Abstract:
An implantable medical device (IMD) comprises a transmitting/receiving (T/R) device for transmitting medical data sensed from a patient to, and for receiving control signals from, a medical expert (a human medical professional and/or a computerized expert system) at a remote location; an electronic medical treatment device for treating the patient in response to control signals applied thereto; and a sensor circuit, having a sensor circuit output, for producing sensor circuit output signal(s) representing medical data sensed from the patient. The IMD also includes logic device which analyzes the sensor circuit output signal(s) to detect a medical abnormality and either sends a notification signal as well as signal(s) representing a medical state of said patient to the medical expert at the remote location or sends a local treatment device control signal to the medical treatment device, or does both.

Description:
CROSS REFERENCE TO RELATED PATENTS AND APPLICATIONS 
     This application claims priority from Provisional Application No. 60/930,525 filed May 17, 2007. 
     The subject matter of this application is related to that of U.S. patent application Ser. No. 10/460,458, now U.S. Pat. No. 7,277,752, and U.S. patent application Ser. No. 11/502,484 which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     An early generation of implantable cardioverter-defibrillators, “ICDs” had one programmable function: on and off. The modern version of the device has dozens of programmable parameters. In fact, it is now not uncommon for physicians who regularly use such devices to not be fully versed in all of the possible programming complexities of the devices that they implant. Furthermore, the optimal value of some programmable parameters can not be know at the time of device implantation. Physicians will not uncommonly guess at the values to be programmed for anti-tachycardia pacing, because they may not be able to accurately reproduce the tachycardia that a patient may later have. It is therefore not uncommon for physicians to reprogram such parameters, weeks, months or years later, after the occurrence of the actual event showed that they had not guessed well. Occasionally, the examples are striking. A patient, for example with an ICD and both ventricular tachycardia and atrial fibrillation may get not just one but quite a few inappropriate defibrillator shocks, because of an inappropriately selected programmed rate cutoff, stability parameter, etc. The opposite sort of phenomenon may also occur. For example, a patient with known ventricular tachycardia, “VT”, at 200 beats per minute, “bpm”, may have the VT detect rate of an ICD programmed to 180, and may later collapse because of an unexpected episode of VT below the rate cutoff. 
     Occasionally, the malfunctioning of an implanted device can have very serious consequences. The Ventritex V-110 defibrillator at one point had a failure mode which resulted in the sudden death of at least one patient. The “fix” for it, was a programming fix, wherein the downloading of certain instructions prevented the device from being subject to this malfunction. 
     The explosive growth of modern communication systems allows for the possibility of remote supervision and management of implantable devices, and addressing of the aforementioned problems. An ICD which may be providing numerous inappropriate shocks over a short time period—either due to device malfunction, lead malfunction or inappropriate programming of a properly functioning system, could be remotely identified and reprogrammed, for example. 
     A variety of other devices which perform critical functions which remote control could enhance. These include cardiac pumps, insulin pumps, brain stimulating devices and others. 
     There are certain requirements that must be fulfilled if some of the autonomy of device function is to be impinged on. Remote control over a faulty communication link could create problems instead of solving them, so reliability of communications, careful communication monitoring, redundancy and contingency planning, are all features of a remotely controllable implantable device. Since the communication process uses battery power, judicious power management is also a necessity. 
     SUMMARY OF THE INVENTION 
     Hereinbelow: Medical Expert, “ME”, refers to either a person (a “medical professional”) or an expert computational system. 
     The inventions disclosed herein concern methods and apparatus for remotely controlling implantable medical devices such as ICDs, pacemakers, drug infusion pumps, brain stimulators etc. In order to conserve battery power, the communication link between the device and a medical expert is designed to function only when needed. Such need is defined by preprogramming certain notification criteria, such that the device initiates communication with a ME only when the assistance of that ME may be needed. Following notification the ME may observe the sensor information that the device observes in making a device management decision. Furthermore, the ME may have access to additional information e.g. historical information within the device memory, historical information about the particular patient from one or more accessible databases, and information about a plurality of patients with the device from still other databases. The ME may have a variety of control-sharing relationships with the implanted device ranging from complete control (with simultaneous complete inhibition of internal control circuits), or a sharing arrangement in which, for example, both the ME and the control circuits of the IMD may be able to influence treatment. Following such an encounter, the ME may modify the device functioning by reprogramming a number of parameters (e.g. notification parameters, a value of one or more parameters which define a threshold for treatment, the actual treatment parameters, battery management, and the nature of the control-sharing arrangement for future episodes involving notification). 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a representational block diagram of an implantable medical device (“IMD”) which may be remotely controlled. 
         FIG. 2A  is a representational block diagram of a system including an IMD, a sensor and a remote station to be operated by a human medical expert. 
         FIG. 2B  is a representational block diagram of a system including an IMD, a sensor and a remote station operated by a medical expert computational device. 
         FIG. 2C  is a representational block diagram of a system including an IMD, a sensor and a remote station operated by a computational device and a further remote station operated by a human medical expert. 
         FIG. 3A  is a flow diagram of a communication routine for a remotely controllable IMD. 
         FIG. 3B  is a flow diagram of a communication routine for a remote station which communicates with a remotely controllable IMD. 
         FIG. 4A  is a representational block diagram showing remotely controlled power management for a remotely controllable IMD with one battery. 
         FIG. 4B  is a representational block diagram showing locally controlled power management for a remotely controllable IMD with one battery. 
         FIG. 4C  is a representational block diagram showing remotely controlled power management for a remotely controllable IMD with two batteries. 
