacemaker required? 
1. During Atrial fib. 
2. Immediately after conversion (i.e. prolonged Sinus Node recovery time) 
3. During Sinus rhythm due to marked bradycardia 
1 and 3. 
8. Is there a hypertrophied, non-compliant ventricle? 
Yes. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
No. 
10. Does Atrial rate increase with physiologic stress? 
Yes. 
Recommended mode: DDI Alternate: DDIR 
Comment: Given the hypertrophied, non-compliant ventricle, one wants to 
maintain AV synchrony as much as possible when the atrium is NOT 
fibrillation. Hence VVI and VVIR are not appropriate in this setting. 
While base rate pacing is all that is required at the time of implantation, 
progression of sinus or AV nodal conduction disease due to intrinsic 
pathologic processes or medications may render the patient 
chronotropically incompetent in the future. Rate modulated capability will 
allow for management of all options. 
The fact that pacing support is required during periods of atrial 
fibrillation indicating that there is some degree of VA block, even if 
only at very rapid atrial rates at which time back-up ventricular pacing 
is required. Thus AAI would not be appropriate in this setting. 
Mode Selection Conclusion 30 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
Intermittent. 
7. When is the pacemaker required? 
1. During Atrial fib. 
2. Immediately after conversion (i.e. prolonged Sinus Node recovery time) 
3. During Sinus rhythm due to marked bradycardia 
1 and 3. 
8. Is there a hypertrophied, non-compliant ventricle? 
Yes. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
No. 
10. Does Atrial rate increase with physiologic stress? 
No. 
Recommended mode: DDIR 
Comment: As the DDD mode tracks endogenous atrial activity, DDDR is the 
optimum mode but only when the MTR and MSR can be independently 
programmed. A low MTR is chosen to minimize the rate increase when in 
atrial fibrillation. During activity, a high MSR allows an appropriate 
increase in rate. In the absence of this capability, choose DDIR. 
While base rate pacing is all that is required at the time of implantation, 
progression of AV nodal conduction disease due to intrinsic pathologic 
processes or medications may render the patient chronotropically 
incompetent in the future. A DDDR pacemaker will allow for management of 
all options. 
Given the hypertrophied, non-compliant ventricle, one wants to maintain AV 
synchrony as much as possible when the atrium is NOT in fibrillation. 
Hence VVI and VVIR are not appropriate in this setting. 
The fact that pacing support is required during periods of atrial 
fibrillation indicating that there is some degree of VA block, even if 
only at very rapid atrial rates at which time back-up ventricular pacing 
is required. Thus AAI would not be appropriate in this setting. 
Mode Selection Conclusion 31 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
Intermittent. 
7. When is the pacemaker required? 
1. During Atrial fib. 
2. Immediately after conversion (i.e. prolonged Sinus Node recovery time) 
3. During Sinus rhythm due to marked bradycardia 
1 and 3. 
8. Is there a hypertrophied, non-compliant ventricle? 
No. 
9. Is there evidence of pacemaker syndrome (fall in blood pressure, 
retrograde conduction, fall in cardiac output) with ventricular pacing or 
pre-pacing native rhythm when AV synchrony is lost? 
Yes. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
Yes. 
10. Does Atrial rate increase with physiologic stress? 
Yes. 
Recommended mode: DDDR 
Comment: As the DDD mode tracks endogenous atrial activity, DDDR is the 
optimum mode but only when the MTR and MSR can be independently 
programmed. A low MTR is chosen to minimize the rate increase when in 
atrial fibrillation. During activity, a high MSR allows an appropriate 
increase in rate. In the absence of this capability, choose DDIR. 
With documented pacemaker syndrome--whether it being during ventricular 
pacing or its functional equivalent (a junctive rhythm with loss of AV 
synchrony, PVC: with retrograde conduction) it is essential to maintain an 
appropriate atrio-ventricular contraction sequence 4!. 
Reference 4!: Barold, S. S. "Cardiac Pacing Hemodynamics: The Pacemaker 
Syndrome," Cardio, 1991; 8: (September) 36-51. 
Heldman, D. et al., "True Incidence of Pacemaker Syndrome," Pace, 1990; 13: 
1742-1750. 
Aussbel, U., Furman, S., "The Pacemaker Syndrome, Ann (?) Internal 
Medicine," 1985; 103: 420-429. 
Mode Selection Conclusion 32 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
Intermittent. 
7. When is the pacemaker required? 
1. During Atrial fib. 
2. Immediately after conversion (i.e. prolonged Sinus Node recovery time) 
3. During Sinus rhythm due to marked bradycardia 
1 and 3. 
