Abstract: A triggered mode pacing system enables dual chamber sensing. The system also determines whether a cardiac event is initially sensed in a first cardiac chamber or a second cardiac chamber. The system then triggers an output to the second cardiac chamber in response to sensing the cardiac event in the first cardiac chamber when the cardiac event was determined to have been initially sensed in the first cardiac chamber.

Abstract: A method and apparatus for treatment of hypertension and heart failure by increasing secretion of endogenous atrial hormones by pacing of the heart atria. Atrial pacing is done during the ventricular refractory period resulting in premature atrial contraction that does not result in ventricular contraction. Pacing results in the atrial wall stress, peripheral vasodilation, ANP secretion. Concomitant reduction of the heart rate is monitored and controlled as needed with backup pacing.

Abstract: Methods and systems are provided to deliver a neural stimulation (NS) therapy utilizing a first NS operating configuration to assist anti-tachycardia pacing (ATP) therapy in response to a detected tachyarrhythmia. Before and after delivering of the NS therapy, characteristic values are measured for a rate-related physiologic characteristic (rate RPC) and a stability-related physiologic characteristic (stability RPC). The rate RPC is indicative of a frequency of a reentrant circuit within the tachyarrhythmia. The stability RPC is indicative of a hemodynamic stability of the reentrant circuit. The pre-NS and post-NS characteristic values for the rate and stability RPCs are analyzed to determine a rate RPC difference and a stability RPC difference. Different ATP therapies are delivered based on the type associated with the tachyarrhythmia, the rate RPC difference and the stability RPC difference.

Abstract: An implantable medical device (IMD) identifies suspected non-lethal ventricular arrhythmia, and takes one or more actions in response to the identification to avoid or delay delivery of a defibrillation or cardioversion shock. The IMD employs number of intervals to detect (NID) thresholds for detection of ventricular arrhythmias. When a NID threshold is met, the IMD determines whether the ventricular rhythm is a suspected non-lethal rhythm despite satisfying a NID threshold. In some embodiments, the IMD increases the NID threshold, i.e., extends the time for detection, in response to identifying a rhythm as a suspected non-lethal rhythm, and monitors subsequent ventricular beats to determine if the increased NID threshold is met before detecting a ventricular arrhythmia and delivering therapy. The IMD can determine whether a rhythm is a suspected non-lethal arrhythmia by, for example, comparing the median ventricular cycle length (VCL) to the median atrial cycle length (ACL).

Abstract: A method for analysis of cardiac rhythm and RR interval time series based on entropy related data and entropy based measures. The information is related to but distinct from entropy, and is derived from histograms of interval match counts in which the y-axis is the frequency of intervals of length in that have the match count given on the x-axis. The phenotype of the histogram informs on the presence of atrial fibrillation or, in the presence of sinus rhythm, the degree of congestive heart failure.

Abstract: A triggered mode pacing system enables dual chamber sensing. The system also determines whether a cardiac event is initially sensed in a first cardiac chamber or a second cardiac chamber. The system then triggers an output to the second cardiac chamber in response to sensing the cardiac event in the first cardiac chamber when the cardiac event was determined to have been initially sensed in the first cardiac chamber.

Abstract: Dual chamber pacemaker systems can lead to two forms of pacemaker-facilitated tachycardia—pacemaker-mediated tachycardia (PMT) and tracking of sinus or atrial tachycardia. Current pacemaker algorithms can not always differentiate between these two tachycardias. Various embodiments for differentiating these particular mechanisms of pacemaker-facilitated tachycardia, which is based on the specific termination response to PVARP extension are provided. The response to PVARP extension (V-A-A-V vs V-A-V) is a specific method for differentiation and can be used in conjunction with observations of atrial rate and electrogram morphology (or surface P wave morphology) for distinguishing between the two mechanisms of pacemaker-facilitated tachycardia.