         FIG. 4D  is a representational block diagram showing locally controlled power management for a remotely controllable IMD with two batteries. 
         FIG. 5  shows a graphic representation of some possible arithmetic relationships illustrating the notification definition and the parameter abnormality definition. 
         FIG. 6A  shows a flow diagram of one possible algorithm for notification. 
         FIG. 6B  shows another flow diagram of one possible algorithm for notification. 
         FIG. 6C  shows another flow diagram of one possible algorithm for notification. 
         FIG. 6D  shows another flow diagram of one possible algorithm for notification. 
         FIG. 7  shows a representational block diagram of a communications relay and its links to an IMD and a remote station 
         FIG. 8  show an overview of one approach to ICD management. 
         FIG. 9  shows a representational diagram of communication with multiple relays. 
         FIG. 10  shows a representational diagram of ICD communication via a personal communication device. 
         FIG. 11  shows a flow diagram of an ICD management algorithm allowing remote notification and management. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  shows an implantable medical device  10  which has the capacity to notify a remotely located medical expert. Sensor circuit  12 , with output  14 , outputs sensor circuit output signals  15 . The signals contain data regarding the measurement of at least one medical parameter, a parameter which allows the logic device  16  of the IMD to make treatment decisions.  15  may be an analog signal or a digitized one, as is known in the art. Means for amplification, of  15  and other techniques for signal management as are known in the art, may reside within  12 . The sensor circuit is coupled to a sensor, as discussed hereinbelow. 
     Logic device  16  analyzes signals  15  to determine if there is a need for (a) treatment of a medical abnormality, and/or (b) notification of a remotely located medical expert. Scenarios are possible in which: 
     1) the abnormality which calls for notification is the same as that which call for treatment; 
     2) the abnormality which calls for notification is less severe than that which requires treatment; 
     3) the abnormality which calls for notification is more severe than that which requires treatment; and 
     4) the abnormality which calls for notification is different than that which requires treatment. 
     By way of example: In the case of 2) and 4) hereinabove, there may be abnormalities which, though not severe enough to always require treatment, might require treatment under certain circumstances which are apparent to an expert person or system. Thus, providing an ICD shock for VT with a rate of over 240 bpm would be likely to represent sound management much of the time, but the desirability of providing an ICD shock for VT at 140 bpm will depend on a variety of circumstances. Some of these may be easily programmed, such as the duration of the event VT. But others may not. If the ICD in the example was connected to multiple sensors, then a complex decision based on the patient&#39;s blood pressure, respiratory rate, and even recent medical history and/or response to antitachycardia pacing in the past might all be factors that would be advisably considered in making a shock/no shock decision. In the case of therapy decision making based on multiple sensors, it becomes impossible to simply say that on set of abnormalities is more severe than another, and “different” is the appropriate term. Thus a VT rate of 140 and a blood pressure of 80 systolic may or may not be considered more severe than a situation with VT at 240 and a blood pressure of 90. Clearly, as the number of different types of sensors increases, and treatment decisions must be based on the data from each of them, algorithms will be more difficult to design, and there will be decreasing likelihood that such algorithms can match the decision making ability of a medical expert, “ME” (person or computational system). The value of having the device “seek consultation” with a ME under these circumstances is clear. At times, the blending of information from multiple sensors may be best accomplished using mathematical techniques which are beyond the scope of a routinely implanted device. Ultimately, treatment decisions may be based on complex functions of multiple parameters and time. Note is made of the fact that these functions may not meet all of the formal mathematical criteria of a function, since input data may not be continuous in nature. 
     By way of yet another example: It may be desirable to notify and ME only in cases of extreme abnormality, and to omit such notification for routine treatments. In such a circumstance,  16  could be operative to treat non-severe abnormalities without notification and to notify a ME for very severe ones. It could be further operative to treat the severe ones unless, having been notified of a severe event, a ME chooses to override the decision of a MP. Thus a single episode of VT at 240 beats per minute might be treated with a shock without notification of an ME, but four episodes of the same VT over 15 minutes might warrant notification. 
     Device  16  may be a microprocessor, a group of microprocessors or other computational devices as is known in the art. When preset criteria for ME notification have been met, it signals a ME by sending notification signal  18  to first transmitting/receiving device. “first T/R”  20 , which is transmitted to the ME.  20  may consist of a single unit which performs both transmitting and receiving functions, or separate units. The transmission methods are discussed hereinbelow. Along with the notification signal, the logic device will send medical data  32  for the ME to evaluate. The data may include (a) actual signals  15 , (b) a processed form of  15 , e.g. filtered, compressed, etc., (c) a further refined form of  15  [e.g. beat to beat measurements of cardiac RR intervals], and (d) still further refined forms of data [e.g. the information that 17 of the last 20 beats were at a rate greater than 200]. 
     The ME has a variety of options upon receipt of this information, discussed hereinbelow. If the ME chooses to treat, a real time remote control signal  22  is received by  20  and sent to  16 . The logic device is operative to pass two types of control signals to the medical treatment device which it controls, (a) remote signals  24  which initially originate with the ME, and (b) local signals  28  generated by the logic device, based on its analysis of  15 . 
     The logic device may prioritize among ME control signals  22  and its own control signals in a variety of ways: 
     a) It may always give priority to ME control signals over its own internally generated control signals; In such a situation, following notification, only the loss of communication with the MP would result in local control (i.e. control of the 
     b) In the presence of ME control signals, it may not even generate its own control signals; 
     c) It may always provide therapy unless there is a specific signal  22  which inhibits its providing therapy; 
     d) It may provide therapy along with the ME in an “OR” logic fashion, such that either one may cause  16  to cause  26  to treat. 