8. Is there a hypertrophied, non-compliant ventricle? 
No. 
9. Is there evidence of pacemaker syndrome (fall in blood pressure, 
retrograde conduction, fall in cardiac output) with ventricular pacing or 
pre-pacing native rhythm when AV synchrony is lost? 
Yes. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
Yes. 
10. Does Atrial rate increase with physiologic stress? 
No. 
Recommended mode: DDDR 
Comment: As the DDD mode tracks endogenous atrial activity, DDDR is the 
optimum mode but only when the MTR and MSR can be independently 
programmed. A low MTR is chosen to minimize the rate increase when in 
atrial fibrillation. During activity, a high MSR allows an appropriate 
increase in rate. In the absence of this capability, choose DDIR. 
With documented pacemaker syndrome--whether it being during ventricular 
pacing or its functional equivalent (a junctive rhythm with loss of AV 
synchrony, PVC: with retrograde conduction) it is essential to maintain an 
appropriate atrio-ventricular contraction sequence 4!. 
Reference 4!: Barold, S. S., "Cardiac Pacing Hemodynamics: the Pacemaker 
Syndrome," Cardio, 1991; 8: (September) 36-51. 
Heldman, D. et al., "True Incidence of Pacemaker Syndrome," Pace, 1990; 13: 
1742-1750. 
Aussbel, U., Furman, S., "The Pacemaker Syndrome, Ann (?) Internal 
Medicine," 1985; 103: 420-429. 
Mode Selection Conclusion 33 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
Intermittent. 
7. When is the pacemaker required? 
1. During Atrial fib. 
2. immediately after conversion (i.e. prolonged Sinus Node recovery time) 
3. During Sinus rhythm due to marked bradycardia 
1 and 3. 
8. Is there a hypertrophied, non-compliant ventricle? 
No. 
9. Is there evidence of pacemaker syndrome (fall in blood pressure, 
retrograde conduction, fall in cardiac output) with ventricular pacing or 
pre-pacing native rhythm when AV synchrony is lost? 
Yes. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
No. 
10. Does Atrial rate increase with physiologic stress? 
Yes. 
Recommended mode: DDI Alternate: DDIR or DDDR 
Comment: As the DDD mode tracks endogenous atrial activity, DDDR is the 
optimum mode but only when the MTR and MSR can be independently 
programmed. A low MTR is chosen to minimize the rate increase when in 
atrial fibrillation. During activity, a high MSR allows an appropriate 
increase in rate. In the absence of this capability, choose DDIR. 
With documented pacemaker syndrome--whether it being during ventricular 
pacing or its functional equivalent (a junctive rhythm with loss of AV 
synchrony, PVC: with retrograde conduction) it is essential to maintain an 
appropriate atrio-ventricular contraction sequence 4!. 
While base rate pacing is all that is required at the time of implantation, 
progression of sinus or AV nodal conduction disease due to intrinsic 
pathologic processes or medications may render the patient 
chronotropically incompetent in the future. Rate modulated capability will 
allow for management of all options. 
Reference 4!: Barold, S. S., "Cardiac Pacing Hemodynamics: The Pacemaker 
Syndrome," Cardio, 1991; 8: (September) 36-51. 
Heldman, D. et al., "True Incidence of Pacemaker Syndrome," Pace, 1990; 13: 
1742-1750. 
Aussbel, U., Furman, S., "The Pacemaker Syndrome, Ann (?) Internal 
Medicine," 1985; 103: 420-429. 
Mode Selection Conclusion 34 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
Intermittent. 
7. When is the pacemaker required? 
1. During Atrial fib. 
2. Immediately after conversion (i.e. prolonged Sinus Node recovery time) 
3. During Sinus rhythm due to marked bradycardia 
1 and 3. 
8. Is there a hypertrophied, non-compliant ventricle? 
No. 
9. Is there evidence of pacemaker syndrome (fall in blood pressure, 
retrograde conduction, fall in cardiac output) with ventricular pacing or 
pre-pacing native rhythm when AV synchrony is lost? 
Yes. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
No. 
10. Does Atrial rate increase with physiologic stress? 
No. 
Recommended mode: DDIR 
Comment: With documented pacemaker syndrome--whether it being during 
ventricular pacing or its functional equivalent (a junctive rhythm with 
loss of AV synchrony, PVC: with retrograde conduction) it is essential to 
maintain an appropriate atrio-ventricular contraction sequence 4!. 
