Source: https://patents.google.com/patent/US7058443?oq=flatulence
Timestamp: 2018-02-26 01:50:01
Document Index: 326115081

Matched Legal Cases: ['art 8', 'art 8', 'art 8', 'art 8', 'art 8', 'art 8', 'art 8', 'art 8']

US7058443B2 - Diagnostic features in biatrial and biventricular pacing systems - Google Patents
Diagnostic features in biatrial and biventricular pacing systems
US7058443B2
US7058443B2 US09842404 US84240401A US7058443B2 US 7058443 B2 US7058443 B2 US 7058443B2 US 09842404 US09842404 US 09842404 US 84240401 A US84240401 A US 84240401A US 7058443 B2 US7058443 B2 US 7058443B2
US09842404
US20020183636A1 (en )
A biatrial and/or biventricular pacing system is used in a diagnostic context. By placing a pacing/sensing lead in three or four chambers of the heart, various conduction sequences can be determined and the originating chamber of various arrhythmias can be identified. This information is stored temporarily in the pacemaker until it is extracted for analysis.
The present invention relates to multi-chamber cardiac pacing systems that utilize pacing/sensing leads in three or four chambers of the heart.
The heart functions by generating an electrical signal to initiate physical contractions of various portions of the heart in a specific and timed sequence. This electrical signal is generated by the sinus node in the upper right atrial wall near the base of the heart and is conducted through the upper heart chambers, i.e., the right and left atria, and causes them to contract in a synchronous manner.
These contractions force the blood contained therein into the right and left ventricles or lower heart chambers. The electrical depolarization wave then travels through and around the ventricles, triggering their contraction, which forces the blood throughout the vascular system. The contraction of the right and left ventricles proceeds in an organized fashion which optimizes emptying of the ventricular chambers.
The synchronous electrical depolarization of the atrial and ventricular chambers can be electrically sensed and displayed, and the electrical waveform is characterized by accepted convention as the “PQRST” complex. The PQRST complex includes the P-wave, corresponding to the atrial depolarization wave, the R-wave, corresponding to the ventricular depolarization wave, and the T-wave which represents the re-polarization of the cardiac cells.
Certain diseases and conduction disturbances can interfere with the natural conduction system of the heart leading to bradycardia or tachycardia of a heart chamber. In short, various chambers of the heart may be caused to contract too early or too late with respect the intended sequence. Thus, synchronicity between the contractions of the atrial chambers or of the ventricular chambers is lost and cardiac output suffers due to the timing imbalance.
Various therapies exist to treat these cardiac deficiencies and arrhythmias. The problem heretofore has been that the cardiac condition has only been diagnosed in general. That is, although the problem has been determined to exist, little additional information has been provided. Such additional information would allow for a more targeted approach to therapy, rather than utilizing the same general therapy in all cases. The problem is further complicated by the fact that these conditions may not occur continuously. Thus, a patient being closely monitored in a hospital may not have the symptoms in question during the monitoring period. Therefore, the inability to monitor and gather information about these conditions, whenever they might occur has hindered the development of targeted therapies.
Table 1 lists a patent that discloses a rate-responsive pacemaker. Unfortunately, the system described by the cited reference lacks features for sensing, recording and utilizing the data obtained through biatrio and/or biventricular pacing systems in a manner to diagnose and more fully appreciate the nature of various cardiac conditions.
U.S. Pat. No. Inventors Title
5,330,513 Nichols et al. Diagnostic Function Data Storage
and Telemetry Out for Rate Responsive
The patent listed in Table 1 above is hereby incorporated by reference herein in its entirety. As those of ordinary skill in the art will appreciate readily upon reading the Summary of the Invention, Detailed Description of the Preferred Embodiments and claims set forth below, the devices and methods disclosed in the patent of Table 1 may be modified advantageously by using the techniques of the present invention.
The present invention has certain objects. That is, various embodiments of the present invention provide solutions to one or more problems existing in the prior art with respect to cardiac pacing and diagnosis in general, and fully understanding and appreciating the specifics and nature of cardiac conditions in patients having implanted cardiac pacemakers in particular. Such problems include, for example, not knowing what the nature of the various conduction pathways within a patient's heart are. Specifically, not knowing or being able to readily determine if dominant abnormal pathways have developed, let alone what they are or what their particular characteristics are. Other problems include not being able to determine the specific localized origin of certain cardiac arrhythmias, thus limiting the options for treatment to more generalized approaches. This, in turn prevents specific and targeted treatments from being implemented.
Various embodiments of the present invention have the object of solving at least one of the foregoing problems. While some pacing systems have been able to sense certain conditions and monitor certain information, such approaches have generally failed to take into account to the overall mapping of specific cardiac events and conditions between the various chambers of the heart. It is therefore another object of the present invention to provide an improved apparatus and methodology for sensing cardiac events, including naturally occurring conductions, paced events, and arrhythmias is sufficient detail to determine their predominate origin and/or pathway in order to fulfill at least one of the foregoing objects.
