Abstract: A pacing system delivers cardiac protection pacing to protect the heart from injuries associated with ischemic events. The pacing system detects an ischemic event and, in response, initiates one or more cardiac protection pacing sequences each including alternative pacing and non-pacing periods. In one embodiment, the pacing system initiates a cardiac protection pacing sequence in response to the detection of the onset of an ischemic event, such that a pacing concurrent conditioning therapy is applied during the detected ischemic event.

Abstract: The present invention relates in general to methodologies for the treatment quenching preconditioning and communication between the peripheral cardiac nervous system and an electrical stimulus. In particular, the present invention utilizes spinal cord stimulation to alter and/or affect the peripheral cardiac nervous system and thereby protect cardiac function.

Abstract: Tachyarrhythmia is treated by applying anti-tachycardia pacing through at least one multi-site electrode set located on, in or around the heart. The electrode set is arranged and located such that an electrical activation pattern having a wave-front between substantially flat and concave is generated through a reentrant circuit associated with the tachyarrhythmia. The electrode set may be one of a plurality of predefined, multi-site electrode sets located on, in or around the atria.

Abstract: Methods and systems for classifying cardiac responses to pacing stimulation and/or preventing retrograde cardiac conduction are described. Following delivery of a pacing pulse to an atrium of the patient's heart during a cardiac cycle, the system senses in the atrium for a retrograde P-wave. The system classifies the atrial response to the pacing pulse based on detection of the retrograde P-wave. The system may also sense for an atrial evoked response and utilize the atrial evoked response in classifying the cardiac pacing response.

Abstract: A cardiac contractility modulating (CCM) device (30) includes an anti-arrhythmic therapy unit (38) for detecting a cardiac arrhythmia in a heart (2) of a patient based on processing electrical signals related to cardiac activity sensed at the heart, and for delivering anti-arrhythmic therapy to the heart. The device includes a cardiac contractility modulating (CCM) unit (40) capable of delivering cardiac contractility modulating (CCM) signals to the heart for modulating the contractility of a portion of the heart. The device (30) includes a power source (165). The device may be an implantable device or a non-implantable device. A method for delivering anti-arrhythmic therapy to a heart. The method includes applying one or more non-excitatory cardiac contractility modulating electrical signals to said heart.

Abstract: In some embodiments, a method for operating a cardiac rhythm management device may include one or more of the following steps: (a) sensing atrial depolarizations through an implanted atrial electrode, (b) administering a sequential CRT pacing therapy in a sequential CRT pacing mode to a left and right ventricle of a heart of a patient via implanted ventricular electrodes in a sequential bi-ventricular fashion, (c) switching from the sequential CRT pacing mode to a simultaneous CRT pacing mode, (d) administering a simultaneous CRT pacing therapy in the simultaneous CRT pacing mode to the left and right ventricle in a simultaneous bi-ventricular fashion, (e) analyzing the sensed atrial depolarizations to detect the presence of an atrial arrhythmia, (f) analyzing the sensed atrial depolarizations while in the sequential CRT pacing mode to detect the presence of atrial arrhythmia, and (g) sensing ventricular depolarizations of the left and the right ventricle.

Abstract: Methods and systems for identifying tachyarrhythmia episode types and delivering therapy to mitigate the identified tachyarrhythmia episode types are described. Electrogram signals of cardiac activity are sensed and stored by an implantable cardiac device. Tachyarrhythmia episodes are detected and tachyarrhythmia episode types are identified based on characteristics of the electrogram signals. In preparation for performing ablation, a tachyarrhythmia episode is induced. The features of the induced tachyarrhythmia episode are compared to characteristics of the identified episode types. A similarity between the induced tachyarrhythmia episode and at least one of the episode types identified from the stored electrogram signals is indicated to facilitate performing the ablation.