The fact that pacing support is required during periods of atrial 
fibrillation indicating that there is some degree of VA block, even if 
only at very rapid atrial rates at which time back-up ventricular pacing 
is required. Thus AAI would not be appropriate in this setting. 
Reference 4!: Barold, S. S., "Cardiac Pacing Hemodynamics: The Pacemaker 
Syndrome," Cardio, 1991; 8: (September) 36-51. 
Heldman, D. et al., "True Incidence of Pacemaker Syndrome," Pace, 1990; 13: 
1742-1750. 
Aussbel, U., Furman, S., "The Pacemaker Syndrome, Ann (?) Internal 
Medicine," 1985; 103: 420-429. 
Mode Selection Conclusion 35 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
Intermittent. 
7. When is the pacemaker required? 
1. During Atrial fib. 
2. Immediately after conversion (i.e. prolonged Sinus Node recovery time) 
3. During Sinus rhythm due to marked bradycardia 
1 and 3. 
8. Is there a hypertrophied, non-compliant ventricle? 
No. 
9. Is there evidence of pacemaker syndrome (fall in blood pressure, 
retrograde conduction, fall in cardiac output) with ventricular pacing or 
pre-pacing native rhythm when AV synchrony is lost? 
No. 
10. Does Atrial rate increase with physiologic stress? 
Yes. 
Recommended mode: DDI Alternate: DDIR 
Comment: While base rate pacing is all that is required at the time of 
implantation, progression of sinus or AV nodal conduction disease due to 
intrinsic pathologic processes or medications may render the patient 
chronotropically incompetent in the future. Rate modulated capability will 
allow for management of all options. 
The fact that pacing support is required during periods of atrial 
fibrillation indicating that there is some degree of VA block, even if 
only at very rapid atrial rates at which time back-up ventricular pacing 
is required. Thus AAI would not be appropriate in this setting. 
Mode Selection Conclusion 36 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
Intermittent. 
7. When is the pacemaker required? 
1. During Atrial fib. 
2. Immediately after conversion (i.e. prolonged Sinus Node recovery time) 
3. During Sinus rhythm due to marked bradycardia 
1 and 3. 
8. Is there a hypertrophied, non-compliant ventricle? 
No. 
9. Is there evidence of pacemaker syndrome (fall in blood pressure, 
retrograde conduction, fall in cardiac output) with ventricular pacing or 
pre-pacing native rhythm when AV synchrony is lost? 
No. 
10. Does Atrial rate increase with physiologic stress? 
Yes. 
Recommended mode: DDI Alternate: DDIR 
Comment: While base rate pacing is all that is required at the time of 
implantation, progression of sinus or AV nodal conduction disease due to 
intrinsic pathologic processes or medications may render the patient 
chronotropically incompetent in the future. Rate modulated capability will 
allow for management of all options. 
The fact that pacing support is required during periods of atrial 
fibrillation indicating that there is some degree of VA block, even if 
only at very rapid atrial rates at which time back-up ventricular pacing 
is required. Thus AAI would not be appropriate in this setting. 
Mode Selection Conclusion 37 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
None. 
11. What is the status of the sinus rhythm (Neuroregulatory abnormality, 
Normal, Sinus Node dysfunction)? 
Neuroregulatory abnormality. 
Recommended mode: DDI 
Comment: A neuroregulatory abnormality causes syncope by one of two 
mechanisms. It inhibits the cardiac rate (both sinus slowing and AV block) 
and causes vasodilation. Pure cardioinhibitory effects can be treated with 
VVI pacing. More often, there is a combined mechanism at which time the 
vasodilation requires AV synchrony to minimize the hypotensive episodes. 
These patients do not require atrial pacing--hence DDI mode 1!. 
Reference 1!: Fitzpatrick, A. et al., "Dual-Chamber Pacing Aborts 
Vasovagal Syncope Induced by Headup 600 Tilt," Pace 1991; 14: 13-19. 
Mode Selection Conclusion 38 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
None. 
11. What is the status of the sinus rhythm (Neuroregulatory abnormality, 
Normal, Sinus Node dysfunction)? 
Normal. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
No. 
Recommended mode: Reconsider need for pacemaker. 
Comment: Although the initial decision is that the patient required a 
pacemaker, based on the answers, there is no evidence for even 
intermittent sinus node dysfunction or AV block. Unless the pacemaker is 
being implanted prophylactically in which case answer the questions as if 
the reason for the pacemaker were manifest; reconsider the decision for 
permanent cardiac pacing. 