Abstract: Techniques are provided for use with implantable cardiac stimulation devices equipped for multi-site left ventricular (MSLV) cardiac pacing. Briefly, intraventricular and interventricular conduction delays are detected for paced cardiac events. Maximum pacing time delays are determined for use with MSLV pacing where the maximum pacing time delays are set based on the conduction delays to values sufficient to avoid capture problems due to wavefront propagation, such as fusion or lack of capture. MSLV pacing delays are then set to values no greater than the maximum pacing delays and cardiac resynchronization therapy (CRT) is delivered using the MSLV pacing delays. In an example where an optimal interventricular pacing delay (VV) is determined in advance using intracardiac electrogram-based or hemodynamic-based optimization techniques, the optimal value for VV can be used as a limiting factor when determining the maximum MSLV pacing time delays.

Abstract: A method and device for delivering multi-site ventricular pacing therapy in conjunction with parasympathetic stimulation for reducing ventricular wall stress. Such reduction in ventricular wall stress is useful in reversing or preventing the ventricular remodeling which can occur in heart failure patients.

Abstract: Systems including an implantable receiver-stimulator and an implantable controller-transmitter are used for leadless electrical stimulation of body tissues. Cardiac pacing and arrhythmia control is accomplished with one or more implantable receiver-stimulators and an external or implantable controller-transmitter. Systems are implanted by testing external or implantable devices at different tissue sites, observing physiologic and device responses, and selecting sites with preferred performance for implanting the systems. In these systems, a controller-transmitter is activated at a remote tissue location to transmit/deliver acoustic energy through the body to a receiver-stimulator at a target tissue location. The receiver-stimulator converts the acoustic energy to electrical energy for electrical stimulation of the body tissue. The tissue locations(s) can be optimized by moving either or both of the controller-transmitter and the receiver-stimulator to determine the best patient and device responses.

Abstract: Method and apparatus for preventing heart rhythm disturbances by recording cardiac electrical activity, measuring beat-to-beat variability in the morphology of electrocardiographic waveforms, and using the measured beat-to-beat variability to control the delivery of electrical impulses to the heart during the absolute refractory period.

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: An active implantable medical device of the cardiac prosthesis type, including antitachycardia atrial pacing and antibradycardia ventricular pacing therapies. The device includes circuits and control logic for detecting electrical atrial and ventricular spontaneous events (R), delivering low energy antitachycardia atrial pacing, and antibradycardia ventricular pacing, and able to deliver a ventricular pacing (V) in the absence of a detected spontaneous ventricular event (R) after a calculated ventricular escape interval (IE). The device includes a sensor delivering an endocardiac acceleration signal (EA) representative of the movements produced by the contractions of the ventricle.

Abstract: Provided herein are implantable systems, and methods for use therewith, for characterizing a tachycardia and/or selecting treatment for a tachycardia using results of a fractionation analysis. One or more electrogram (EGM) signal(s) indicative of cardiac electrical activity are obtained. At least one of the EGM signal(s) is analyzed to determine whether the EGM signal is fractionated, and the results of the analyzing are used to characterize a tachycardia and/or to select treatment for a tachycardia.

Abstract: A device senses cardioelectrical signals using a right atrial (RA) lead, which might include far-field R-waves as well as near-field P-waves. The device concurrently senses events using a proximal electrode of an LV lead, which can sense both P-waves and R-waves as substantially near-field events. Suitable templates are then applied to the signals sensed via the proximal LV electrode to identify the origin of the signals (e.g. atrial vs. ventricular) so as to properly classify the corresponding events sensed in the RA as near-field or far-field events. In this manner, far-field oversensing is conveniently detected.

Abstract: Techniques for reducing inappropriate tachyarrhythmia therapy and associated medical device systems are described. In some examples a processor is enabled to receive a cardiac electrical signal representative of electrical activity of a heart of a patient and provide an indication of cardiac electrical signal reliability. A heart sound analyzing module is enabled to receive the indication of cardiac electrical signal reliability and a heart sound signal representing sounds generated by the heart of the patient and generated by a heart sound sensor. The heart sound analyzing module selectively determines an ensemble averaged heart sound signal or detects a plurality of heart sounds from the heart sound signal in response to the indication of cardiac electrical signal reliability.