In comparison to known implementations of cardiac pacing systems and methodologies, various embodiments of the present invention may provide one or more of the following advantages: gathering detailed information about specific parameters of various cardiac conditions and occurrences; storing this information for a period of time so as to gather a representative and illustrative sample; determining the specific pathways, frequency and dominance of cardiac conductions; determining the originating chamber for various cardiac arrhythmias; and providing this information in a manner useful to suggest of implement specific therapies.
Some embodiments of the invention include one or more of the following features: utilizing a biatrio and/or biventricular pacing system in a diagnostic capacity to determine conduction patterns and sequences. For example, the present invention provides for measuring the timing and pathways of various cardiac sequences. This can be accomplished simply by sensing or by pacing and sensing.
Another feature of the present invention is the utilization of biatrio and/or biventricular pacing systems in a diagnostic capacity to determine the origin of various arrhythmias. For example, the present invention can determine the origin of supra ventricular tachycardias, atrial flutter, atrial fibrillation, premature ventricular contractions and ventricular tachycardias, among other conditions.
Another feature of the present invention is the utilization of sensing and pacing leads in two, three or four chambers of the heart. Four-chamber sensing provides for the largest array of diagnostic capabilities. That is, a sensing lead is placed in each atrial chamber and each ventricular chamber. Data can then be obtained and recorded from each of these sensors.
In this manner, the conduction sequences of the heart can be observed over time and this data can be provided to the cardiologist. Atrial to ventricle (and vice versa), atrial to atrial, and ventricular to ventricular conduction and timing can be obtained.
In addition, by monitoring which sensor first detects a particular problem, the origin of various cardiac arrhythmias can be determined. This information will be stored within the pacemaker and provided to the medical professional through telemetry or data transmission mechanisms.
FIG. 1 is a schematic illustration of an implantable medical device within the chest cavity of a patient, adjacent to the patient's heart.
FIG. 2 is a partially sectional perspective view of an implantable medical device coupled to a mammalian heart.
FIG. 4 is a partially sectional perspective view of a multi-lead, multi-chamber implantable medical device.
FIG. 5 is a block diagram of the constituent components of the multi-lead, multi-chamber implantable medical device.
FIG. 6 is a schematic diagram illustrating a four-channel, biatrial/biventricular pacing system.
FIG. 7 is a sample histogram illustrating sensed AV conduction by the pacing system illustrated in FIG. 5.
FIG. 8A is a sample histogram illustrating sensed A—A conduction by the pacing system illustrated in FIG. 5.
FIG. 8B is a sample histogram illustrating sensed A—A conduction that is categorized by timing intervals, as sensed by a pacing system similar to that shown in FIG. 5.
FIG. 9A is a sample histogram illustrating sensed V—V conduction by the pacing system illustrated in FIG. 5.
FIG. 9B is a sample histogram illustrating sensed V—V conduction that is categorized by timing intervals, as sensed by a pacing system similar to that shown in FIG. 5.
FIGS. 10A and 10B are sample histograms illustrating paced V—V conduction and paced and sensed by the pacing system illustrated in FIG. 5.
FIGS. 11A and 11B are sample histograms illustrating a determination of the origin of supra ventricular tachycardias.
FIGS. 12A and 12B are sample histograms illustrating a determination of the origin of atrial flutter or atrial fibrillation.
FIGS. 13A and 13B are sample histograms illustrating a determination of the origin of premature ventricular contractions.
FIGS. 14A and 14B are sample histograms illustrating a determination of the origin of ventricular tachycardia.
FIG. 15 is a flowchart illustrating the process of determining conduction sequences with the pacing system of the present invention.
FIG. 16 is a flowchart illustrating the process of determining the originating chamber of various cardiac arrhythmias with the pacing system of the present invention.
FIG. 1 is a simplified schematic view of one embodiment of implantable medical device (“IMD”) 10 of the present invention. IMD 10 shown in FIG. 1 is a pacemaker comprising at least one of pacing and sensing leads 16 and 18 attached to connector module 12 of hermetically sealed enclosure 14 and implanted near human or mammalian heart 8. Pacing and sensing leads 16 and 18 sense electrical signals attendant to the depolarization and re-polarization of the heart 8, and further provide pacing pulses for causing depolarization of cardiac tissue in the vicinity of the distal ends thereof. Leads 16 and 18 may have unipolar or bipolar electrodes disposed thereon, as is well known in the art. Examples of IMD 10 include implantable cardiac pacemakers disclosed in U.S. Pat. No. 5,158,078 to Bennett et al., U.S. Pat. No. 5,312,453 to Shelton et al. or U.S. Pat. No. 5,144,949 to Olson, all hereby incorporated by reference herein, each in its respective entirety.