Mode Selection Conclusion: 39 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
None. 
11. What is the status of the sinus rhythm (Neuroregulatory abnormality, 
Normal, Sinus Node dysfunction)? 
Normal. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
Yes. 
8. Is there a hypertrophied, non-compliant ventricle? 
Yes. 
13. Is the sinus rate likely to exceed the maximum tracking rate? 
Yes. 
Recommended mode: DDDR Alternate: DDD 
Comment: Although sinus node function may be normal, if the sinus rate 
exceeds the MTR, the patient may be limited by the loss of appropriate AV 
synchrony during normal upper rate behavior. Choosing DDDR will allow for 
sensor-driven rate smoothing 5!. 
Given the hypertrophied, non-compliant ventricle, one wants to maintain AV 
synchrony as much as possible when the atrium is NOT fibrillation. Hence 
VVI and VVIR are not appropriate in this setting. 
Reference 5!: Higano, S. T., Hayes, D. L., Elsinger, G., "Sensor-Driven 
Rate Smoothing in a DDDR Pacemaker," Pace, 1989; 12: 922-929. 
Mode Selection Conclusion 40 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
None. 
11. What is the status of the sinus rhythm (Neuroregulatory abnormality, 
Normal, Sinus Node dysfunction)? 
Normal. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
Yes. 
8. Is there a hypertrophied, non-compliant ventricle? 
Yes. 
13. Is the sinus rate likely to exceed the maximum tracking rate? 
No. 
Recommended mode: DDD 
Comment: Given the hypertrophied, non-compliant ventricle, one wants to 
maintain AV synchrony as much as possible when the atrium is NOT 
fibrillation. Hence VVI and VVIR are not appropriate in this setting. 
Mode Selection Conclusion 41 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
None. 
11. What is the status of the sinus rhythm (Neuroregulatory abnormality, 
Normal, Sinus Node dysfunction)? 
Normal. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
Yes. 
8. Is there a hypertrophied, non-compliant ventricle? 
No. 
9. Is there evidence of pacemaker syndrome (fall in blood pressure, 
retrograde conduction, fall in cardiac output) with ventricular pacing or 
pre-pacing native rhythm when AV synchrony is lost? 
Yes. 
13. Is the sinus rate likely to exceed the maximum tracking rate? 
Yes. 
Recommended mode: DDDR Patient Disc: 
Comment: With documented pacemaker syndrome--whether it being during 
ventricular pacing or its functional equivalent (a junctive rhythm with 
loss of AV synchrony, PVC: with retrograde conduction) it is essential to 
maintain an appropriate atrio-ventricular contraction sequence 4!. 
Reference 4!: Barold, S. S., "Cardiac Pacing Hemodynamics: The Pacemaker 
Syndrome," Cardio, 1991; 8: (September) 36-51. 
Heldman, D. et al., "True Incidence of Pacemaker Syndrome," Pace, 1990; 13: 
1742-1750. 
Aussbel, U., Furman, S., "The Pacemaker Syndrome, Ann (?) Internal 
Medicine," 1985; 103: 420-429, 
Mode Selection Conclusion 42 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
None. 
11. What is the status of the sinus rhythm (Neuroregulatory abnormality, 
Normal, Sinus Node dysfunction)? 
Normal. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
Yes. 
8. Is there a hypertrophied, non-compliant ventricle? 
No. 
9. Is there evidence of pacemaker syndrome (fall in blood pressure, 
retrograde conduction, fall in cardiac output) with ventricular pacing or 
pre-pacing native rhythm when AV synchrony is lost? 
Yes. 
13. Is the sinus rate likely to exceed the maximum tracking rate? 
No. 
Recommended mode: DDD 
Patient Disc: 
Comment: With documented pacemaker syndrome--whether it being during 
ventricular pacing or its functional equivalent (a junctive rhythm with 
loss of AV synchrony, PVC: with retrograde conduction) it is essential to 
maintain an appropriate atrio-ventricular contraction sequence 4!. 
Reference 4!: Barold, S. S., "Cardiac Pacing Hemodynamics: The Pacemaker 
Syndrome," Cardio, 1991; 8: (September) 36-51. 
Heldman, D. et al., "True Incidence of Pacemaker Syndrome," Pace, 1990; 13: 
1742-1750. 
Aussbel, U., Furman, S., "The Pacemaker Syndrome, Ann (?) Internal 
Medicine," 1985; 103: 420-429. 
Mode Selection Conclusion 43 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
None. 
