This document discusses, among other things, systems and methods to determine a response between received cardiac electrical information from a subject, such as a time of a P wave, and received cardiac acceleration information of the subject, such as a time of a first heart sound (S1) or a second heart sound (S2), across a set of stimulation signals provided to the subject at different AVD intervals, and determining one or more cardiac resynchronization therapy (CRT) parameters using an inflection point of the determined response.

Cardiac pacing is performed using leadless pacemakers (LPs). An AV delay is determined based on a P-wave duration. When pacing occurs during cardiac cycles starting with intrinsic atrial events, the AV delay is set to the P-wave duration plus a first offset if the P-wave duration is greater than a first threshold duration, and the AV delay is set to the P-wave duration plus a second offset that is greater than the first offset, if the P-wave duration is less than the first threshold duration. When pacing occurs during cardiac cycles starting with paced atrial events, the AV delay is set to the P-wave duration plus a third offset, if the P-wave duration is greater than a second threshold duration, or is set to the P-wave duration plus a fourth offset that is greater than the third offset, if the P-wave duration is less than the second threshold duration.

Methods and systems are provided for a rate adaptive bi-ventricular fusion pacing. The methods and systems deliver a first pulse at a left ventricular (LV) lead and a second pulse at a right ventricular (RV) lead based on a paced atrio-ventricular (AV) delay. The first pulse timed to be delivered concurrently with an intrinsic ventricular conduction. The methods and systems further repeat the delivery of the first pulse and the second pulse for a predetermined number of cycles. Additionally, the methods and systems measure an intrinsic AV conduction interval, and adjust the paced AV delay based on the intrinsic AV conduction interval and a negative hysteresis delta.

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.

This document discusses, among other things, systems and methods to determine a response curve between received cardiac electrical information from a subject, such as a time of a P wave, and received cardiac acceleration information of the subject, such as a time of a first heart sound (S1) or a second heart sound (S2), to a set of stimulation signals provided to the subject at different AVD intervals. In certain examples, one or more cardiac resynchronization therapy (CRT) parameters can be determined for the subject using the determined response curve.

Systems and methods for controlling blood pressure by controlling atrial pressure and atrial stretch are disclosed. In some embodiments, a stimulation circuit may be configured to deliver a stimulation pulse to at least one cardiac chamber of a heart of a patient, and at least one controller may be configured to execute delivery of one or more stimulation patterns of stimulation pulses to the at least one cardiac chamber, wherein at least one of the stimulation pulses stimulates the heart such that an atrial pressure resulting from atrial contraction of an atrium overlaps in time a passive pressure build-up of the atrium, such that an atrial pressure of the atrium resulting from the stimulation is a combination of the atrial pressure resulting from atrial contraction and the passive pressure build-up and is higher than an atrial pressure of the atrium would be without the stimulation, and such that the blood pressure of the patient is reduced.

A medical device system and associated method predict a patient response to a cardiac therapy. The system includes for delivering cardiac pacing pulses to a patient's heart coupled to a cardiac sensing module and a cardiac pacing module for generating cardiac pacing pulses and controlling delivery of the pacing pulses at multiple pace parameter settings. An acoustical sensor obtains heart sound signals. A processor is enabled to receive the heart sound signals, derive a plurality of heart sound signal parameters from the heart sound signals, and determine a trend of each of the plurality of heart sound signal parameters with respect to the plurality of pace parameter settings. An external display is configured to present the trend of at least one heart sound parameter with respect to the plurality of pace parameter settings.

An intracardiac ventricular pacemaker is configured to detect a ventricular diastolic event from a motion signal received by a pacemaker control circuit from a motion sensor. The control circuit starts an atrial refractory period having an expiration time set based on a time of the detection of the ventricular diastolic event. The control circuit detects an atrial systolic event from the motion signal after expiration of the atrial refractory period and controls a pulse generator of the pacemaker to deliver a pacing pulse to a ventricle of a patient's heart at a first atrioventricular pacing time interval after the atrial systolic event detection.

Some embodiments of pacing systems employ wireless electrode assemblies to provide pacing therapy. The wireless electrode assemblies may wirelessly receive energy via an inductive coupling so as to provide electrical stimulation to the surrounding heart tissue. In certain embodiments, the wireless electrode assembly may include one or more biased tines that shift from a first position to a second position to secure the wireless electrode assembly into the inner wall of the heart chamber.

An implantable medical device for stimulating a human/animal heart, comprising a housing, a processor, a memory unit, a stimulation unit configured to stimulate the His bundle, and a detection unit configured to detect an electrical signal at the His bundle. The device performs: a) stimulating the His bundle with a stimulation pulse delivered by the stimulation unit; b) measuring an electric signal at the His bundle with the detection unit upon termination of a first period of time starting upon delivering of the stimulation pulse, wherein the first period of time is from 35 ms to 500 ms; c) measuring an impedance of the same heart with the detection unit upon termination of a second period of time starting upon delivering of the stimulation pulse, wherein the second period of time is equal to or longer than the first period of time and is from 50 ms to 500 ms.