     Memory device  17  is linked to the logic device. It may be used for the storage of information about patient events, the storage of programs for medical treatment device management and sensor signal processing, the temporary storage of information during a communication exchange with a ME, the storage of write-once-only information, and the storage of rules for notification management. 
       FIG. 2A  shows an embodiment of the invention in which IMD  10  communicates through it first T/R, with a second T/R device  40 .  40  provides signals representing a medical state of a patient  42  to be displayed on display device  44 . First input device  46  allows an ME to send real time remote control signals to  40 , for transmission to  20 .  10  and at least one sensor  34  is implanted inside the body of a patient  36 . Examples of possible sensors include a pacemaker wire (for sensing cardiac electrograms), a defibrillator lead, a transducer for measuring glucose concentration, a system of conductors for measuring transthoracic impedance, etc. In the embodiment of the invention shown in  FIG. 2A , sensor information from  34  is coupled to the sensor circuit  38 . IMD  10  transmits the information representing the sensor information (which may be the actual sensor information) via  20  to  40 , for display by  44 . A human ME may then determine the appropriate treatment, and input it to  46 . Signals  48  representing the treatment are transmitted from  40  to  20 , thereby to affect the function of  10 . 
       FIG. 2B  shows an embodiment of the invention in which the ME is a medical expert program or group of programs which run on a computational device  50 . Each of the signals to and from the first T/R ( 18 ,  22  and  32  in  FIG. 1 ) are transmitted between first T/R device  20  and the 2 nd  T/R of shown herein  52 . A device such as  50  would have advantages over the logic device of the IMD including: (a) a much larger memory capacity, such that information may be stored concerning (i) other medical data from this patient; (ii) other medical data from other patients with a similar condition, (iii) performance data about IMD  10 ; (b) ability to update the database for  52  easily and frequently; and (c) ability to update the algorithms run by  50  easily and frequently. 
       FIG. 2C  shows an embodiment of the invention in which IMD  10  in patient  36  communicates with a computer ME  60 , which in turn communicates with a human-based ME  70 . First communication device  62  in  60  communicates with second communication device  72  in  70 ; the communication may be either wireless, indicated by signals  66  or wired, indicated by signals  64 . The function of  74  is analogous to that of  44  in  FIG. 2A , and the function of  76  is analogous to that of  46  in  FIG. 2A . The route of the human real time remote control signal is from  76  to  72  to  62  to  63  to  61  to  11  to  10 . In an alternate embodiment, the human control signal could be coupled from  62  directly to  61 . In yet another embodiment, an RF signal from  72  could be sent directly to  11 . The human ME may use each of the following in the process of making a decision: (a) signals (processed and unprocessed) from one or more sensors  35  in patient  36 , (b) signals indicating the analysis by the logic device of IMD  10 , and (c) signals indicating the analysis by expert logic device  63 . There are numerous possible relationships between which determine dominance, in terms of control, among each of (i) the human ME, (ii) device  63 , and (iii) the IMD logic device. For example: 
     a) in one embodiment of the invention, human ME signals, if received by the logic device of IMD  10  take precedence over control signals which may have been generated by the IMD logic device and over control signals generated by the analysis of the medical data by  63 ; 
     b) in another embodiment, the human may be overruled if both  63  and the IMD logic device disagree with the human; 
     c) in another embodiment, an “OR” logic prevails, and any one of the IMD logic device,  63  or the human ME may cause therapy to be delivered; 
     d) in another embodiment, “AND” logic prevails, and therapy is delivered only if each of the human and  63  and the IMD logic device indicate that treatment is desirable; and 
     e) in another embodiment, any two of the three of the human ME,  63  and the IMD logic device will dominate. 
     To reliably maintain a system in which the control of an implanted medical device is shared or given over to an outside agent, all possible means to maintain communications integrity must be undertaken. Techniques for improving reliability include but are not limited to: (a) redundant communications, (b) the ability to change a route (e.g. wired vs. wireless [though at some point there must be a wireless segment for the implanted device), (c) the ability to change a communications mode (e.g. different means of signal encoding, as is known in the art), (d) the ability to change power output of an RF or other electromagnetic device, (e) the ability to change the sensitivity of a receiver, and (f) the ability to change frequency or channel or telephone number or internet provider. 
     Furthermore, it is important that each of the communicating agents be able to determine whether each segment of the communication path (in each direction) is operative, on a real time basis. For example, if the IMD logic device determines that there has been a break in communication with the ME, it must immediately (a) revert to autonomous operation, and (b) take whatever corrective means it can to restore proper communication. Thus, one embodiment of the invention is operative to cause immediate restoration of device control by the IMD logic device, in the event of a break in communications. To accomplish this, a handshaking routine is operative.  FIG. 3A  shows the routine at the IMD, and  FIG. 3B  shows it at the remote station. (Hereinbelow, communication between the IMD and the remote station through one or more relay devices is described. Handshaking routines, known in the art, are possible between (a) each ‘adjacent’ communicating component in a string of devices, as well as (b) an overall handshake between the remote station and the IMD. 