11. What is the status of the sinus rhythm (Neuroregulatory abnormality, 
Normal, Sinus Node dysfunction)? 
Normal. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
Yes. 
8. Is there a hypertrophied, non-compliant ventricle? 
No. 
9. Is there evidence of pacemaker syndrome (fall in blood pressure, 
retrograde conduction, fall in cardiac output) with ventricular pacing or 
pre-pacing native rhythm when AV synchrony is lost? 
No. 
13. Is the sinus rate likely to exceed the maximum tracking rate? 
Yes. 
Recommended mode: DDDR 
Mode Selection Conclusion 44 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
None. 
11. What is the status of the sinus rhythm (Neuroregulatory abnormality, 
Normal, Sinus Node dysfunction)? 
Normal. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
Yes. 
8. Is there a hypertrophied, non-compliant ventricle? 
No. 
9. Is there evidence of pacemaker syndrome (fall in blood pressure, 
retrograde conduction, fall in cardiac output) with ventricular pacing or 
pre-pacing native rhythm when AV synchrony is lost? 
No. 
13. Is the sinus rate likely to exceed the maximum tracking rate? 
No. 
Recommended mode: DDD 
Mode Selection Conclusion 45 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
None. 
11. What is the status of the sinus rhythm (Neuroregulatory abnormality, 
Normal, Sinus Node dysfunction)? 
Sinus Node dysfunction. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
No. 
10. Does Atrial rate increase with physiologic stress? 
No. 
8. Is there a hypertrophied, non-compliant ventricle? 
Yes. 
14. Is AV node function normal even at higher rates? 
Yes. 
Recommended mode: AAIR 
Comment: Given the hypertrophied, non-compliant ventricle, one wants to 
maintain AV synchrony as much as possible when the atrium is NOT 
fibrillation. Hence VVI and VVIR are not appropriate in this setting. 
Mode Selection Conclusion 46 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
None. 
11. What is the status of the sinus rhythm (Neuroregulatory abnormality, 
Normal, Sinus Node dysfunction)? 
Sinus Node dysfunction. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
No. 
10. Does Atrial rate increase with physiologic stress? 
No. 
8. Is there a hypertrophied, non-compliant ventricle? 
Yes. 
14. Is AV node function normal even at higher rates? 
No. 
Recommended mode: DDIR 
Comment: Given the hypertrophied, non-compliant ventricle, one wants to 
maintain AV synchrony as much as possible when the atrium is NOT 
fibrillation. Hence VVI and VVIR are not appropriate in this setting. 
Mode Selection Conclusion 47 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
None. 
11. What is the status of the sinus rhythm (Neuroregulatory abnormality, 
Normal, Sinus Node dysfunction)? 
Sinus Node dysfunction. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
No. 
10. Does Atrial rate increase with physiologic stress? 
No. 
8. Is there a hypertrophied, non-compliant ventricle? 
No. 
9. Is there evidence of pacemaker syndrome (fall in blood pressure, 
retrograde conduction, fall in cardiac output) with ventricular pacing or 
pre-pacing native rhythm when AV synchrony is lost? 
Yes. 
14. Is AV node function normal even at higher rates? 
Yes. 
Recommended mode: AAIR Patient Disc: 
Comment: With documented pacemaker syndrome whether it being during 
ventricular pacing or its functional equivalent (a junctive rhythm with 
loss of AV synchrony, PVC: with retrograde conduction) it is essential to 
maintain an appropriate atrio-ventricular contraction sequence 4). 
Reference 4): Barold, S. S., "Cardiac Pacing Hemodynamics: The Pacemaker 
Syndrome," Cardio, 1991; 8: (September) 36-51. 
Heldman, D. et al., "True Incidence of Pacemaker Syndrome," Pace, 1990; 13: 
1742-1750. 
Aussbel, U., Furman, S., "The Pacemaker Syndrome, Ann (?) Internal 
Medicine," 1985; 103: 420-429. 
Mode Selection Conclusion 48 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
None. 
11. What is the status of the sinus rhythm (Neuroregulatory abnormality, 
Normal, Sinus Node dysfunction)? 
Sinus Node dysfunction 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
No. 
10. Does Atrial rate increase with physiologic stress? 
No. 
8. Is there a hypertrophied, non-compliant ventricle? 
No. 
9. Is there evidence of pacemaker syndrome (fall in blood pressure, 
retrograde conduction, fall in cardiac output) with ventricular pacing or 
pre-pacing native rhythm when AV synchrony is lost? 
Yes. 