Abstract: In general, the disclosure describes techniques for predicting the occurrence of an arrhythmia based on an indication of heart rate turbulence. An example method comprises sensing a parameter indicative of heart rate turbulence, measuring heart rate turbulence based on the sensed parameter, and predicting an occurrence of an arrhythmia based on the measured heart rate turbulence.

Abstract: Techniques are described for discriminating ventricular tachycardia (VT) from supraventricular tachycardia (SVT) using an implantable medical device capable of multi-site ventricular sensing. In one example, ventricular depolarization events are detected within a patient by the implantable device during a tachyarrhythmia, at both a left ventricular sensing site and a right ventricular sensing site. Ventricular event timing differences are then ascertained. The device compares the ventricular event timing differences detected during the tachyarrhythmia with predetermined supraventricular event timing differences for the patient, such as event timing differences previously detected within the patient during sinus rhythm or extrapolated from sinus rhythm values. The device then distinguishes VT from SVT based on the comparison of the event timing differences detected during the tachyarrhythmia with the predetermined supraventricular event timing differences.

Abstract: Techniques for determining whether a lead related condition exists based on analysis of a cardiac electrical signal associated with a non-sustained tachyarrhythmia (NST) are described. In some examples, the techniques include determining the duration of intervals between consecutive cardiac events, e.g., R-R intervals, during an NST. The techniques may further include determining one or more metrics based on the durations of the intervals during the NST. Examples of metrics include an average, a minimum, a maximum, a range, a median, a mode, or a mean. A lead related condition is identified based on the values of the one or more metrics, e.g., by comparison to respective thresholds. In some examples, an alert is provided or a therapy modification is suggested if a lead related condition is identified.

Abstract: A cardiac rhythm management (CRM) system includes an implantable medical device that delivers anti-tachyarrhythmia therapies including ATP. When a tachyarrhythmia episode is detected, the implantable medical device analyzes the morphology of a cardiac signal to determine whether and/or when to deliver an ATP therapy. In various embodiments, the implantable medical device produces morphological parameters indicative of the likeliness of success of the ATP therapy and selects an anti-tachyarrhythmia therapy mode based on the morphological parameters. In various embodiments, the implantable medical device also controls the timing of the ATP therapy delivery using morphological features of the cardiac signal to maximize the probability that the ATP therapy is delivered into an ATP window during which a tachyarrhythmia episode can be effectively terminated by pacing.

Abstract: To shorten the length of a lead, alleviate physical burden on a patient in installation of a device into a body, and miniaturize the device while allowing both treatment based on cardiac stimulation and nerve stimulation.

Abstract: A method and system are provided for trending variation in coronary burden across multiple heart rate ranges. The method and system include obtaining cardiac signals having a segment of interest over a period of time where each cardiac signal has an associated heart rate that falls within at least one heart rate range. Segment variations of the segment of interest are determined and grouped based on the associated heart rates to produce distributions of segment variations that are associated with the heart rate ranges. Trending information is produced by automatically comparing the distributions of segment variations between different heart rate ranges.

Abstract: A method for operating a cardiac pacemaker in which the mode of operation of the pacemaker is altered in response to detecting an episode of atrial tachycardia. In accordance with the invention, the pacemaker's pacing mode is altered in a manner that attempts to maintain hemodynamic stability during the atrial tachycardia. Such a mode switch is particularly applicable to pacemaker patients suffering from some degree of congestive heart failure.

Abstract: An apparatus comprises an implantable sensor, a stimulation circuit, and a controller. The implantable sensor is configured to provide a sensor signal representative of hemodynamic function of a subject. The stimulation circuit is configured to provide electrical simulation energy to an implantable electrode. The controller is communicatively coupled to the stimulation circuit and the implantable sensor and includes a hemodynamic monitor module. The hemodynamic monitor module is configured to detect an episode of reduced hemodynamic capacity in a subject using the sensor signal. In response to the detected episode, the controller is configured to initiate delivery of the electrical stimulation energy to artificially induce at least one of deep ventilation or rapid ventilation in the subject. The hemodynamic monitor module is configured to obtain a measure of hemodynamic performance after delivery of the electrical stimulation energy.

