A system is provided for controlling a left univentricular (LUV) pacing therapy using an implantable medical device (IMD). The system also includes one or more processors configured to determine an atrial-ventricular (AV) conduction interval (AR.sub.RV) between the A site and a first RV sensed event at the RV site, determine an inter-ventricular (VV) conduction interval (R.sub.LV-R.sub.RV) between a paced event at the LV site and a second RV sensed event at the RV site, and set a ventricular refractory period (VRP) based on at least one of the AV conduction interval or the VV conduction interval and a predetermined offset. The one or more processors are also configured to blank signals over the RV sensing channel during the VRP.

The control module of a first pacemaker included in an implantable medical device system including the first pacemaker and a second pacemaker is configured to set a pacing escape interval in response to a far field pacing pulse sensed by the first pacemaker. The far field pacing pulse is a pacing pulse delivered by the second pacemaker. The pacing escape interval is allowed to continue without restarting the in response to a far field intrinsic event sensed by the first pacemaker during the pacing escape interval. The first pacemaker delivers a cardiac pacing pulse to the heart upon expiration of the pacing escape interval.

Described herein are methods for use with an implantable system including at least an atrial leadless pacemaker (aLP). Also described herein are specific implementations of an aLP, as well as implantable systems including an aLP. In certain embodiments, the aLP senses a signal from which cardiac activity associated with a ventricular chamber can be detected by the aLP itself based on feature(s) of the sensed signal. The aLP monitors the sensed signal for an intrinsic or paced ventricular activation within a ventricular event monitor window. In response to the aLP detecting an intrinsic or paced ventricular activation itself from the sensed signal within the ventricular event monitor window, the aLP resets an atrial escape interval timer that is used by the aLP to time delivery of an atrial pacing pulse if an intrinsic atrial activation is not detected within an atrial escape interval.

An energy harvester converts into electrical energy the external stresses applied to the implant at the heartbeat rhythm. This harvester includes an inertial unit and a transducer delivering an oscillating electrical signal that is rectified and regulated for powering the implant and charging an energy storage component. The instantaneous variations of this electrical signal are analyzed in a detection window following or preceding a ventricular contraction, to obtain atrial activity information representative of the atrium contribution to the electric signal, in particular information about the presence/absence of a spontaneous atrial contraction, and/or parameters making it possible to determine an atrioventricular delay to be applied if the ventricle has to be stimulated.

An intracardiac ventricular pacemaker having a motion sensor is configured to produce a motion signal including an atrial systolic event and at least one ventricular diastolic event. The pacemaker is configured to set an atrial refractory period, detect a change in a ventricular diastolic event metric and adjust the atrial refractory period in response to detecting the change. The pacemaker sets set an atrioventricular pacing interval in response to detecting the atrial systolic event from the motion signal after expiration of the atrial refractory period.

In some examples, controlling delivery of CRT includes delivering ventricular pacing according to a sequence of different values of at least one of A-V delay or V-V delay, and acquiring one or more electrograms from respective vectors. For each of the different values of the at least one of A-V delay or V-V delay, at least one of a QRS amplitude or a QRS area may be determined based on the one or more electrograms, and a target change in QRS amplitude or QRS area between adjacent ones of the values of the at least one of A-V delay or V-V delay of the sequence may be identified. In response to the identification of the target change, the implantable medical device may deliver the ventricular pacing at a value of the at least one of A-V delay or V-V delay determined based on the identification to provide CRT.

Systems and methods are described for subject rehospitalization management. In an example, multiple physiologic signals can be obtained from a subject using multiple sensors. In response to a hospitalization event, pre-hospitalization characteristics of the multiple physiologic signals can be identified. Post-hospitalization characteristics of the multiple physiologic signals can be identified, including characteristics that differ from their corresponding pre-hospitalization characteristics. Later subsequent physiologic signals can be further monitored after the hospitalization event, such as using the same multiple sensors, and subsequent physiologic signal characteristics can be identified. In an example, a heart failure diagnostic indication can be determined using information about the pre-hospitalization characteristics, the post-hospitalization characteristics, and the subsequent characteristics. Information about relative changes in signal characteristics from multiple sensors can be used to identify particular subject physiologic signals to monitor during subsequent periods.

The present disclosure relates generally to pacing of cardiac tissue, and more particularly to adjusting delivery of His bundle or bundle branch pacing in a cardiac pacing system to achieve synchronized ventricular activation. A left bundle branch (LBB) cathode electrode may be implanted a left side of the septum of the patient's heart proximate to the LBB, and a right bundle branch (RBB) cathode electrode may be implanted on a right side of the septum of the patient's heart proximate to the RBB. One or both cathode electrodes may be used to deliver synchronized left and right bundle-branch pacing based on one or both of an atrial event and a ventricular event. A device for bundle branch pacing may be implanted based on determining whether an LBB block pattern or an RBB block pattern is present in monitored electrical activity.

The present disclosure relates generally to pacing of cardiac tissue, and more particularly to adjusting delivery of His bundle or bundle branch pacing in a cardiac pacing system to achieve synchronized ventricular activation. A leadless pacing device (LPD) may include a plurality of electrodes comprising a bundle pacing electrode leadlessly connected to the housing, which may be implanted proximate to or in the His bundle or bundle branch of the patient's heart. An electrical pulse generator may generate and deliver electrical His-bundle or bundle-branch stimulation pulses using the bundle pacing electrode based on sensing one or both of an atrial event and a ventricular event. The LPD may receive communication from another implantable device, such as a subcutaneously implanted device, and deliver His-bundle or bundle-branch pacing in response to the communication.

The present disclosure relates generally to pacing of cardiac tissue, and more particularly to adjusting delivery of His bundle or bundle branch pacing in a cardiac pacing system to achieve synchronized ventricular activation. Bundle pacing may be delivered in response to determining whether the QRS parameter or activation interval is greater than a threshold. A set of AV delays may be generated, and an optimal AV delay may be selected from the stored set of AV delays. His-bundle or bundle-branch pacing may be selectively delivered based on RV or LV activation time. Pacing may also be adjusted based on dyssynchrony detected or the type of bundle branch block pattern detected.