14. Is AV node function normal even at higher rates? 
No. 
Recommended mode: DDIR Patient Disc: 
Comment: With documented pacemaker syndrome whether it being during 
ventricular pacing or its functional equivalent (a junctive rhythm with 
loss of AV synchrony, PVC: with retrograde conduction) it is essential to 
maintain an appropriate atrio-ventricular contraction sequence 4!. 
Reference 4!: Barold, S. S., "Cardiac Pacing Hemodynamics: The Pacemaker 
Syndrome," Cardio, 1991; 08: (September) 36-51. 
Heldman, D. et al., "True Incidence of Pacemaker Syndrome," Pace, 1990; 13: 
1742-1750. 
Aussbel, U., Furman, S., "The Pacemaker Syndrome, Ann (?) Internal 
Medicine," 1985; 103: 420-429. 
Mode Selection Conclusion 49 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
None. 
11. What is the status of the sinus rhythm (Neuroregulatory abnormality, 
Normal, Sinus Node dysfunction)? 
Sinus Node dysfunction. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
No. 
10. Does Atrial rate increase with physiologic stress? 
No. 
8. Is there a hypertrophied, non-compliant ventricle? 
No. 
9. Is there evidence of pacemaker syndrome (fall in blood pressure, 
retrograde conduction, fall in cardiac output) with ventricular pacing or 
pre-pacing native rhythm when AV synchrony is lost? 
No. 
14. Is AV node function normal even at higher rates? 
Yes. 
Recommended mode: AAIR 
Mode Selection Conclusion 50 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
None. 
11. What is the status of the sinus rhythm (Neuroregulatory abnormality, 
Normal, Sinus Node dysfunction)? 
Sinus Node dysfunction. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
No. 
10. Does Atrial rate increase with physiologic stress? 
No. 
8. Is there a hypertrophied, non-compliant ventricle? 
No. 
9. Is there evidence of pacemaker syndrome (fall in blood pressure, 
retrograde conduction, fall in cardiac output) with ventricular pacing or 
pre-pacing native rhythm when AV synchrony is lost? 
No. 
14. Is AV node function normal even at higher rates? 
No. 
Recommended mode: DDIR 
Mode Selection Conclusion 51 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
None. 
11. What is the status of the sinus rhythm (Neuroregulatory abnormality, 
Normal, Sinus Node dysfunction)? 
Sinus Node dysfunction. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
No. 
10. Does Atrial rate increase with physiologic stress? 
Yes. 
8. Is there a hypertrophied, non-compliant ventricle? 
Yes. 
14. Is AV node function normal even at higher rates? 
Yes. 
Recommended Mode: AAI 
Comment: Given the hypertrophied, non-compliant ventricle, one wants to 
maintain AV synchrony as much as possible when the atrium is NOT 
fibrillation. Hence VVI and VVIR are not appropriate in this setting. 
Mode Selection Conclusion 52 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
None. 
11. What is the status of the sinus rhythm (Neuroregulatory abnormality, 
Normal, Sinus Node dysfunction)? 
Sinus Node dysfunction. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
No. 
10. Does Atrial rate increase with physiologic stress? 
Yes. 
8. Is there a hypertrophied, non-compliant ventricle? 
Yes. 
14. Is AV node function normal even at higher rates? 
No. 
Recommended Mode: DDD 
Comment: Given the hypertrophied, non-compliant ventricle, one wants to 
maintain AV synchrony as much as possible when the atrium is NOT 
fibrillation. Hence VVI and VVIR are not appropriate in this setting. 
Mode Selection Conclusion 53 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
None. 
11. What is the status of the sinus rhythm (Neuroregulatory abnormality, 
Normal, Sinus Node dysfunction)? 
Sinus Node dysfunction. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
No. 
10. Does Atrial rate increase with physiologic stress? 
Yes. 
8. Is there a hypertrophied, non-compliant ventricle? 
No. 
9. Is there evidence of pacemaker syndrome (fall in blood pressure, 
retrograde conduction, fall in cardiac output) with ventricular pacing or 
pre-pacing native rhythm when AV synchrony is lost? 
Yes. 
14. Is AV node function normal even at higher rates? 
Yes. 
Recommended mode: AAI Patient Disc: 
Comment: With documented pacemaker syndrome--whether it being during 
ventricular pacing or its functional equivalent (a junctive rhythm with 
loss of AV synchrony, PVC: with retrograde conduction) it is essential to 
maintain an appropriate atrio-ventricular contraction sequence 4!. 