Abstract: An electrotherapy system, particularly an implantable heart stimulator, is configured as an electronic implant for electrical anti-tachycardia therapy of the heart, and includes at least one programmable therapy sequence (i.e. a sequence of several therapies that are delivered, one after the other, to treat a VT/VF episode). The implant has a therapy success memory for storing therapy success statistics for each therapy, as well as a therapy control unit that is configured to automatically undertake adaptation of the order of the therapies within a therapy sequence as a function of currently stored therapy success statistics.

Abstract: Cardiac arrhythmias are classified based on the morphology of the arrhythmia episode beats. Templates are formed using morphological features of the cardiac beats of the episode. The arrhythmia episode is classified as a monomorphic tachyarrhythmia or polymorphic tachyarrhythmia based on the one or more templates. The arrhythmia episode may be classified based on a number templates formed from the arrhythmia episode. The templates are formed by determining a measure of similarity between morphological features of a cardiac beat to a template. The similarities can be determined based on a pairing rule that determines which beat morphologies are compared. Selection of therapy for treating the arrhythmia episode may depend on the historical success of a therapy at mitigating previous arrhythmias of the same type as the arrhythmia episode.

Abstract: An implantable sensor circuit can be configured to generate a first sensor signal representative of mechanical activation of a first chamber of a heart of a subject and a second sensor signal representative of mechanical activation of a second chamber of the heart. A chamber synchrony measurement circuit can be configured to generate a measure of synchrony of the mechanical activations of the first heart chamber and the second heart chamber using the first and second sensor signals, a tachyarrhythmia detector circuit, and a control circuit. The control circuit can be configured to receive an indication of a detected episode of tachyarrhythmia, and to initiate, select, or adjust a device-based therapy at least in part using the measure of synchrony of the mechanical activations in response to the tachyarrhythmia detection.

Abstract: An implantable medical device can establish one or more artificial conduction pathways during tachyarrhythmia. Withdrawal of the artificial conduction pathway may help self-terminate the tachyarrhythmia, or may pre-condition the tachyarrhythmia to be more favorable for receiving an anti-tachyarrhythmia therapy, such as anti-tachyarrhythmia pacing, defibrillation shock therapy, or cardioversion. This can help provide enhanced anti-tachyarrhythmia therapy.

Abstract: The present disclosure is directed to the classification of cardiac episodes using an algorithm. In various examples, an episode classification algorithm evaluates electrogram signal data using a probabilistic ventricular oversensing algorithm. The algorithm may look at a plurality of factors weighing for and against a determination of ventricular oversensing. In some examples, the algorithm may also determine whether the cardiac episode includes atrial sensing issues.

Abstract: Embodiments of the present invention relate to monitoring a patient's atrial stretch, heart failure (HF) condition, and/or risk of atrial fibrillation (AF), as well as methods for estimating a change in at least one of a patient's left atrial pressure (LAP), pulmonary capillary wedge pressure (PCWP), and right pulmonary artery pressure (RPAP). Embodiments of the present invention also relate to selecting a pacing energy level. Such embodiments involve determining atrial evoked response metrics when a patient's atrium is paced, and monitoring changes in such metrics.

Abstract: An apparatus example comprises a cardiac signal sensing circuit configured to provide a sensed cardiac signal representative of cardiac depolarization events of a subject, a sampling circuit coupled to the cardiac signal sensing circuit, a therapy circuit, and a controller communicatively coupled to the sampling circuit and the therapy circuit. The controller includes a detection module configured to detect tachyarrhythmia using the cardiac signal and a signal analysis module configured to establish significant points (SPs) of the sampled cardiac signal, estimate heart rate during the tachyarrhythmia using the SPs, and provide an indication of whether noise is present in the cardiac signal using the SPs. The controller is configured to select a therapy for delivery by the therapy circuit in response to the tachyarrhythmia detection and to modify the selected therapy according to the heart rate estimation and the noise indication.

Abstract: A cardiac rhythm management system identifies a relationship between one or more hemodynamic parameters sensed from a patient and levels of hemodynamic tolerability of the patient. The identified relationship allows an implantable medical device to control delivery of anti-tachyarrhythmia therapy using the patient's hemodynamic tolerability during a detected tachyarrhythmia episode, in addition to classifying the detected tachyarrhythmia episode by its type and origin.