     Referring to  FIG. 3A , which shows one possible semi-continuous handshaking routine at the IMD, following the transmission of notification signal  100  by the IMD, an interval of time measured by clock  102  is allowed to elapse, waiting for a response, in the form of a remote station handshake signal. If the remote station handshake signal is received in a timely manner, block  104  leads to blocks  106  (resulting in the transmission of an IMD handshake signal by the IMD) and  108 , a declaration of the presence of proper communications. The presence of proper communications allows for a second IMD operating mode, in which the IMD is controlled remotely. Block  106  leads to another waiting period determined by  102 . In the presence of proper communications, the flow diagram will continuously cycle from  102  to  104  to  106  to  102  . . . . However, if there is an interruption in communications, such that a remote station handshake signal is either not received, or not received in a timely manner, block  104  leads to  112  and the declaration of the absence of proper communications.  112  leads to  114  and a first IMD operating mode. In the first operating mode, the IMD is controlled only by the IMD logic device. In this case,  104  also leads to  116 , which lists a menu of options directed at restoring proper communication including: (a) repeat transmission of the remote station handshake signal without any other change; (b) change in either mode, route, power or channel/frequency, (c) change in the sensitivity, selectivity or other receiver characteristics of the IMD receiver (not listed in the figure), (d) change in the characteristics or choice of an upstream communications relay unit (see below), etc. Each of these choices then leads to another handshake attempt, and another waiting for a response. 
     It may be possible to determine whether a break in communication occurred in the IMD to remote station direction, or in the reverse direction by the sending and receiving “communication failure” signals. Thus if the IMD receives  118  a second communication failure signal, it implies that the remote station to IMD leg is intact, and it is the IMD to remote station leg that has failed. This helps direct remedial action. Among the items in menu  116  is the sending of a first communication failure signal, to allow the remote station to gain some diagnostic information about the source of the handshake interruption. 
       FIG. 3B  shows one possible version of a handshaking routine at the remote station. Although the determination of a break in communication is far more important at the IMD end (i.e. so that the IMD may resume autonomous function immediately), there are remedial actions that can be accomplished at the remote station end, therefore making the detection of a handshake interruption valuable at that end as well. At block  150 , the notification signal is received from the IMD, leading to the transmission of a remote station handshake signal at  152 . If after a suitable delay measured by clock  154 , there is no received IMD handshake,  156  leads to  158 , with a menu of remedial options which are analogous to those in block  156 . The intact handshake loop in the diagram is  156 ,  152 ,  154 ,  156  . . . . The broken handshake loop is  156 ,  158 ,  156 ,  158  . . . . 
     Many other approaches possible handshaking protocols and apparatus will be obvious to those skilled in the art. 
     Finally (see hereinbelow), downloading a treatment plan or routine for a currently happening ME-IMD session, for storage in the IMD memory, may allow for the completion of a ME set of treatment steps which were interrupted by a break in communications. 
     Many implanted devices have a low battery drain and a longevity measured in years. If the same battery that supplies a minimal amount of energy for device function (e.g. cardiac pacing, where the current drain may be 10-20 microamps or less) must also supply a transmitter, then unless there is judicious power management, there may be substantial shortening of device battery life. Among the options for accomplishing this are: 
     a) programming notification criteria so that the function is not over-used; 
     b) the placement of one or more relay units (see below) in proximity to the IMD/patient, so that transmission from the first T/R involves only short distances; 
     c) methods of powering down the first T/R, partially, during a transmission, if possible; 
     d) monitoring battery function so that as the battery ages, the criteria for notification may be made more restrictive; 
     e) letting the ME know the battery status during a transmission, so that the ME, recognizing an aging battery or batteries, may take action to shorten the current transmission and limit future ones, perhaps by either (i) remotely reprogramming notification criteria, or (ii) remotely programming transmitter power consumption; 
     f) having a dual power supply arrangement, where one power supply powers only the device T/R (or only the device transmitter), and one power supply powers everything else in the device. An alternate embodiment of this approach would be to the transmitter (or T/R) battery or batteries to be rechargeable. 
     Four exemplary ways of handling battery management are illustrated by the embodiments of the invention shown in  FIGS. 4A-4D . Hereinbelow, the word battery may refer to a single cell, two or more cells in series, two or more cells in parallel, and may refer to combinations of these.  FIG. 4A  contains a single battery  200  which supplies each of the components of the IMD. In addition to supplying the components discussed hereinabove in conjunction with  FIG. 1 , the battery also supplies battery monitoring apparatus  202  with energy.  202  monitors one or more of battery voltage, cell impedance, battery current drain, the droop in cell voltage with increased demand, and indirect measures of battery function (e.g. the charge time of an ICD). The battery information is supplied to the IMD transmitter  206 , for transmission to remote station  208 , for assessment by the ME. The ME may use the information for management of real-time power consumption (i.e. reduce transmitter power during the current encounter) by sending a signal to receiver  210 , which passes the information contained therein to transmitter  206 . Alternatively, the MP may reprogram device performance (e.g. notification criteria), by sending a programming command from  208  to  210  to the logic device (which coupling is not shown in  FIG. 4A , but is indicated in  FIG. 1 . 
       FIG. 4B  shows a one battery management approach where management is directed within the IMD, i.e. by the IMD logic device. Information  236  about battery  240  (similar to the information discussed hereinabove in conjunction with  FIG. 4A ) is processed by logic device  220 , and may be used maximize the longevity of the battery, as discussed hereinabove. Besides power reduction signals  234  which reduce transmitter  230  power by a variety of possible values, a signal  232  may be sent to power  230  off. As indicated,  220  may also reprogram itself to accomplish such goals as altered notification criterion. 