Reference 4!: Barold, S. S., "Cardiac Pacing Hemodynamics: The Pacemaker 
Syndrome," Cardio, 1991; 8: (September) 36-51. 
Heldman, D. et al., "True Incidence of Pacemaker Syndrome," Pace, 1990; 13: 
1742-1750. 
Aussbel, U., Furman, S., "The Pacemaker Syndrome, Ann (?) Internal 
Medicine," 1985; 103: 420-429. 
Mode Selection Conclusion 54 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
None. 
11. What is the status of the sinus rhythm (Neuroregulatory abnormality, 
Normal, Sinus Node dysfunction)? 
Sinus Node dysfunction. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
No. 
10. Does Atrial rate increase with physiologic stress? 
Yes. 
8. Is there a hypertrophied, non-compliant ventricle? 
No. 
9. Is there evidence of pacemaker syndrome (fall in blood pressure, 
retrograde conduction, fall in cardiac output) with ventricular pacing or 
pre-pacing native rhythm when AV synchrony is lost? 
Yes. 
14. Is AV node function normal even at higher rates? 
No. 
Recommended Mode: DDD 
Comment: With documented pacemaker syndrome--whether it being during 
ventricular pacing or its functional equivalent (a junctive rhythm with 
loss of AV synchrony, PVC: with retrograde conduction) it is essential to 
maintain an appropriate atrio-ventricular contraction sequence 4!. 
Reference 4!: Barold, S. S., "Cardiac Pacing Hemodynamics: The Pacemaker 
Syndrome," Cardio, 1991; 8: (September) 36-51. 
Heldman, D. et al., "True Incidence of Pacemaker Syndrome," Pace, 1990; 13: 
1742-1750. 
Aussbel, U., Furman, S., "The Pacemaker Syndrome, Ann (?) Internal 
Medicine," 1985; 103: 420-429. 
Mode Selection Conclusion 55 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
None. 
11. What is the status of the sinus rhythm (Neuroregulatory abnormality, 
Normal, Sinus Node dysfunction)? 
Sinus Node dysfunction 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
No. 
10. Does Atrial rate increase with physiologic stress? 
Yes. 
8. Is there a hypertrophied, non-compliant ventricle? 
No. 
9. Is there evidence of pacemaker syndrome (fall in blood pressure, 
retrograde conduction, fall in cardiac output) with ventricular pacing or 
pre-pacing native rhythm when AV synchrony is lost? 
No. 
14. Is AV node function normal even at higher rates? 
Yes. 
Recommended Mode: AAI 
Mode Selection Conclusion 56 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
None. 
11. What is the status of the sinus rhythm (Neuroregulatory abnormality, 
Normal, Sinus Node dysfunction)? 
Sinus Node dysfunction. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
No. 
10. Does Atrial rate increase with physiologic stress? 
Yes. 
8. Is there a hypertrophied, non-compliant ventricle? 
No. 
9. Is there evidence of pacemaker syndrome (fall in blood pressure, 
retrograde conduction, fall in cardiac output) with ventricular pacing or 
pre-pacing native rhythm when AV synchrony is lost? 
No. 
14. Is AV node function normal even at higher rates? 
No. 
Recommended Mode: DDD 
Mode Selection Conclusion 57 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
None. 
11. What is the status of the sinus rhythm (Neuroregulatory abnormality, 
Normal, Sinus Node dysfunction)? 
Sinus Node dysfunction 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
Yes. 
10. Does Atrial rate increase with physiologic stress? 
No. 
8. Is there a hypertrophied, non-compliant ventricle? 
Yes. 
Recommended Mode: DDDR 
Comment: Given the hypertrophied, non-compliant ventricle, one wants to 
maintain AV synchrony as much as possible when the atrium is NOT 
fibrillation. Hence VVI and VVIR are not appropriate in this setting. 
Mode Selection Conclusion 58 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
None. 
11. What is the status of the sinus rhythm (Neuroregulatory abnormality, 
Normal, Sinus Node dysfunction)? 
Sinus Node dysfunction 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
Yes. 
10. Does Atrial rate increase with physiologic stress? 
No. 
8. Is there a hypertrophied, non-compliant ventricle? 
No. 
9. Is there evidence of pacemaker syndrome (fall in blood pressure, 
retrograde conduction, fall in cardiac output) with ventricular pacing or 
pre-pacing native rhythm when AV synchrony is lost? 
Yes. 