As shown in FIG. 3, lead 18 is coupled to node 50 in IMD 10 through input capacitor 52. Activity sensor or accelerometer 11 is most preferably attached to a hybrid circuit located inside hermetically sealed enclosure 14 of IMD 10. The output signal provided by activity sensor 11 is coupled to input/output circuit 54. Input/output circuit 54 contains analog circuits for interfacing with heart 8, activity sensor 11, antenna 56 and circuits for the application of stimulating pulses to heart 8. The rate of heart 8 is controlled by software-implemented algorithms stored microcomputer circuit 58.
IMD 10 is shown in FIG. 4 in combination with leads 1, 7 and 41, and lead connector assemblies 23, 17 and 6 inserted into connector block 12. Optionally, insulation of the outward facing portion of housing 14 of PCD 10 may be provided using a plastic coating such as parylene or silicone rubber, as is employed in some unipolar cardiac pacemakers. The outward facing portion, however, may be left uninsulated or some other division between insulated and uninsulated portions may be employed. The uninsulated portion of housing 14 serves as a subcutaneous defibrillation electrode to defibrillate either the atria or ventricles. Lead configurations other that those shown in FIG. 4 may be practiced in conjunction with the present invention, such as those shown in U.S. Pat. No. 5,690,686 to Min et al., hereby incorporated by reference herein in its entirety.
FIG. 5 is a functional schematic diagram of one embodiment of IMD 10 of the present invention. This diagram should be taken as exemplary of the type of device in which various embodiments of the present invention may be embodied, and not as limiting, as it is believed that the invention may be practiced in a wide variety of device implementations, including cardioverter and defibrillators which do not provide antitachycardia pacing therapies.
Detection of atrial or ventricular tachyarrhythmias, as employed in the present invention, may correspond to tachyarrhythmia detection algorithms known in the art. For example, the presence of an atrial or ventricular tachyarrhythmia may be confirmed by detecting a sustained series of short R-R or P–P intervals of an average rate indicative of tachyarrhythmia or an unbroken series of short R-R or P-P intervals. The suddenness of onset of the detected high rates, the stability of the high rates, and a number of other factors known in the art may also be measured at this time. Appropriate ventricular tachyarrhythmia detection methodologies measuring such factors are described in U.S. Pat. No. 4,726,380 issued to Vollmann, U.S. Pat. No. 4,880,005 issued to Pless et al. and U.S. Pat. No. 4,830,006 issued to Haluska et al., all incorporated by reference herein, each in its respective entirety. An additional set of tachycardia recognition methodologies is disclosed in the article “Onset and Stability for Ventricular Tachyarrhythmia Detection in an Implantable Pacer-Cardioverter-Defibrillator” by Olson et al., published in Computers in Cardiology, Oct. 7–10, 1986, IEEE Computer Society Press, pages 167–170, also incorporated by reference herein in its entirety. Atrial fibrillation detection methodologies are disclosed in Published PCT Application Ser. No. US92/02829, Publication No. WO92/18198, by Adams et al., and in the article “Automatic Tachycardia Recognition”, by Arzbaecher et al., published in PACE, May–June, 1984, pp. 541–547, both of which are incorporated by reference herein in their entireties.
FIG. 6 is a schematic representation of an implanted, four channel cardiac pacemaker for restoring synchronous contractions of the right and left atria and the right and left ventricles. IMD 10 as illustrated in FIG. 6 in similar in structure to that illustrated in FIG. 4. IMD 10 includes an in-line connector plug 23 of right atrium (RA) lead 116 that is fitted into a bipolar bore of connector block 12 and is coupled to a pair of electrically insulated conductors within lead body 41 that are connected with distal tip RA pace/sense electrode 119 and proximal ring RA pace/sense electrode 121. The distal end of the RA lead 116 is attached to the RA wall by a conventional attachment mechanism 117. Bipolar, endocardial right ventricle (RV) lead 132 is passed through the vein into the RA chamber of the heart 8 and into the RV where its distal ring and tip RV pace/sense electrodes 138 and 140 are fixed in place in the apex by a conventional distal attachment mechanism 141. The RV lead 132 is formed with an in-line connector 134 fitting into a bipolar bore of connector block 12 that is coupled to a pair of electrically insulated conductors within lead body 136 and connected with distal tip RV pace/sense electrode 140 and proximal ring RV pace/sense electrode 138.
In this case, a quadripolar, endocardial left ventricle (LV) coronary sinus (CS) lead 152 is passed through a vein into the RA chamber of the heart 8, into the CS and then inferiorly in the great vein to extend the distal pair of LV CS pace/sense electrodes 148 and 150 alongside the LV chamber and leave the proximal pair of left atrium (LA) CS pace/sense electrodes 128 and 130 adjacent the LA. The LV CS lead 152 is formed with a four conductor lead body 156 coupled at the proximal end to a bifurcated in-line connector 6 fitting into a pair of bipolar bores of connector block 12. The four electrically insulated lead conductors in LV CS lead body 156 are separately connected with one of the distal pair of LV CS pace/sense electrodes 148 and 150 and the proximal pair of LA CS pace/sense electrodes 128 and 130.