Abstract: A cardiac medical device and associated method control delivery of dual chamber burst pacing pulses in response to detecting tachycardia. In one embodiment, a single chamber pacing pulse is delivered in response to detecting a tachycardia. Dual chamber pacing pulses are delivered subsequent to the single chamber pacing pulse. An intrinsic depolarization is sensed subsequent to delivering the dual chamber pacing pulses. The tachycardia episode is classified in response to the sensed intrinsic depolarization.

Abstract: A cardiac medical device and associated method control delivery of dual chamber burst pacing pulses in response to detecting tachycardia. A number of cardiac cycles occurring in a first cardiac chamber are identified subsequent to the dual chamber pacing pulses. The number of sensed intrinsic events occurring in a second cardiac chamber during the first chamber cardiac cycles is determined as a number of second chamber events. The tachycardia episode is classified in response to the number of second chamber events.

Abstract: Tachyarrhythmia is treated by applying anti-tachycardia pacing through at least one multi-site electrode set located on, in or around the heart. The electrode set is arranged and located such that an electrical activation pattern having a wave-front between substantially flat and concave is generated through a reentrant circuit associated with the tachyarrhythmia. The electrode set may be one of a plurality of predefined, multi-site electrode sets located on, in or around the atria. Alternatively, the electrode set may be formed using at least two selectable electrodes located on, in or around the atria.

Abstract: A tachyarrhythmia detection and classification system classifies tachyarrhythmias based on an analysis of morphological features of a cardiac signal enhanced by using one or more physiological parameters indicative of hemodynamic stability and/or activity level. The tachyarrhythmia detection and classification system computes a measure of similarity between an arrhythmic waveform of the cardiac signal, a template waveform for that cardiac signal, such as a correlation coefficient representative of the correlation between morphological features of the arrhythmic waveform and morphological features of the template waveform. A detected tachyarrhythmia episode is classified by comparing the measure of similarity to a threshold that is dynamically adjusted using the one or more physiological parameters.

Abstract: The present invention relates in general to methodologies for the treatment quenching preconditioning and communication between the intrinsic cardiac nervous system and an electrical stimulus. In particular, the present invention utilizes spinal cord stimulation to alter and/or affect the intrinsic cardiac nervous system and thereby protect the myocytes, stabilize myocardial electrical instability and/or alleviate or diminish cardiac pathologies.

Abstract: A method of delivering electrical therapy to a patient by a medical device includes activating the medical device and performing a first analysis of a first set of data signals sensed by the medical device. If the first analysis shows the first set of data signals meets a first criterion, then charging of an energy delivery circuit is commenced upon completion of the first analysis. A second analysis of a second set of data signals from the patient is performed, and if the second analysis determines that the second set of data signals meet a second criterion, the therapy is delivered. The steps of performing the first analysis and performing the second analysis may be begun at substantially the same time. The step of charging may overlap in time with the step of performing a second analysis. The medical device may be an external defibrillator and the therapy may be a defibrillating shock.

Abstract: In general, this disclosure provides techniques for heart monitoring. In accordance with the techniques described in this disclosure, an implantable medical device (IMD) may assess cardiac wall motion using impedance measurements through cardiac leads. As an example, the IMD may calculate an amount or rate of change in impedance due to the motion of a wall of the heart during at least a portion of one cardiac cycle, e.g., systole, in order to assess the strength of systolic contraction.

Abstract: A pacing monitoring system is described for incorporation in an implantable pacemaker that monitors the pacing rate and/or cumulative pace count in order to protect a patient from excessive pacing. The system includes monitoring circuitry that is configured to operate in multiple monitoring zones, where each zone is adapted to prevent excessively high-rate pacing during a particular mode of device operation.