     It is possible to combine the attributes of the power conservation approach shown in each of  FIGS. 4A and 4B . 
       FIG. 4C  shows a dual power supply approach to power management. As shown in the figure, battery  252  powers the device components except for the device T/R  253  (and perhaps the battery monitoring apparatus  254 ), which are powered by battery  250 . Battery information moves from  254  to transmitter  256  to remote station  258  for evaluation by the ME. The ME may control transmitter characteristics by sending a signal from  258  to receiver  260  to transmitter  256 . In addition, the presence of a second battery gives the ME some additional options: the use of one of the batteries to perform the function of the other. Thus if battery  252 , which controls the IMD in general, is nearing its end of service, and transmitter battery  250  has a substantial remaining energy supply, the ME may cause switching apparatus  262  to divert some or all of  250  energy to perform the functions intended for battery  252  (i.e. non-transmitter function). Similarly, the MP may do the mirror image diversion: In a situation with good  252  energy supply, poor  250  energy supply and the need for an urgent interaction with a ME, switching apparatus  264  may divert energy to transmitter  256  that might otherwise not have been able to be supplied by  250 . The ME could learn about the status of battery  252  by information passed along the link from it to  254 , and thence to  256  and  258 . 
       FIG. 4D  shows a 2 battery configuration, with energy management by the IMD logic device. All of the functions performed by the apparatus in  FIG. 4C  could be performed by that in  FIG. 4D , except that the source of management commands is logic device  270 .  270  processes information  274  about the status and projected longevity of  272 , and may use it to either (i) make one or more reductions  278  in the power consumption of  280 , or (ii) turn off  276  the transmitter. 
     A wide variety of possible triggers for ME notification are possible.  FIGS. 5A and 5B  illustrate a situation in which a single parameter (e.g. heart rate) is monitored to determine device action. Conventional ICDs (which include pacemaker function) are programmed to treat tachycardias which are above a certain heart rate, and bradyarrhythmias whose rate is below a certain heart rate. The scenario illustrated by  FIG. 5A  shows a scenario in which a range of rates which is intermediate between the high rate, at which treatment is definitely required, and the normal rate, may be defined as the notification range of rates. For example, an ICD might be programmed to: 
     a) notify for rates from 140 to 160 bpm and to treat and notify for rates above 160 bpm. The ME, upon notification, would decide whether treatment is required for a rate of say, 150 bpm, and if so, cause the ICD to provide such treatment. The ME might decide (a) to try some gentle treatment such as a non-aggressive anti-tachycardia pacing for the situation, (b) to go ahead and provide aggressive treatment, or (c) to not treat at all. In the latter case, the ME might decide to check the patient at some later time, e.g. by leaving an instruction in the ICD for the ICD to check in with the ME in 30 minutes. The ME might further program altered “second notification” criteria, i.e. if the rhythm normalizes, then over the next 24 hours, the threshold for notification is lower (e.g. 130 bpm). 
     b) notify for rates from 140 to 160 bpm and to treat (and not notify) for rates above 160 bpm. [This is not shown in the figure.] This saves battery in cases where there is little or no uncertainty about which therapy is the appropriate one. 
     In the figure, a similar format is programmed for bradyarrhythmia. For example, the pacing circuits may treat when the rate declines to 40 bpm, but may be programmed to notify for rates in the range of 40 to 50 bpm. Alternatively, the programming person might choose not to notify for pacing at 40 bpm (i.e. treat without notification). 
       FIG. 5B  shows a format in which the ME is notified (and treatment is given) for values of a parameter that are extreme but not for values that are only moderately abnormal. For example, the ME might be notified for tachycardia that was treated whose rate was 260 bpm, but not for tachycardia which were treated with rate less than 200 bpm. 
     The aforementioned scenarios reflected by  FIGS. 5A and 5B  concern rather simply notification criteria. More complex ones may depend on the results of multiple different parameters from multiple sensors, and their evolution over time. Still more complex scenarios may depend not just on the measured values of these parameters, but complex mathematical functions of them. 
     Once notification has occurred, the other dimension of interaction between the IMD and the ME, is how much control the ME has access to, following notification.  FIG. 6A  shows a scenario in which the ME is given essentially complete control. The right hand side of the figure shows the essential features of operation when the device operates autonomously. Following detection of a parameter value  302  which requires therapy, the device applies the pre-programmed therapy  308 , and optionally transmits a confirmation signal, block  310 , indicating that therapy has been provided. However, if notification criteria have been met,  312 , the IMD sends a notification signal,  314 , for receipt by a remote station, and awaits a response,  316 . Once the ME is in communication with the IMD, the ME may both positively and negatively control the device; That is, the MEP may choose to inhibit (block  318  to  306 ) an action that the device, if operating autonomously, would have performed. Alternatively the ME may choose to cause the device to deliver therapy, even though the IMD program may not have called for this. In such a circumstance, block  318  leads to  320 , in which an ME command is decrypted and decoded, and then to  322 , in which the therapy instructions are carried out, followed by the sending of confirmation signal  324 . 
     Since the establishment of a communication link between the ME and the IMD may take a short time, an optional delay  304  is added in before the IMD acts autonomously, in a situation when notification has occurred. This is indicated by block  312  inducing optional delay  304 , to prevent autonomous IMD therapy before the ME can be involved. 