FIG. 6 is a schematic diagram illustrating IMD 10 as a four-channel, biatrial/biventricular pacing system. The four-channel pacing system illustrated in FIG. 6 or various other three or four-channel pacing systems can be utilized with the present invention. In general, the present invention encompasses sensing events in both atrial and/or both ventricular chambers. This data is then recorded in a suitable memory device, such as random access memory 59. The data may then be exported after a certain period of time (i.e., gathering data over time) or on a real-time basis, e.g., via radio frequency telemetry. This data may then be used to aid the cardiologist in further diagnosing various cardiac conditions.
The following examples present types of data that may be collected and ways of analyzing that data to achieve a useful purpose. It is to be understood that this is not an exhaustive list of the conditions that may be diagnosed, the parameters that may be sensed or the determinations that are made. Data obtained from the pacing system can be organized in various ways. For purposes of illustration, the following examples illustrate data collected over a period of time and presented in various histogram formats. Various other data presentation and modeling techniques may be used equally well.
FIG. 7 is a sample histogram 200 representing sensed AV conduction across multiple chambers. More specifically, histogram 200 represents the number of conduction sequences occurring for a given pathway over the period of time data collection occurs. Bar 205 indicates that 60% of the detected conduction sequences went from the right atrium (A1) to the right ventricle (V1). Bar 210 indicates that 20% of the conduction sequences went from the right atrium (A1) to the left ventricle (V2). Bar 215 indicates that 15% of the conduction sequences went from the left atrium (A2) to the right ventricle (V1), while bar 220 indicates that 5% of the conduction sequences went from the left atrium (A2) to the left ventricle (V2).
This data is obtained through the placement of a lead in each of the right atrium, the left atrium, the right ventricle and the left ventricle. Each event sensed by these leads can be recorded. By comparing the timing of the various events sensed, the conduction pathway can be determined. For example, for A1–V1 sensing, the right atrial lead will sense an event which is later followed by an event being sensed in the right ventricle.
From this data, the cardiologist and/or IMD 10 can determine which pathway is the dominant pathway and the major direction of conductions. Thus, the present invention is useful in diagnosing and defining various conductive disorders, based on what would be an expected conduction sequence for a healthy heart. Of course, the pacemaker would normally only have been implanted in a patient already suffering some cardiac abnormality. This data can either further define the known cardiac condition, or if the pacemaker were implanted for a different reason, identify another condition. In either case, blockages and abnormalities in conductive pathways can now be specifically identified. The therapy delivered to the patient can then be specifically tailored based on the obtained information. For example, the four-channel pacing system can be programmed to account for specific pathways that are blocked in order to achieve a normal rhythm.
More specifically, in a healthy heart one would expect a close distribution (near 50/50) between A1–V1 and A1–V2, as they should be occurring at approximately the same time. When the data indicates some predominance (as illustrated in FIG. 7), the cardiologist can determine that one of the conduction pathways is lagging behind the other. Furthermore, the significant presence of A2–V1 or A2–V2 conductions also indicates a problem or blockage in the primary conductive pathways. Once such a problem has been identified, pacing therapy can be tailored to overcome the problem. That is, the timing of the pacing can be modified so as to stimulate the lagging ventricle more frequently in order to avoid the conduction deficiency. The localization of the problem through the above data allows for a determination of the best chamber to implement the therapy. The therapy can be determined by a cardiologist observing the data, or automatically implemented by IMD 10, once the problem has been appropriately identified.
FIG. 8A is a sample histogram 225 representing sensed atrial conductions. That is, conductions occurring from the right atrium (A1) to the left atrium (A2) can be sensed and vice versa. The histogram simply represents the percentage occurring in one direction versus the other. Bar 230 illustrates the A1–A2 conductions representing 80% of the sensed conductions, while bar 235 illustrates the A2–A1 conductions representing 20% of the sensed conductions.
Normally, this distribution should indicate nearly all A1–A2 conductions. A significant percentage of A2–A1 conductions is indicative of an atrial arrhythmia or an ectopic focus in the left atrium which is functioning as a primary pacemaker, and thus initiating conductions occurring in a direction opposite to that desired. To perform an appropriate therapy, it is desirable to have more information regarding the timing of the conductions as discussed with reference to FIG. 8B.
FIG. 8B also presents a sample histogram 240 indicating sensed A-A conductions. However, histogram 240 provides additional timing data. That is, the data is further broken down into timing ranges. The number and specifics of the timing ranges can be programmed as desired. By way of example, FIG. 8B illustrates conductions occurring in less than 80 ms (blocks 255, 265) and conductions taking longer that 80 ms (blocks 260, 270). Bar 245 represents the sum total of A1–A2 conductions and indicates that 80% (block 260) took longer than 80 ms, while 20% (block 255) took less than 80 ms.