Abstract: Various techniques for delivering atrial pacing and supraventricular stimulation to achieve a desired ventricular rate and/or cardiac output are described. One example method described includes delivering a pacing signal configured to cause an atrial depolarization to a heart of a patient, wherein the atrial depolarization results in an associated refractory period during the cardiac cycle, and delivering a signal to a supraventricular portion of the heart of the patient subsequent to the atrial refractory period and during a ventricular refractory period of the cardiac cycle.

Abstract: Devices and methods are described for treating maladies such as atrial fibrillation. The devices and methods, in some implementations, include implant comprising a ribbon or other structure formed into one or more rings. The ribbon can provide mechanical pressure against an adjacent tissue, e.g., the tissue of a vessel, so as to help at least partially inhibit the propagation of electrical signals along the vessel.

Abstract: At least one embodiment of the invention relates to an implantable electronic device, comprising a heart rhythm detection unit, a respiratory dynamics detection unit, an evaluation unit and at least one connection to at least two electrode poles. The at least two electrode poles are connected to the heart rhythm detection unit, and the heart rhythm detection unit is configured to supply a heart rhythm signal representing the heart rhythm as an output signal. The at least two electrode poles are connected to a respiratory dynamics determination unit, and the respiratory dynamics detection unit is configured to supply a respiratory dynamics signal representing the respiratory dynamics as the output signal. Moreover, the heart rhythm detection unit and the respiratory dynamics detection unit are connected to the evaluation unit, and the evaluation unit is configured to evaluate the heart rhythm signal in conjunction a temporally associated respective respiratory dynamics signals.

Abstract: A medical device having a unit in communication with ancillary components wherein the unit and the ancillary components each have a sensory output through which communication with a user of the medical device may be accomplished and to which the user's attention directed. In one aspect, the medical device is an AED unit with associated pads, which are an ancillary component electrically connected to the AED unit. In this illustrative example, the unit has a unit sensory output (e.g., a speaker or a display), and the pads, and/or their associated packaging, have an ancillary sensory output (e.g. a speaker or display). Programming in the AED unit controls output to the sensory outputs such that the user's attention is directed between the unit and the ancillary components.

Abstract: Apparatus and methods for pacing the heart. The apparatus may include, and the methods may involve, an elongated member having: a delivery lumen that is configured to traverse the heart wall, the lumen having a proximal opening for receiving the instrument and a distal opening for deploying the instrument; and an electrically conductive member that is configured to deliver to the heart wall a current that modifies a contraction frequency. The apparatus may include an access opening closure device that has: a distal end that is configured to be disposed interior the heart and contact endocardial tissue adjacent the access opening; and a proximal end that is configured to be disposed exterior the heart and contact heart tissue adjacent the access opening; and an electrode that is configured to discharge electrical energy into the heart wall to change the frequency. The apparatus may include an injectable needle pacing electrode.

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: 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: An apparatus comprises an implantable cardiac signal sensing circuit and a controller circuit. The implantable cardiac signal sensing circuit provides a sensed depolarization signal from a ventricle and a sensed depolarization signal from an atrium. The controller circuit includes a one-to-one detector circuit and a tachyarrhythmia discrimination circuit. The one-to-one detector circuit measures cardiac depolarization intervals of the atrium and the ventricle and determines whether a relationship of atrial depolarizations to ventricular depolarizations is substantially one-to-one. The tachyarrhythmia discrimination circuit classifies the episode as VT when detecting a shortening or prolonging of a V-V interval that immediately precedes the same shortening or prolonging of an A-A interval.

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 Atrial Anti-Tachycardia Pacing (AATP) and one or more electrode for monitoring and/or stimulating atrial vagal fat pads.

Abstract: A method and apparatus for delivering therapy to treat ventricular tachyarrhythmias is described. In one embodiment, neural stimulation, anti-tachycardia pacing, and shock therapy are employed in a progressive sequence upon detection of a ventricular tachycardia.