     The ME has a number of options for influencing the management of future events post notification, shown in block  326 . In a preferred embodiment of the invention, the ME may reprogram (a) notification criteria, (b) the definition of what constitutes and abnormality, in terms of autonomous device functioning, (c) aspects of sensor signal analysis, (d) the details of therapy during autonomous device functioning, (e) communication management [route, mode, channel, etc.], (f) battery management, (f) followup management (the ability of the ME to ask for a callback from the IMD) after a ME-managed-event, to report patient status), and (g) communication termination management (e.g. how long until communication ends after [i] a successfully managed event, and [ii] an event in which communication failed during the event). 
       FIG. 6B  shows another management scenario. Two operating modes are defined for the IMD. In a first operating mode (O.M.=1, in the figure) the IMD logic device is in control of therapy, while in a second operating mode (O.M.=2, in the figure), the ME is in control. The scenario shown in  6 A involved moment to moment choices by the ME of whether to inhibit an IMD function; In the scenario in  6 B, all IMD function is inhibited in the second operating mode, unless (a) the ME chooses to return the control to the IMD (block  350  to  352  via broken line indicating optional feature), or (b) communication fails [ 350  to  352  via solid arrow]. In other aspects not explicitly mentioned, the algorithm in  FIG. 6B  is identical to that of  6 A. 
       FIG. 6C  shows a different algorithm. In this case, the decision between remote and local management is made (a) early on [i.e. before the ME is involved], and is made by the logic device of the IMD. Other aspects of the figure not specifically discussed are similar to those in already discussed figures. 
       FIG. 6D  shows another algorithm in which the remote station (RS) is given a particularly high level of priority. If an abnormality is detected by the IMD which may require treatment  360 , signals are transmitted to the ME  362 , at which point, two determinations are made: (a) Is therapy warranted [block  364 ]? and (b) Is the source of therapy-related choices to be local (i.e. the IMD) or remote (i.e. the ME)[block  366 ]?If the source of therapy is to be local, the ME returns control to the IMD. Other aspects of the figure not specifically discussed are similar to those in already discussed figures. 
     Other scenarios in which the ME does not have top priority have been discussed hereinabove. 
     Since battery conservation is a major concern with IMDs, and since wireless communication is a feature, the most efficient way to manage such devices is to provide one or more relay units between the IMD and the ME. Having one such unit in close proximity to the IMD will help to limit IMD battery depletion. Many possible relay units may be designed, and are known in the art. The essential features of such a unit are shown in  FIG. 7 . A fourth transmitting and receiving device, “fourth T/R”  370  communicates wirelessly with the first T/R  372  of the IMD  374 .  370  is linked within relay unit  376  to a third T/R  378 . The communication of the third T/R with the remote station  382  is via the second T/R  380 . The communication between  378  and  380  may be wired (broken line) or wireless. It may involve no intervening communication device, or a number of such devices. It may involve a public telephone carrier or a private network, and may involve the Internet. 
       376  contains telecommunications control unit  384 , which may adjust the operating characteristics of the third T/R to optimize communication with the remote station, and adjust the operating characteristics of the fourth T/R to optimize communication with the IMD. An optional second input device  386  could allow a local person or the patient to have some or complete control of the IMD; An optional third input device  388  could allow a local person or the patient to send a signal (e.g. a notification signal) to the ME. This could be used in a case where the patient feels that observation and potential ME intervention is warranted. 
     The following description details a preferred embodiment of the invention, entailing an ICD as the IMD. “MP” refers to a medical professional, which is the human version of the aforementioned ME. 
     Hereinabove and hereinbelow, ICD is intended to include: 
     A) devices which can administer a defibrillation shock; and 
     B) devices which can administer a defibrillation shock and can administer cardiac pacing. It is to be understood that this technology may be used in any implantable medical device, and any remotely controlled critical system. 
     Features of the Invention 
     1) The Implantable Cardioverter Defibrillator (“ICD”) may initiate the communication between itself and the Central Station (“CS.”) Mechanisms for this are illustrated. 
     2) The “control unit” referred to in Ser. No. 10/460,458 may be: 
     A) a cellular telephone or other personal communication devices (such as a Blackberry®) as are known in the art. 
     B) the Stationary Unit referred to in Ser. No. 10/460,458; and 
     C) any relay unit whose purpose is to amplify the signal as it is passed along between ICD to CS. 
     Hereinbelow, the unit which serves as the communications hardware link between the CS and the ICD shall be referred to as the repeater unit (“RU”). 
     3) Means within the ICD may select alternate mode of communication (e.g. a public or private telephone network, or the internet) and may select alternate routes of communication (e.g. in a multi-segment communication, selecting each segment of the total communications link.
 
4) Handshake signals may be exchanged between:
 
     A) the CS and the RU; 
     B) the RU and the ICD; and 
     C) the CS and the ICD. 
     The handshake signals may be used to indicate the presence or absence of communication signals between two components (e.g. the ICD and the RU) or to indicate the quality of the signals. 
     5) If the handshake signals indicate either an absent communications link or a poor quality one, the handshake signals may be used to cause the ICD to: 
     A) select an alternate mode of communications; 
     B) select an alternate route of communications; 
     C) increase the power output of the ICD transmitter; 
     D) increase the sensitivity of the ICD receiver. 
     6) The communications route from the ICD to the CS may involve multiple segments. These segments may include: 
     A) an ICD to RU segment; 
     B) one or more RU to RU segments; 
     C) a RU to CS segment; and/or 
     D) a direct ICD to CS segment. 