Abstract: An implantable device for terminating ventricular tachycardia is disclosed. The device includes a processor configured to determine a first antitachycardia pulse routine of N pulses. In the routine the first N?1 pulses are separated by a first cycle length and the Nth pulse is separated by a second cycle length that is shorter than the first cycle length. The device also comprises a lead coupled to the processor. The lead comprises an electrode configured to sense a tachycardia and further configured, under control of the processor, to administer the antitachycardia pulse routine.

Abstract: A cardiac rhythm management system can be used to detect episode beats associated with cardiac events in a subject's body. These events may be monitored and depolarization morphology information can be derived for candidate arrhythmic beats in an arrhythmia episode. An arrhythmic beat morphology template may be formed from selecting at least one of the candidate arrhythmic beats based upon user's labeling according to specific morphologies of one or more candidate episodes. Methods of use are also presented.

Abstract: An active implantable medical device of the AAI/DDD type, notably a cardiac pacemaker, including automatic mode adjustment at implantation. The device detects spontaneous atrial and ventricular events, and is able to pace the atrium and ventricle. The device can operate in an AAI mode with ventricular sensing, a DDD mode, and includes automatic mode commutation, able to schedule, as a function of predetermined criteria, commutation from AAI to DDD mode, and reversely from DDD to AAI. The device automatically detects an implantation and has its initial mode of operation adjusted upon detection of the implantation (10). The device temporarily operates (14) in an AAI mode with activation of the means for mode commutation, then analyzes (20) the atrio-ventricular conduction so as to detect whether a potential conduction disorder exists. In case of a potential conduction disorder existing (presence) (24), the device is then set to a DDD mode and the automatic mode commutation is inhibited.

Abstract: Apparatus (20) for treating a subject (30) suffering from spontaneous atrial fibrillation includes an electrode device (22), adapted to be coupled to a site of the subject (30) selected from the list consisting of: a vagus nerve (24) of the subject (30), an epicardial fat pad of the subject (30), a pulmonary vein of the subject (30), a carotid artery of the subject (30), a carotid sinus of the subject (30), a vena cava vein of the subject (30), and an internal jugular vein of the subject (30), and a control unit (32), adapted to drive the electrode device (22) to apply an electrical current to the site, and to configure the current to maintain the spontaneous AF for at least about 24 hours, so as to modify blood flow within the atria and reduce risk of thromboembolic events.

Abstract: A cardiac rhythm management device is configured to detect oscillations in cardiac rhythm by comparing electrogram signals during successive heart beats. Upon detection of electrical alternans, the device may adjust its operating behavior to compensate for the deleterious effects of the condition.

Abstract: Precursor of fatal arrhythmia is detected and by setting the tolerance level for carrying out nerve stimulation depending on the severity degree of the precursor, significant variation of the heart rate is suppressed and induction of the fatal arrhythmia is repressed. For this purpose, precursor of tachyarrhythmia occurrence such as premature contraction, ST change, repolarization abnormality or the like is detected and the lower-limit of the atrium interval which becomes the tolerance level of the nerve stimulation is set according to the detected result. Then, it is constituted according to the precursor of aforesaid tachyarrhythmia such that time for making the nerve stimulation means in an operation state is to be adjusted or nerve stimulation is to be carried out as much as the heart rate of a predetermined number of times.

Abstract: The present application discloses a complexity-based method for synthetically detecting ventricular fibrillation, which centers on complexity calculations while incorporating a plurality of feature values and thus differentiates more effectively among various types of ECG signals. The method further modifies the complexity algorithm, making it more adapted to reflecting characteristics of the VF-related signals, thereby enabling high sensitivity and specificity of detection. Further, the related calculation load is reduced according to the algorithm. As such, the method can fully satisfy the clinical needs and is aimed for solving the problems of low sensitivity, low specificity and weak anti-interference ability present in current medical equipment for detecting ventricular fibrillation, such as monitors, implanted cardioversion defibrillator (ICD), automatic external defibrillator (AED) and so on. Systems for performing the method are also disclosed.