Abstract: Methods, devices, and processor-readable storage media are provided for detecting spontaneous ventricular events in a heart using implantable medical devices. A method in this context includes applying a sensitivity function to collected data to detect occurrence of ventricular events. The sensitivity function is based on an adjustable detection threshold. The method further includes determining whether noise is suspected to be present in the data and, if so, increasing the threshold. The method further includes providing a stimulation pulse to the heart when a ventricular event has not occurred after a predetermined escape interval and, following the stimulation pulse, applying a capture test to detect whether an induced depolarization has occurred. If induced polarization is not detected, the threshold is reduced, while the threshold is maintained if induced polarization is detected.

Abstract: Systems and methods are provided for use by implantable medical devices equipped to deliver multi-site left ventricular (MSLV) pacing. MSLV is associated with a relatively long post-ventricular atrial blanking (PVAB) period that might limit the detection of pathologic rapid organized atrial tachycardias (OAT). In one example, MSLV cardiac resynchronization therapy (CRT) pacing is delivered within a tracking mode. A possible atrial tachycardia is detected based on the atrial rate exceeding an atrial tachycardia assessment rate (ATAR) threshold. The device then switches to single-site LV pacing, thereby effectively shortening the PVAB to detect additional atrial events that might otherwise be obscured, and thereby permitting the device to more reliably distinguish organized atrial tachycardias (such as atrial flutter) from sinus tachycardia.

Abstract: An implantable cardioverter/defibrillator (ICD) delivers atrial pacing under several scenarios during a tachyarrhythmia episode that is detected using a ventricular rate. In various embodiments, the atrial pacing terminates the detected tachyarrhythmia and/or enhances the classification of the detected tachyarrhythmia, thus avoiding ineffective and/or unnecessary delivery of a ventricular anti-tachyarrhythmia therapy when the detected tachyarrhythmia has a supraventricular origin.

Abstract: The present disclosure is directed to the classification of cardiac episodes using an algorithm. In various examples, an episode classification algorithm evaluates electrogram signal data collected by an implantable medical device. The episode classification algorithm may classify may include a sinus template and a comparison of the electrogram signal to the sinus template. Possible classifications of the cardiac episode may include, for example, unknown, inappropriate, appropriate, supraventricular tachycardia, ventricular tachycardia, ventricular fibrillation or ventricular over-sensing.

Abstract: The disclosure describes techniques for diagnosing premature contractions of a patient's heart. This system may differentiate premature atrial contractions (PACs) and premature ventricular contractions (PVCs) from atrial fibrillation by identifying changes in R-wave intervals, i.e., R-R intervals, on a Lorenz plot, measuring a coupling interval between R-waves, and analyzing a morphology of the premature contractions, e.g., the QRS complex. These techniques may also identify when severe premature contractions, or bigeminy, are present. In response to the type of premature contractions detected, the system may alert a user of the premature contractions and/or deliver cardiac pacing at an increased pacing rate to eliminate the abnormal intrinsic contractions. The system may also adjust the pacing rate and pacing rate duration for persistent premature contractions.

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: A method of left ventricular pacing including automated adjustment of a atrio-ventricular (AV) pacing delay interval and intrinsic AV nodal conduction testing. It includes—upon expiration or reset of a programmable AV Evaluation Interval (AVEI)—performing the following: temporarily increasing a paced AV interval and a sensed AV interval and testing for adequate AV conduction and measuring an intrinsic atrio-ventricular (PR) interval for a right ventricular (RV) chamber. In the event that the AV conduction test reveals an AV conduction block condition then a pacing mode-switch to a bi-ventricular (Bi-V) pacing mode occurs and the magnitude of the AVEI is increased.

Abstract: A first chamber minute ventilation rate is determined based on a first transthoracic impedance signal received from a first chamber of a heart and a second chamber minute ventilation rate is determined based on a second transthoracic impedance signal received from a second chamber of the heart. A processor compares the minute ventilation rates to determine a rate. In one embodiment, an accelerometer sensor provides data for evaluating propriety of a rate. Before implementing a rate change, signals from multiple sensors are cross-checked.