     7) Ser. No. 10/460,458 presents two formats for ICD control by a remotely located medical professional (“MP”): 
     Format A) In one (claim  219  and the 24 dependent claims which follow), the MP has primary control, and, in the absence of proper communication between the ICD and the MP, the ICD is in control; 
     Format B) In the other (claim  244  and the 25 dependent claims which follow), the ICD has primary control. The MP may overrule the ICD on a therapy decision, if he deems this to be desirable. 
     Feature 7 presents an approach in which the choice between Format A and Format B may be: 
     A) “hardwired” into the ICD; 
     B) irreversibly programmable (using a PROM, EPROM, EEPROM, etc., as is known in the art) 
     C) programmable by the medical professional who is responsible for programming the patient&#39;s ICD an a routine basis; 
     D) programmable by the MP, at the time of a medical emergency which has caused the ICD to communicate with the MP; and/or 
     E) programmable by the ICD, at the time of a medical emergency which has caused the ICD to communicate with the MP. 
     8) When the ICD initiates a communication with the CS, there may be a 2-or-more tier format such that: 
     A) 2 or more levels of emergency are defined; 
     B) for each level, a greater degree of “communications aggressiveness” (on the part of the ICD) is defined. 
     For example: 
     2 levels of emergency:
         Moderate emergencies include ventricular tachycardia (“VT”) at rates less than 160;   Major emergencies include a) VTs at rates greater than or equal to  160  and b) VTs or ventricular fibrillation (“VF”) requiring a shock.       

     The corresponding two levels of communication aggressiveness would be:
         For Moderate emergencies: a) no ICD transmitter output power boost (see below); and b) a small number of repeat attempts by the ICD to contact the CS; and   For Major Emergencies: a) one or more ICD transmitter output power boosts; and b) a large number of repeat attempts by the ICD to contact the CS.
 
Examples with 3 or more levels are obvious.
 
There is also the possibility of moderate emergencies (or the lowest level of emergency in a three or more level setup) resulting in no attempt at communication by the ICD.
 
9) Referring to 8) above, the definition of each level of emergency may be:
       

     A) “hardwired” into the ICD; 
     B) irreversibly programmable (using a PROM, EPROM, EEPROM, etc., as is known in the art) 
     C) programmable by the medical professional who is responsible for programming the patient&#39;s ICD an a routine basis; 
     D) programmable by the MP (after communication between the MP and the ICD has been established), at the time of a medical emergency which has caused the ICD to communicate with the MP; and/or 
     E) programmable by the ICD (after the event which calls for a communication between MP and ICD); and/or 
     F) programmable by the ICD (during the event which calls for a communication between MP and ICD), if ICD circuitry determines that battery conservation requirements dictate a shut-down of the communication link. 
     10) Options based on battery reserve of ICD: 
     If hardware/software within the ICD determines that the ICD battery reserve is low, ICD options include: 
     A) terminate the communication; 
     B) send a message to the MP indicating the low reserve, and then terminate the communication; 
     C) lower power output and attempt to continue the communication; (This step may be repeated one or more times.); and/or 
     D) continue the communication with output as is, and repeat assessment at a future time. 
     11) End of communication options: 
     The communication may end: 
     A) because of low ICD battery reserve, see Feature 10), above; 
     B) because the MP determines that further communication is not warranted; and/or 
     C) because the ICD logic unit determines that further communication is not warranted. 
     12) Identification-related issues: 
     Privacy in the communication between the ICD and the MP to be maintained: 
     A) Encryption and decryption per means and methods:
         i) in Ser. No. 10/460,458; and   ii) others, known in the art;       

     B) An identification system wherein any ICD requires proof of MP identification, before and during and communication session. 
     13) The download of contingency plans from MP to the ICD, as soon as possible after the exchange of information begins. The purpose of the contingency plan download is to have a management strategy in place within the ICD, should the ICD-MP communication get interrupted midway through the event. Although the basic system calls for the ICD to revert to its programmed behavior in the event of communications interruption, the MP may desire to leave a temporary plan in place, to be used for the remainder of the current medical event. The MP may update the contingency plan as needed, as the medical event progresses. 
     An example of such a contingency plan would be more aggressive (or less aggressive anti-tachycardia pacing, prior to defibrillator shock). Another example would be to eliminate all intermediate energy shocks, and deliver only high energy shocks. Numerous other examples will be apparent to those skilled in the art. 
     Referring to the figures, which show additional documentation of the means and methods of accomplishing the above 13 features: 
       FIG. 8  shows a patient  400  with and ICD  402  which communicates with a MP  404  at a MP communication station  406 .  406  may be a central station as described in Ser. No. 10/460,458 or a central or peripheral station as described in Ser. No. 11/502,484. The ICD antenna is not shown, but in  FIGS. 8-10 , it is to be understood that the ICD has one or more antenna which allows it to properly communicate. 
     The communication route is in either direction between: 
     A) the T/R device within the ICD; 
     B) the T/R device within personal communication device  410 ; and 
     C) the T/R device within the MP communication station. 
     The communication route may also be directly between the T/R device within the MP communication station and the T/R device within the ICD. 
     Referring to  FIG. 9 : It is also possible to have two or more intermediate communication links between the ICD T/R and the T/R of the MP communication station. In  FIG. 9 , there are two personal communication devices  1200  and  1202  and a repeater unit  1204  (as discussed above). Possible arrangements include: 
     A) two or more personal communication devices and no repeater units; 
     B) one or more repeater units and no personal communication devices; and 
     C) one or more repeater units and one or more personal communication devices. 
     It is also possible that the communications route would change during a single medical event. This could occur if either the MP or the hardware/software within the ICD determines that a change of route is desirable. 