Similarly, bar 250 represents the sum total of A2–A1 conductions. Block 265 indicates that 8% of the conductions took less that 80 ms, while 92% took longer than 80 ms. It should be appreciated that the illustrated histograms are simply one way of presenting the gathered data. It is the data itself, the ability to gather and store that data, and the ability to extract and utilize the data that is important. As indicated above, multiple time ranges could be established to further indicate the timing of the conductions.
Once the timing of the atrial arrhythmia or ectopic focus has been determined, the appropriate therapy can be initiated. To overcome these problems, the atrium is paced at a higher rate (or overdriven) than that determined, in order to establish the proper direction of conduction and regain proper pacemaking performance. Overdrive pacing is well known and is referred to as antitachycardia pacing (ATP). The localization of the problem through the above data allows for a determination of the best chamber to implement the therapy. The therapy can be determined by a cardiologist observing the data, or automatically implemented by IMD 10, once the problem has been appropriately identified.
FIGS. 9A and 9B are similar to 8A and 8B, except that they illustrate histograms 275, 295 that represent conductions occurring from the right ventricle (V1) to the left ventricle (V2) and vice versa. Histogram 275 in FIG. 9A represents the percentage of conductions occurring from V1–V2 (bar 280) versus those traveling from V2–V1 (bar 290).
FIG. 9B represents additional data that categorizes the conductions based on established time ranges. In this example, three time ranges are provided:
Hatched lines=<60 ms
Shaded=60 ms–100 ms
Checkered=>100 ms.
Thus, bar 300 represents the sample V1–V2 conductions. Bar 310 indicates that 8% of the conductions in that direction take less that 60 ms. Bar 315 indicates that 80% of the conductions take between 60–100 ms and bar 320 indicates that 12% take greater than 100 ms. Similarly, bar 295 indicates the breakdown for the V2–V1 conductions. Bar 325 indicates that 60% of the conductions took between 60–100 ms and bar 330 indicates that 40% took greater than 100 ms. In this sample, there were no V2–V1 conductions that fell into the less than 60 ms time range. This data will indicate the primary conductive pathways and the relative timing involved and can indicate the interventricular conduction delay (IVCD). Again, this data is merely illustrative and more time ranges could be accommodated to further isolate the conduction patterns. This data is helpful in that once the conductive disorders are fully understood for a given patient, the appropriate therapy can be tailored.
One would normally expect that the primary conduction sequence would be V1–V2 nearly 100% of the time. Thus, deviations from this norm indicate an arrhythmia or ectopic focus. The therapy would again be the implementation of ATP to regain control of the pacemaking function. The localization of the problem through the above data allows for a determination of the best chamber to implement the therapy. The therapy can be determined by a cardiologist observing the data, or automatically implemented by IMD 10, once the problem has been appropriately identified.
FIGS. 10A and 10B present the same data in two different formats. The data presented represents paced conduction across the ventricular chambers. That is, a pacing signal is initiated in the right ventricle V1 p and then sensed in the left ventricle V2 s, or vice versa. The time between pacing and sensing is monitored and each data point is then stored in the appropriate timing bin. For this example, the timing break down is as follows:
Hatched lines=<100 ms
Shaded=100–150 ms
Checkered=150–180 ms
Vertical lines=>180 ms
Thus, histogram 340 provides bar 345 that indicates the breakdown when the right ventricle (V1p) is paced and the left ventricle senses (V2s). Block 355 indicates that 8% of the conductions took less than 100 ms; block 360 indicates that 16% took between 100–150 ms; block 365 indicates that 68% took between 150–180 ms; and block 370 indicates that 8% took longer than 180 ms. Bar 350 has blocks 375, 380, 385, and 390, respectively, corresponding to the same time ranges and illustrating their respective percentages. Histogram 345 provides the exact same data in a split bar graph.
By measuring the conduction delay in this manner, the predominant interventricular conduction delay (IVCD) can be determined. The number and values of the time ranges can be set as desired in order to give the level of specificity required. Though not separately shown, other paced/sensed data collection protocols could be established. For example, pacing in an atrial chamber could be monitored in a ventricular chamber.
FIGS. 10A and 10B will indicate the timing of a conduction in a specific direction. In other words, the delay, both electrical and mechanical in nature, can be determined in each direction. This will indicate if V1 and V2 are asynchronous. Thus, if conductions in one direction are determined to be too slow, the appropriate therapy will be to pace in the other direction. This is particularly useful data in biventricular pacing where both sides can be stimulated simultaneously in order to achieve cardiac resynchronization. The therapy can be determined by a cardiologist observing the data, or automatically implemented by IMD 10, once the problem has been appropriately identified.