Abstract: Embodiments of the invention are related to medical devices and methods for delivery high-energy anti-tachycardia therapy to a subject, amongst other things. In an embodiment, the invention includes a medical device including a controller module configured to administer a plurality of electrical pulses to a patient in response to a detected tachycardia, the electrical pulses comprising an amplitude of greater than 3 Volts and less than 40 Volts, the controller configured to modulate the amplitude of the electrical pulses. In an embodiment, the invention includes a method of treating a tachyarrhythmia including administering a first series of electrical pulses to a patient with an implantable medical device, the electrical pulses including an amplitude of greater than 8 Volts and less than 40 Volts, the first series of electrical pulses having an interval of less than about 600 ms in between individual pulses. Other embodiments are also included herein.

Abstract: A system and method provide for detecting atrial arrhythmias within an implantable medical device capable of sensing and pacing at least an atrium of a heart. Arrhythmia of the atrium is detected. In response to detecting atrial arrhythmia, delivery of pacing signals to the atrium is inhibited under certain conditions. While delivery of the pacing signals to the atrium is inhibited, the detected arrhythmia of the atrium is confirmed during a period of further evaluation. Delivery of pacing signals to the atrium is enabled upon ceasing of the atrial arrhythmia. Inhibiting delivery of the pacing signals during atrial arrhythmia evaluation advantageously provides for an increase in the rate at which the detected arrhythmia is confirmed.

Abstract: A pacemaker initiates and times a monitoring interval in response to an event such as a therapy delivery to a patient. The monitoring interval is specified to include a duration of an anticipated acute response to the event, such as vagal surge. One or more physiological parameters indicative of the acute response are detected during the monitoring interval for analyzing therapeutic effect of the event. In various embodiments, one or more pacing parameters are adjusted for a response interval specified to include the duration of the anticipated acute response to allow for the analysis and maximization of the therapeutic effect. In various embodiments, the event includes a session of pacing therapy delivered according to an intermittent cardiac stress augmentation pacing protocol, and the therapeutic effect is analyzed to adjust that protocol.

Abstract: Various aspects of the present subject matter relate to a method. According to various method embodiments, cardiac activity is detected, and neural stimulation is synchronized with a reference event in the detected cardiac activity. Neural stimulation is titrated based on a detected response to the neural stimulation. Other aspects and embodiments are provided herein.

Abstract: To control cardiac arrhythmias such as atrial fibrillation post-operatively, various non-ablative agents include polymers, fibroblasts, neurotoxins, and growth factors are introduced into one or more cardiac fat pads into the atrioventricular nodal fat pad in proximity to the autonomic ganglia therein. Any desired technique may be used for introducing the agent, including injection. The sinoatrial nodal fat pad target site and the atrioventricular nodal fat pad target site are identified using a stimulator, which may have electrodes coupled thereto or which may coupled to electrodes built into a delivery system.

Abstract: An apparatus comprises an implantable cardiac signal sensing circuit, configured to provide a sensed near-field depolarization signal from a ventricle and to provide a sensed a far-field intrinsic atrial signal using a far-field atrial sensing channel, and a controller circuit communicatively coupled to the cardiac signal sensing circuit. The controller circuit includes a P-wave detection module configured to detect an atrial depolarization in the sensed far-field intrinsic atrial signal and a tachyarrhythmia detection module configured to detect an episode of tachyarrhythmia using the sensed near-field depolarization signal and to determine whether the tachyarrhythmia episode is indicative of supraventricular tachycardia (SVT) using the detected atrial depolarization and the sensed near-field depolarization signal.

Abstract: Systems and method for assessing a patient's myocardial electrical stability by pacing a patient's heart using a pacing sequence that includes at least two different types of pacing pulses. The pacing rate used is preferably only slightly above the patient's intrinsic heart rate. A degree of alternans, in a signal (e.g., IEGM or ECG) that is indicative of cardiac activity in response to the pacing sequence, is determined. The degree of alternans can be determined by comparing portions of the signal that are indicative of cardiac activity in response to the first type of pacing pulses to portions of the signal that are indicative of cardiac activity in response to the second type of pacing pulses. The patient's myocardial electrical stability is assessed based on the determined degree of alternans.