     The antennae shown for  406  may, at times, not be used, since at times, communication with  406  may be via “land line.” 
       FIG. 10  shows that each segment of the communication route may be: 
     A) via satellite(s) ( 1300 ,  1302  and  1304  in the figure, each of which may represent a single satellite or an array of multiple ones); 
     B) via a non-line-of-sight radiofrequency link ( 1310 ,  1312 ,  1314 ); 
     C) via a line-of-sight radiofrequency link ( 1316 ,  1318 ,  1320 ); 
     D) via a public or private telephone network; 
     E) via cell-phone and/or personal communication device network ( 1322 ,  1324 ); 
     F) in the links beyond the ICD link, via “land lines  1308 ;” and/or 
     G) combinations of A-F 
     The PCD  1326  in figure PCD in  FIG. 10  may be replaced by a wireless router such that the communication between the ICD and the MP is ICD  1328 ←→wireless router←→internet ←→MP communication station  1330 . The route from the wireless router to the communication station can have a wide variety of configurations, as is known to those skilled in the art. 
       FIG. 11  shows one possible algorithm for allowing the ICD to communicate with a MP communication station, with or without an intervening repeater unit/cell phone/stationary unit/control unit. 
     If/when the ICD detects an abnormal heart rhythm that requires action, may require action or requires analysis, block  1400 , it determines whether the rhythm requires communication with the MP. One method of determination is to classify rhythm abnormalities as either major or not major, and to communicate if the rhythm abnormality is major. This determination is made at block  1402 . 
     The figure shows a setup with two levels of emergency, as described in Feature 8, hereinabove. If the rhythm is determined, block  1402 , not to be a major emergency, but is a moderate emergency, block  1404 , then continued monitoring, bock  1406 , is in order, to monitor for the possibility of the event turning into a major emergency; If this occurs, return to block  1402 , and proceed with major emergency section of the algorithm. If there is neither a major nor a moderate emergency, block (either because the emergency condition has resolved, or because there is an abnormality which is less urgent than even the moderate category), the algorithm shown in  FIG. 11  ends. ICD monitoring, of course, continues as always. 
     If a major emergency is detected, block  1410 , the ICD T/R is turned on. Not leaving it on continuously saves the battery charge. The ICD then attempts to contact the MP, block  1412 . A handshake protocol, which may have some or all elements of that described in Ser. No. 10/460,458 or may have one or more features of other handshaking protocols as are known in the art, ensues, block  1414 . 
     If the handshake is unsuccessful, or (optionally) if the quality of the handshake is sub-optimal, block  1416  lists six possible options. These include:
         1) repeat attempt at handshake, using the same communication parameters;   2) change communication mode (as defined in Ser. No. 10/460,458) and repeat handshake attempt;   3) change communication route (as defined in Ser. No. 10/460,458) and repeat handshake attempt;   4) increase ICD transmitter power and repeat handshake attempt;   5) wait, and then repeat the handshake attempt, either with the same transmitter/mode/route parameters or one of more altered ones; and/or   6) suspend efforts to contact the MP.       

     In the case of the options 1-5, block  1416  leads to block  1412 : a repeat attempt to contact the MP. 
     In the case of option 6, block  1416  leads to  1408  and the algorithm ends. Option 6 may be selected after a pre-programmed number of attempts to reach the MP has occurred. Alternatively, the number of attempts may not be pre-programmed and may depend on the ICD battery status (see hereinbelow), or the level of the emergency. 
     If the handshake is successful, than the MP will have the opportunity to participate in the management of the emergency. The format for such participation is:
         a) pre-programmed Format A (MP control is primary; ICD control is in the event of communications interruption);   b) pre-programmed Format B (ICD control is primary; MP control in the event that the MP chooses to override the ICD decision);   c) either Format A or Format B, with the choice made by the MP at the time of the event; or   d) either Format A or Format B, with the choice made by the ICD based on the severity of the event.       

     As indicated hereinabove, the aforementioned Format selection is made, block  1418 , leading to either Format A/block  1420 , or Format B/block  1422 . Thereafter the MP either manages, co-manages (with the ICD) or observes the emergency event, block  1424 . 
     The communication between the ICD and the MP may terminate in one of three ways: 
     A) by necessity, because the ICD battery has reached a point in its discharge, where it is deemed unwise to continue communications; 
     B) due to the heart rhythm-related emergency having been resolved; or 
     C) due to an unintended interruption of communications. 
     In the event of A), block  1424  leads to  1426 , which leads to a MP notification, block  1428 . This may be followed by:
         1) The ICD immediately turning off its T/R, block  1430 ;   2) The MP deciding to immediately turn off the ICD T/R, block  1430 , or,   3) block  1424 , the MP deciding to take some additional time to communicate, despite the low battery warning.       

     Algorithms which omit the warning to the MP of impending ICD T/R shutoff are possible. 
     In the event of B), block  1424  leads to  1426 , which leads to  1432 , which leads to  1430 . 
     In the event of C), attempts to re-establish communication occur, as described in Ser. No. 10/460,458. During the time when communication has not been established, the ICD logic unit manages the case. 
     To avoid a situation where the ICD logic unit must takeover in the middle of an event which the MP was managing in a different manner than would have been executed by the logic unit, the MP may, from time to time download contingency plans to the ICD, block  1434 , such that, in the event of an interruption, the ICD has enough of the current MP decision making algorithm to complete the management of the event. This approach is discussed hereinabove, as Feature 13.