Abstract: Techniques are provided for use by implantable medical devices for controlling ventricular pacing, particularly during atrial fibrillation. In one example, during a V sense test for use in optimizing ventricular pacing, the implantable device determines relative degrees of variation within antecedent and succedent intervals detected between ventricular events sensed on left ventricular (LV) and right ventricular (RV) sensing channels. Preferred or optimal ventricular pacing delays are then determined, in part, based on a comparison of the relative degrees of variation obtained during the V sense test. In another example, during RV and LV pace tests, the device distinguishes QRS complexes arising due to interventricular conduction from QRS complexes arising due to atrioventricular conduction from the atria, so as to permit the determination of correct paced interventricular conduction delays for the patient. The paced interventricular conduction delays are also used to optimize ventricular pacing.

Abstract: A method and apparatus for controlling an atrial overdrive pacing therapy include detecting an atrial arrhythmia episode and determining if the atrial arrhythmia episode is an early recurring episode. Delivery of the atrial overdrive pacing therapy is enabled in response to the early recurring episode and commences upon detection of an atrial arrhythmia episode or a long pause.

Abstract: Implantable systems and method for use therewith are provided that take advantage of various neuromodulation and neurosensing techniques for either preventing atrial fibrillation (AF) or terminating AF. Specific embodiments are for use with an implantable device that includes one or more atrial electrode for sensing atrial fibrillation (AF) and/or delivering AATP and one or more electrode for monitoring and/or stimulating atrial vagal fat pads.

Abstract: A method for operating a cardiac pacemaker in which the mode of operation of the pacemaker is altered in response to detecting an episode of atrial tachycardia. In accordance with the invention, the pacemaker's pacing mode is altered in a manner that attempts to maintain hemodynamic stability during the atrial tachycardia. Such a mode switch is particularly applicable to pacemaker patients suffering from some degree of congestive heart failure.

Abstract: A system including at least one implantable sensor circuit adapted to produce an electrical sensor signal related to one or more physiologic cardiovascular events of a subject, a therapy circuit configured to provide anti-tachycardia pacing (ATP) therapy, and a controller. The controller includes a tachyarrhythmia detection circuit and an efficacy circuit. The tachyarrhythmia detection circuit is configured to detect a tachyarrhythmia episode in the subject using the electrical sensor signal, and to determine whether the tachyarrhythmia episode is of a type that is treatable with ATP. The efficacy circuit is configured to estimate an efficacy of a currently configured ATP therapy for the subject, and the controller is configured to alter a delivery regimen of the currently configured ATP therapy when the estimated ATP therapy efficacy is deemed insufficient. Other systems and methods are described.

Abstract: A cardiac rhythm management system provides both a safe maximum pacing rate limit and a physiological maximum pacing rate limit. In one embodiment, a normal maximum tracking rate (MTR) and a hysteresis MTR are provided. The hysteresis MTR is set higher than the normal MTR and functions as a maximum pacing rate. When an atrial rate exceeds the hysteresis MTR limit, the maximum pacing rate limit is set to the normal MTR. Once the atrial rate falls below a predetermined threshold, the maximum pacing rate limit is set to the hysteresis MTR. This provides for a more rapid and natural maximum pacing rate limit for a patient, while still protecting the patient from being paced at abnormally high rates.

Abstract: A cardiac rhythm management (CRM) system includes an implantable medical device that delivers anti-tachyarrhythmia therapies including anti-tachyarrhythmia pacing (ATP) and a hemodynamic sensor that senses a hemodynamic signal. The implantable medical device includes a hemodynamic sensor-controlled closed-loop ATP system that uses the hemodynamic signal for ATP capture verification. When ATP pulses are delivered according to a selected ATP protocol to terminate a tachyarrhythmia episode, the implantable medical device performs the ATP capture verification by detecting an effective cardiac contraction from the hemodynamic signal. The ATP protocol is adjusted using an outcome of the ATP capture verification.