FIGS. 11A and 11B represent sample data collected by the present invention to indicate the origin of supra ventricular tachycardia (sVT) in a patient having the condition and having a biatrial pacing/sensing system implanted. In this case, both atrial leads are capable of sensing. When a sVT is detected, it is noted which atrial lead first senses it. That data is then recorded and over time, histograms 400 and 420 (both illustrating the same data in different ways) can be generated.
For this example, the sVT break down is as follows:
Bar 410=First Sensed in Right Atrium (A1)
Bar 415=First Sensed in Left Atrium (A2)
In FIGS. 11A and 11B, bar 410 represents the sVT's first sensed by the right atrial lead (A1), which in this example represent 92% of the occurrences. Bar 415 indicates that 8% of the sVT's were first sensed by the left atrial lead (A2). Thus, it becomes apparent that in this case the sVT's are predominantly being initiated in the right atrium. Thus, the implanted pacemaker can be configured to optimally recognize and treat this condition or alternative therapies could likewise be optimized.
The data will indicate which chamber the problem is occurring most frequently in. Thus, the appropriate therapy will be to implement ATP. Ideally, with biatrial pacing, ATP will be performed in the chamber initiating the problem. The localization of the problem through the above data allows for a determination of the best chamber to implement the therapy. Additional information (not separately shown) would be useful in this therapy. That is, the frequency or rate of the sVT can be determined through the collection of timing data. This will indicate at what rate IMD 10 needs to overdrive the cardiac pacing system. The therapy can be determined by a cardiologist observing the data, or automatically implemented by IMD 10, once the problem has been appropriately identified.
In a similar fashion, the origin of various other atrial arrhythmias can be determined. FIGS. 12A and 12B, the originating chamber of atrial flutter (AFL) or atrial fibrillation (AF) is determined. For this example, the sensed AFL/AF break down is as follows:
Bar 430=First Sensed in Right Atrium (A1)
Bar 435=First Sensed in Left Atrium (A2)
In histograms 425 and 440, bar 430 indicates the percentage of AFL/AF events first sensed in the right atrium (40%), while bar 435 indicates the percentage first sensed in the left atrium (60%). Thus, the biatrial sensing allows for the determination of the originating chamber of various atrial arrhythmias, which then allows for an optimization of therapy.
Once it has been determined which chamber the AFL/AF is occurring in, the particular therapy can be implemented. For atrial flutters, the first therapy would be to overdrive the chamber. If unsuccessful, the next choice of therapy would be cardioversion. For atrial fibrillation, defibrillation is the appropriate therapy. Again, by targeting the originating chamber, therapy can be delivered to that chamber directly. The localization of the problem through the above data allows for a determination of the best chamber to implement the therapy. The therapy can be determined by a cardiologist observing the data, or automatically implemented by IMD 10, once the problem has been appropriately identified.
Biventricular sensing allows for the determination of the origin of various ventricular arrhythmias. FIGS. 13A and 13B represent sample data indicating which ventricular chamber first sensed a premature ventricular contraction (PVC). That is, by having a sensing lead located both in the right ventricle (V1) and the left ventricle (V2), data is recorded indicating which of these leads first sensed the PVC.
For this example, the sensed PVC break down is as follows:
Bar 460=First Sensed in Right Ventricle (V1)
Bar 470=First Sensed in Left Ventricle (V2)
Histograms 450 and 480 include bar 460 that indicates 24% of the detected PVC's started in the right ventricle, while bar 470 indicates that 76% of the detected PVC's started in the left ventricle. Once it has been determined where the problem is originating, the therapy can be tailored to address it.
This data will help the cardiologist determine the nature of the PVC's that are occurring. If they are fairly infrequent, ATP can be utilized to attempt to solve the problem. If frequent, the data can help the cardiologist locate the ischemia. Once identified, a surgical bypass may be performed to deliver a greater blood flow. Alternatively, local ablation (such as radio frequency or RF ablation) can be performed to destroy the focus that is repetitively firing.
FIGS. 14A and 14B represent sample data determining the origin of ventricular tachycardia (VT). For this example, the sensed VT break down is as follows:
Bar 500=First Sensed in Right Ventricle (V1)
Bar 510=First Sensed in Left Ventricle (V2)
Histograms 490 and 520 represent the same data. Bar 500 indicates that 16% of the sensed VTs started in the right ventricle, while bar 510 indicates that 84% started in the left ventricle. Thus, it is apparent that the VTs for this patient predominantly start in the left ventricle.
This data will indicate which chamber is predominantly having VT's. If they are not too fast, the appropriate therapy will be ATP. If that does not work or is inappropriate the secondary therapy is cardioversion with a triggered electric shock. Of course, by knowing which chamber the problem is originating in, therapy can be delivered directly to that chamber (or to both with biventricular pacing). The therapy can be determined by a cardiologist observing the data, or automatically implemented by IMD 10, once the problem has been appropriately identified.
