Methods and systems for terminating a pacemaker mediated tachycardia (PMT) are described herein. During a period that a PMT is not detected, an implantable system delivers an atrial pacing pulse to an atrial cardiac chamber in response to a PA interval expiring without an intrinsic atrial event being detected during the PA interval. The systems performs atrial sensing to thereby monitor for intrinsic atrial events in the atrial cardiac chamber, performs ventricular sensing to thereby monitor for intrinsic ventricular events in a ventricular cardiac chamber, and detects the PMT. Additionally, the system, in response to the PMT being detected, initiates a PMT PA interval that is shorter than the PA interval that the system would otherwise use for atrial pacing if the PMT was not detected.

Systems and methods for pacing cardiac conductive tissue are described. An embodiment of a medical system includes an electrostimulation circuit to generate His-bundle pacing (HBP) pulses to stimulate a His bundle, and a cardiac event detector to detect a His-bundle activity within a time window following an atrial activity. The cardiac event detector may use a cross-chamber blanking, or an adjustable His-bundle sensing threshold, to avoid or reduce over-sensing of far-field atrial activity and inappropriate inhibition of HBP therapy. The electrostimulation circuit may deliver HBP in the presence of the His-bundle activity. The system may further recognize the detected His-bundle activity as either a FFPW or a valid inhibitory event, and deliver or withhold HBP therapy based on the recognition of the His-bundle activity.

Systems and methods for dynamically controlling His-bundle pacing (HBP) according to an indication of a rate-related or intermittent atrioventricular (AV) block in a subject are disclosed. An exemplary medical system includes an AV conduction monitor to detect an indication of either a presence or an absence of intermittent or rate-related AV conduction disturbance using physiologic information of the subject. In the event that an intermittent or rate-related AV conduction disturbance is present, a control circuit provides a control signal to an electrostimulation circuit to deliver HBP pulses. If there is no indication of intermittent or rate-related AV conduction disturbance, or a previously detected intermittent or rate-related AV conduction disturbance has been terminated, the control circuit withholds or discontinues delivery of the HBP pulses to promote intrinsic ventricular conduction and activation.

A ventricular pacemaker is configured to determine a ventricular rate interval by determining at least one ventricular event interval between two consecutive ventricular events and determine a rate smoothing ventricular pacing interval based on the ventricular rate interval. The pacemaker is further configured to detect an atrial event from a sensor signal and deliver a ventricular pacing pulse in response to detecting the atrial event from the sensor signal. The pacemaker may start the rate smoothing ventricular pacing interval to schedule a next pacing pulse to be delivered upon expiration of the rate smoothing ventricular pacing interval.

An implantable medical device includes a plurality of electrodes to detect electrical activity, a motion detector to detect mechanical activity, and a controller to determine at least one electromechanical interval based on at least one of electrical activity and mechanical activity. The activity detected may be in response to delivering a pacing pulse according to an atrioventricular (AV) pacing interval using the second electrode. The electromechanical interval may be used to adjust the AV pacing interval. The electromechanical interval may be used to determine whether cardiac therapy is acceptable or whether atrial or ventricular remodeling is successful.

Systems, methods, and devices are described herein for evaluation, adjustment, and delivery of adaptive cardiac therapy. The systems, methods, and devices may utilize electrical heterogeneity information to determine and/or select one or more pacing settings and pacing type or configurations for a plurality of different heart rates. The adaptive cardiac therapy may deliver cardiac therapy at selected pacing settings such as, for example, A-V and/or V-V intervals, according to a presently measured heart rate and switch between left ventricular-only or biventricular cardiac pacing therapy also according to the presently measured heart rate.

An implantable system for stimulating a human/animal heart, comprising a processor, a memory unit, a stimulation unit, a sensing unit, and a diagnostic unit. The system carries out: a) detecting whether at least one malfunction state of the system is present; b) checking whether an electrode provided for stimulating a His bundle of a heart is connected to the stimulation unit; c) switching an operating state of the system into a safety mode when a malfunction state was detected, the safety mode selected from a first safety mode and a second safety mode, wherein i) the first safety mode is selected when no electrode provided for stimulating a His bundle of a heart is connected to the stimulation unit, and ii) the second safety mode is selected when an electrode provided for stimulating a His bundle of a heart is connected to the stimulation unit.

A leadless pacemaker device configured to provide for an intra-cardiac pacing, including: processing circuitry configured to generate ventricular pacing signals for stimulating ventricular activity, and a reception device for receiving a sensing signal indicative of an atrial activity, wherein the processing circuitry is configured to detect an atrial event derived from said sensing signal, wherein the atrial event is a valid atrial sense event, where a series of atrial events lie within a range for a normal atrial rate, and/or when the atrial rate variability is within a certain range indicating a regular atrial rhythm, wherein in case a valid atrial sense event is detected, the processing circuitry is further configured to: determine ventricular pacing events according to atrial events, calculate ventricular-atrial time delays, determine a correction value based a measured time delay and the calculated time delay, and adjust the ventricular pacing timing based on the correction value.

Systems and methods for monitoring chronic over-pacing (COP) to the heart are discussed herein. In an embodiment, a system includes a receiver circuit to receive information about pacing rates of a plurality of paced heart beats, and a pacing analyzer circuit to generate a pacing rate distribution using pacing rates of the plurality of the paced heart beats. The pacing rate distribution includes a pacing rate histogram. The pacing analyzer circuit may recognize a morphological pattern from the pacing rate distribution, and detect a COP indication using the extracted feature. A programmer circuit adjusts one or more therapy parameters in response to the detected. COP indication.

A leadless pacemaker device configured to provide for an intra-cardiac pacing, including: processing circuitry configured to generate ventricular pacing signals for stimulating ventricular tissue, and a reception device for receiving a sensing signal indicative of an atrial activity, wherein the processing circuitry is configured to detect an atrial event derived from said sensing signal, wherein the atrial event is a valid atrial sense event, where a series of atrial events lie within a range for a normal atrial rate, and/or when the atrial rate variability is within a certain range indicating a regular atrial rhythm, wherein in case a valid atrial sense event is detected, the processing circuitry is further configured to: determine ventricular pacing events according to atrial events, calculate ventricular-atrial time delays, determine a correction value based a measured time delay and the calculated time delay, and adjust the ventricular pacing timing based on the correction value.