Abstract: A system (10) for achieving a desired cardiac rate and cardiac rhythm in response to atrial fibrillation in a heart includes an atrial fibrillation (AF) detector (40) for detecting AF. The system also includes an atrioventricular node vagal stimulator (AVN-VS) (30) for stimulating vagal nerves associated with an atrioventricular (AV) node of the heart. The system further includes an on-demand pace maker (40) for providing ventricular pacing stimulation to the heart. A control unit (20) is operatively connected with the AF detection device, the AVN-VS device, and the on-demand pacing device. The control unit is responsive to AF detection by the AF detector to cause the AVN-VS to stimulate the vagal nerves to help reduce the ventricular rate of the heart. The control unit is further responsive to AF detection by the AF detector to cause the on-demand pace maker to help regulate the ventricular rate of the heart.

Abstract: A method for operating a cardiac pacemaker in which the mode of operation of the pacemaker is altered in response to detecting an episode of atrial tachycardia. In accordance with the invention, the pacemaker's pacing mode is altered in a manner that attempts to maintain hemodynamic stability during the atrial tachycardia. Such a mode switch is particularly applicable to pacemaker patients suffering from some degree of congestive heart failure.

Abstract: An exemplary method includes detecting arrhythmia, detecting myocardial ischemia, determining whether the myocardial ischemia comprises local ischemia or global ischemia and, in response to the determining, calling for delivery of either a local ischemic anti-arrhythmia therapy or a global ischemic anti-arrhythmia therapy. Various other exemplary methods, devices, systems, etc., are also disclosed.

Abstract: An apparatus comprises an implantable cardiac signal sensing circuit configured to produce a sensed cardiac signal representative of cardiac activity of a subject and a controller communicatively coupled to the cardiac signal sensing circuit. The controller includes a sensing module configured to detect a cardiac depolarization using the sensed cardiac signal and an arrhythmia detection module. The arrhythmia detection module is configured to detect a depolarization rate or interval that satisfies a first tachyarrhythmia detection rate zone threshold, adjust a specified detection duration threshold for the tachyarrhythmia detection zone according to the detected depolarization rate, declare that the detected depolarization rate is an episode of tachyarrhythmia when the detected depolarization rate is sustained for the adjusted detection duration threshold, and provide an indication of the tachyarrhythmia to a user or process.

Abstract: Vagal stimulation applied to the atrioventricular nodal (“AVN”) fat pad and the sinoatrial nodal (“SAN”) fat pad via epicardial leads is useful for controlling cardiac arrhythmia, including atrial fibrillation (‘AF”). In the case of AF, for example, vagal stimulation may be applied initially to the AVN fat pad to reduce ventricular rate, and vagal stimulation may be applied to the SAN fat pad after restoration of sinus rhythm to control atrial rate. The technique is applicable to control acute AF and chronic AF. The vagal stimulation may be optimized for exciting ganglia in the fat pads to produce dromotropic and chronotropic effects in the atrioventricular node and the sinoatrial node, respectively. In addition, the SAN fat lead can also be used to pace the atrium in case of sinus bradycardia.

Abstract: An implantable system terminates atrial fibrillation by applying optimized anti-tachycardia pacing (ATP). In one implementation, the system senses and paces at multiple sites on the left atrium. At each site, the system senses reentrant circuits causing the atrial fibrillation. In one implementation, the system applies ATP tuned to the frequency of the reentrant circuit at the electrode that senses the most regular reentrant circuit. In another implementation, the system applies ATP at multiple electrodes, delivering each pulse at each site when the excitable gap is near the site. In other variations, the ATP is optimized for different patterns of sequential, simultaneous, or syncopated delivery to terminate the atrial fibrillation. The system can also monitor multiple heart chambers for cardiac events that favor terminating atrial fibrillation via ATP. The system then times delivery of the ATP according to these cardiac events.