The present invention can utilize biatrial and/or biventricular sensing and/or pacing leads on an IMD 10 to gather information relating to the patient's cardiac condition. This data is generally stored within a memory of the IMD 10 and later extracted for analysis. The above description provides sample data for some of the conditions, indications and situations determinable with this configuration. These examples are not meant to be exhaustive or limiting. In addition to gathering data, particular therapies can be determined and implemented by a medical professional, and in some case automatically implemented by IMD 10. Such therapies can include surgical ablation, surgical bypass, ATP, cardioversion and defibrillation.
FIG. 15 is a flowchart illustrating how IMD 10 can be utilized to determine and react to various conduction sequences. As explained above, the originating and receiving chambers of each conduction can be determined and this information can be recorded for subsequent use. The conductions can occur naturally or can be the result of pacing. In either case, a conduction occurs (600) within the patient's heart 8. That conduction will be sensed by a first lead (610). Alternatively at (610), the first lead could initiate the conduction via pacing rather than first sensing a natural conduction. Some time later, a second lead in a different chamber will sense the same conduction. (620). If this is a natural conduction, the originating chamber is determined (630) based on which lead first senses the event. This information will already be known in the pacing context. The receiving chamber is also determined (650) based on which lead subsequently senses the conduction. This data is then recorded (660) in memory within IMD 10.
In some cases, this is all the information that is required. That is, this will indicate the number of conductions occurring from one chamber to another. As explained above, this can include atrial to ventricular, atrial to atrial, and ventricular to ventricular. However, in some contexts it may also be desirable to know the timing of the measured conductions. Thus, the time interval between when the first lead senses (or paces) the conduction and when the second lead senses that conduction is measured (640). This timing data is also recorded (660).
When desired, the recorded data is output (670) through telemetry or other appropriate mechanisms so that it can be analyzed by the cardiologist. The above described histograms represent one format in which the data can be presented to illustrate the conductions that have been recorded.
If appropriate, particular therapies can be identified (680) and applied (690) to the patient based on the recorded data. This can either occur through the implementation of a specific therapy as prescribed by a cardiologist (or other medical professional) analyzing the output data, or it can be a therapy determined by and delivered by IMD 10 based on protocols stored therein.
FIG. 16 is a flowchart illustrating how IMD 10 can determine and react to various cardiac arrhythmias. At some point in time, a cardiac arrhythmia occurs (700). Examples of the types of arrhythmias sensed would include supra ventricular tachycardias, atrial flutter, atrial fibrillation, premature ventricular contractions or ventricular tachycardias. When an arrhythmia occurs, it is sensed by IMD 10 (710). Because IMD 10 has sensing/pacing lead located in three or four of the chambers, the chamber within which the arrhythmia originated in can be determined (720). This is done by identifying which lead first sensed the arrhythmia. This data is them recorded in memory (730). The data can be output (740) and analyzed by a cardiologist, as described above. The data may simply be informative, or it may indicate that a particular therapy should be applied. The appropriate therapy is determined (750) and applied (760), as described above. This can be done by the cardiologist. Alternatively, where appropriate, the data may indicate that IMD 10 should deliver a specific therapy immediately or as a course of regular treatment. For example, should an AFL/AF be detected, IMD 10 could react by delivering antitachycardia pacing, a cardioversion shock or defibrillation, as appropriate.
The preceding specific embodiments are illustrative of the practice of the invention. It is to be understood, therefore, that other expedients known to those skilled in the art or disclosed herein may be employed without departing from the invention or the scope of the claims. For example, the present invention is not limited to sensing or determining the origin of specific conditions or indicators. Rather, the present invention can be employed to gather a wide variety of different types of information on any number of conditions or indicators. The present invention further includes within its scope methods of making and using biatrial and/or biventricular sensing and/or pacing configurations with data collection, as described hereinabove.
1. A method of utilizing a biventricular pacing system to determine the distribution of ventricle to ventricle conduction sequences in a patient having a conductive disorder, the method comprising:
placing sensing leads in both ventricular chambers;
sensing conduction sequences occurring from one ventricular chamber to another ventricular chamber;
determining which ventricular chamber the conduction sequence originated in and which ventricular chamber it propagated to;
recording the determining information in a memory such that the information can be used to identify the relative distribution of conduction sequences;
identifying a conductive disorder in response to the determined relative distribution; and
adjusting a therapy delivered by the pacing system in response to the identified conductive disorder, wherein the conductive disorder comprises a conductive disorder amenable to termination via anti tachycardia pacing (ATP) therapy delivery and wherein the therapy comprises ATP therapy and the adjusting further comprises: initiating the ATP therapy in the ventricular that one of: initiated a recent ventricular depolarization and initiated a majority of ventricular depolarizations over a predetermined time period.
measuring the temporal dimension from the beginning to the conclusion of a plurality of prior conductive sequences; and
storing the measured information in the memory by a range of said temporal dimensions so that the measured information can be utilized to select and adjust the anti tachycardia pacing therapy based on at least one recently measured temporal dimension.