Recommended mode: DDDR 
Comment: With documented pacemaker syndrome--whether it being during 
ventricular pacing or its functional equivalent (a junctive rhythm with 
loss of AV synchrony, PVC: with retrograde conduction) it is essential to 
maintain an appropriate atrio-ventricular contraction sequence 4!. 
Reference 4!: Barold, S. S., "Cardiac Pacing Hemodynamics: The Pacemaker 
Syndrome," Cardio, 1991; 8: (September) 36-51. 
Heldman, D. et al., "True Incidence of Pacemaker Syndrome," Pace, 1990; 13: 
1742-1750. 
Aussbel, U., Furman, S., "The Pacemaker Syndrome, Ann (?) Internal 
Medicine," 1985; 103: 420-429. 
Mode Selection Conclusion 59 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
None. 
11. What is the status of the sinus rhythm (Neuroregulatory abnormality, 
Normal, Sinus Node dysfunction)? 
Sinus Node dysfunction 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
Yes. 
10. Does Atrial rate increase with physiologic stress? 
No. 
8. Is there a hypertrophied, non-compliant ventricle? 
No. 
9. Is there evidence of pacemaker syndrome (fall in blood pressure, 
retrograde conduction, fall in cardiac output) with ventricular pacing or 
pre-pacing native rhythm when AV synchrony is lost? 
No. 
Recommended Mode: DDDR 
Mode Selection Conclusion 60 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
None. 
11. What is the status of the sinus rhythm (Neuroregulatory abnormality, 
Normal, Sinus Node dysfunction)? 
Sinus Node dysfunction. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
Yes. 
10. Does Atrial rate increase with physiologic stress? 
Yes. 
8. Is there a hypertrophied, non-compliant ventricle? 
Yes. 
Recommended Mode: DDD 
Comment Given the hypertrophied, non-compliant ventricle, one wants to 
maintain AV synchrony as much as possible when the atrium is NOT 
fibrillation. Hence VVI and VVIR are not appropriate in this setting. 
Mode Selection Conclusion 61 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
None. 
11. What is the status of the sinus rhythm (Neuroregulatory abnormality, 
Normal, Sinus Node dysfunction)? 
Sinus Node dysfunction. 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
Yes. 
10. Does Atrial rate increase with physiologic stress? 
Yes. 
8. Is there a hypertrophied, non-compliant ventricle? 
No. 
9. Is there evidence of pacemaker syndrome (fall in blood pressure, 
retrograde conduction, fall in cardiac output) with ventricular pacing or 
pre-pacing native rhythm when AV synchrony is lost? 
Yes. 
Recommended Mode: DDD 
Comment: With documented pacemaker syndrome--whether it being during 
ventricular pacing or its functional equivalent (a junctive rhythm with 
loss of AV synchrony, PVC: with retrograde conduction) it is essential to 
maintain an appropriate atrio-ventricular contraction sequence 4!. 
Reference 4!: Barold, S. S., "Cardiac Pacing Hemodynamics: The Pacemaker 
Syndrome," Cardio, 1991; 8: (September) 36-51. 
Heldman, D. et al., "True Incidence of Pacemaker Syndrome," Pace, 1990; 13: 
1742-1750. 
Aussbel, U., Furman, S., "The Pacemaker Syndrome, Ann (?) Internal 
Medicine," 1985; 103: 420-429. 
Mode Selection Conclusion 62 
1. Does the patient need a pacemaker? 
Yes. 
2. Will the patient's need for a pacemaker be infrequent? 
No. 
4. Is the patient mentally incompetent, unaware of surroundings, in need of 
continual nursing care, etc? 
No. 
5. Is there evidence of Atrial fibrillation (None, Chronic, Intermittent)? 
None. 
11. What is the status of the sinus rhythm (Neuroregulatory abnormality, 
Normal, Sinus Node dysfunction)? 
Sinus Node dysfunction 
12. Is AV Block present or is the patient on medications likely to cause AV 
Block? 
Yes. 
10. Does Atrial rate increase with physiologic stress? 
Yes. 
8. Is there a hypertrophied, non-compliant ventricle? 
No. 
9. Is there evidence of pacemaker syndrome (fall in blood pressure, 
retrograde conduction, fall in cardiac output) with ventricular pacing or 
pre-pacing native rhythm when AV synchrony is lost? 
No. 
Recommended Mode: DDD Alternate: DDDR 
Comment: While base rate pacing is all that is required at the time of 
implantation, progression of sinus or AV nodal conduction disease due to 
intrinsic pathologic processes or medications may render the patient 
chronotropically incompetent in the future. Rate modulated capability will 
allow for management of all options.