Abstract: A system and method for controlling cardiac ventricular tachyarrhythmias by acquiring a pressure signal representative of coronary venous pressure (CVP) from a pressure sensor implanted within a coronary vein of the patient. A CVP index is derived based on the pressure signal. The onset of a ventricular tachyarrhythmia episode is detected based on a cardiac rates signal. The CVP index and the rate signal are monitored and, responsive to the rate signal indicating a sustained tachycardia episode during the episode monitoring period, anti-tachycardia therapy selectively withheld and the episode monitoring period is extended based on the CVP index.

Abstract: This document discusses, among other things, an apparatus comprising an atrial sensing circuit, a ventricular sensing circuit and an atrioventricular (AV) delay adjustment circuit. The atrial sensing circuit detects a first fast atrial pace that concludes a timing interval that is shorter than or equal to a first threshold value. The ventricular sensing circuit detects a first condition that comprises a sensed intrinsic first fast ventricular contraction that occurs within a specified first period of a most recently detected first fast atrial pace. The fast ventricular contraction concludes a timing interval that is shorter than or equal to a second threshold value. The AV delay adjustment circuit attempts to decrease an AV delay at least in part in response to detecting the first condition. Other apparatuses and methods are disclosed.

Abstract: A cardiac rhythm management (CRM) system includes an implantable medical device that delivers anti-tachyarrhythmia therapies including anti-tachyarrhythmia pacing (ATP) and at least one hemodynamic sensor that senses a hemodynamic signal. When a tachyarrhythmia episode is detected, the CRM system analyzes the hemodynamic signal to determine whether and/or when to deliver an ATP. In one embodiment, a hemodynamic parameter extracted from the hemodynamic signal is used to predict the potential effectiveness of ATP in terminating the detected tachyarrhythmia episode. In another embodiment, a characteristic feature detected from the hemodynamic signal is used to determine an ATP window during which a delivery of ATP is initiated.

Abstract: A method and apparatus for reducing a patient's heart rate or blood pressure. The apparatus provides stimulation to the patient's atrial and/or nodal tissue within the associated refractory period of the ventricle but outside of an associated refractory period of the stimulated atrial an/or nodal tissue, responsive to detecting an occurrence of a ventricular depolarization following a preceding atrial depolarization. The apparatus may define a time window following the ventricular depolarization, following the atrial depolarization or determined based upon the timing of both the atrial and ventricular depolarizations. The stimulus may be delivered during or on expiration of the defined time window. The duration of the time window may be pre-set or determined based upon measurements of the patient's refractory periods.

Abstract: This document discusses, among other things, detection of a sudden onset of a tachyarrhythmia. A sudden onset of tachyarrhythmia is determined by monitoring changes in intrinsic ventricular rate, such as by using one or more sensing channels in the ICD. A lowest tachyarrhythmia rate threshold is accompanied by a slightly lower “hysteresis tachyarrhythmia rate threshold.” If a sudden onset of tachyarrhythmia is declared, the sudden onset status is not reset by the ventricular rate falling below the lowest tachyarrhythmia rate threshold, but is instead reset by the ventricular rate falling below the slightly lower hysteresis tachyarrhythmia rate threshold.

Abstract: Systems and methods to inhibit the conduction of certain spurious electrical impulses in the heart. Inhibition of spurious electrical impulses in the heart is accomplished by cooling one or more targeted portions of the heart. Optionally, inhibition of spurious electrical impulses may be accomplished by cooling of cardiac tissue in combination with pacing of the heart.

Abstract: An implantable cardiac stimulation device promotes intrinsic activity of a heart during demand pacing. The device increases the time and probability of an AV delay interval extension. The device may further increase the AV delay interval from a first extended AV delay interval to a longer second extended AV delay interval. The device may further encourage intrinsic AV conduction in patients with intact AV conduction by allowing multiple cycles during a search interval and multiple search times to further encourage intrinsic conduction from the atrium to the ventricle.