3. The method of claim 2, wherein each measured conductive sequence increments a unit counter representing one of a plurality of temporal dimensions.
pacing one ventricular chamber in order to generate a conductive sequence.
5. A biventricular pacing system for determining the distribution of conduction sequences from a first ventricle (V1) to a second ventricle (V2) in a patient having a conductive disorder, comprising:
sensing means located in both ventricular chambers (V1,V2) for sensing conduction sequences occurring from one ventricular chamber to another ventricular chamber;
means for determining which ventricular chamber the conduction sequence originated in and which ventricular chamber it propagated to;
means for recording the determined information in a memory such that the information can be used to identify the relative distribution of conduction sequences; and
means for detecting an arrhythmia susceptible to termination via anti tachycardia pacing (ATP) therapy and adjusting the ATP therapy based at least in part upon the ventricular chamber the arrhythmia originated in.
6. The biventricular pacing system of claim 5, further comprising:
means for measuring the timing of each conductive sequence and including the measured timing information in the memory to identify relative timing information correlated to the distribution of the conduction sequences.
7. The biventricular pacing system of claim 6, wherein each measured conductive sequence increments a counter representing one of a plurality of discrete time ranges indicative of the timing of the conductive sequence.
8. The biventricular pacing system of claim 6, further comprising:
means for pacing one ventricular chamber in order to generate a conductive sequence.
9. The biventricular pacing system of claim 8, wherein each measured conductive sequence is caused to increment a counter representing one of a plurality of time ranges indicative of the timing of the paced conductive sequence.
10. The biventricular pacing system of claim 5, further comprising:
means for delivering anti tachycardia pacing in response to the determined information, wherein the determined information includes arrthymia propagation information.
11. A biventricular pacing system according to claim 10, wherein said arrthymia propagation information includes at least one of the following characteristics: an arrhythmia type, an arrhythmia-propagation interventricular direction code (e.g., “V1–V2” or “V2–V1”).
12. A biventricular pacing system according to claim 11, wherein said arrhythmia type includes a ventricular fibrillation code.
13. A biventricular pacing system according to claim 11, wherein said arrhythmia type includes a ventricular tachycardia code.
14. A biventricular pacing system according to claim 11, wherein said arrhythmia type includes a pre-ventricular contraction (PVC) code.
15. A biventricular pacing system according to claim 11, wherein said arrhythmia type includes an ectopic foci code.
16. A biventricular pacing system according to claim 11, wherein the arrhythmia-propagation interventricular direction code is used to determine in which ventricle the anti tachycardia pacing is initiated.
17. A biventricular pacing system according to claim 10, wherein arrhythmia propagation interventricular direction (e.g., “V1–V2” or “V2–V1”) further comprises a histogram of at least one prior arrhythmia episode.
18. A biventricular pacing system according to claim 10, wherein said anti tachycardia pacing (ATP) comprises one of a first delivery of ATP and a second delivery of ATP.
US09842404 2001-04-26 2001-04-26 Diagnostic features in biatrial and biventricular pacing systems Active US7058443B2 (en)
US09842404 US7058443B2 (en) 2001-04-26 2001-04-26 Diagnostic features in biatrial and biventricular pacing systems
PCT/US2002/009895 WO2002087695A1 (en) 2001-04-26 2002-03-29 Diagnostic features in biatrial and biventricular pacing systems
US20020183636A1 true US20020183636A1 (en) 2002-12-05
US7058443B2 true US7058443B2 (en) 2006-06-06
ID=25287213
US09842404 Active US7058443B2 (en) 2001-04-26 2001-04-26 Diagnostic features in biatrial and biventricular pacing systems
US (1) US7058443B2 (en)
WO (1) WO2002087695A1 (en)
US7181282B1 (en) 2004-06-14 2007-02-20 Pacesetter, Inc. Implantable cardiac device with PVC density monitoring, and therapy control and method
WO1997044090A1 (en) 1996-05-22 1997-11-27 Sulzer Intermedics Inc. Dual chamber pacing with interchamber delay
WO2000074552A2 (en) 1999-06-08 2000-12-14 Impulse Dynamics N.V. Method for determinig alert window parameters for etc signal delivery
EP1075308A1 (en) 1998-04-28 2001-02-14 Medtronic Inc. Multiple channel, sequential, cardiac pacing systems
"Onset and Stability for Ventricular Tachyarrhythmia Detection in an Implantable Pacer-Cardioverter-Defibrillator" Olson et al., Computers in Cardiology, Oct. 7-10, 1986, IEEE Computer Society Press, pp. 167-170.
PCT, International Search Report, PCT/US/ 02/09895 (Mar. 29, 2002).
WO2002087695A1 (en) 2002-11-07 application
US20020183636A1 (en) 2002-12-05 application
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:STRUBLE, CHESTER;REEL/FRAME:012100/0520