An intracardiac ventricular pacemaker having a motion sensor, a pulse generator and a control circuit coupled to the pulse generator and the motion sensor is configured to identify a ventricular systolic event, detect a ventricular passive filling event signal from the motion signal, and determine a time interval from the ventricular systolic event to the ventricular passive filling event. The pacemaker establishes a minimum pacing interval based on the time interval.

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.

An intracardiac pacemaker system is configured to produce physiological atrial event signals by a sensing circuit of a ventricular intracardiac pacemaker and select a first atrial event input as the physiological atrial event signals. The ventricular intracardiac pacemaker detects atrial events from the selected first atrial event input, determines if input switching criteria are met, and switches from the first atrial event input to a second atrial event input in response to the input switching criteria being met. The second atrial event input includes broadcast atrial event signals produced by a second implantable medical device and received by the ventricular intracardiac pacemaker.

In some examples, controlling delivery of cardiac resynchronization therapy (CRT) includes storing, in a memory of an implantable medical device system and in association with each of a plurality of heart rates, at least one respective value for an interval between an atrial event and a ventricular event. Processing circuitry of the implantable medical device system may determine a heart rate of a patient and select one of the stored values for the interval between the atrial event and the ventricular event associated with the determined heart rate. The processing circuitry may further determine whether to control therapy delivery circuitry of the implantable medical device system to deliver fusion pacing or biventricular pacing, based on the selected one of the stored values for the interval between the atrial event and the ventricular event.

A method and device for dynamic device based AV delay adjustment are provided. The method provides electrodes that are configured to be located proximate to an atrial (A) site and a right ventricular (RV) site. The method utilizes one or more processors, in an implantable medical device (IMD), for detecting an atrial paced (Ap) event or atrial sensed (As) event. The method determines a measured AV interval corresponding to an interval between the Ap event or the As event and a ventricular sensed event and calculates a percentage-based (PB) offset based on the measured AV interval. The method automatically dynamically adjusting an AV delay, utilized by the IMD, based on the measured AV interval and the PB offset and manages a pacing therapy, utilized by the IMD, based on the AV delay after the adjusting operation.

Devices and methods for improving device therapy such as cardiac resynchronization therapy by determining a value for a device parameter are described. An ambulatory medical device (AMD) can include a sensor circuit to sense a physiological signal and generate two or more signal metrics, and detect an event of worsening cardiac condition using the two or more signal metrics. In response to the detection of worsening cardiac condition, the AMD can determine, for a stimulator, a value of at least one stimulation parameter based on temporal responses of two or more signal metrics. The temporal responses include near-term and long-term responses to the stimulation. The AMD can program the stimulator with the determined parameter value, and generate stimulation according to the determined parameter value to stimulate target tissue.

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 computer implemented method and device for providing dual chamber sensing with a single chamber leadless implantable medical device (LIMD) are provided. The method is under control of one or more processors in the LIMD configured with specific executable instructions. The method obtains a far field (FF) cardiac activity (CA) signals for activity in a remote chamber of a heart and compares the far field CA signals to a P-wave template to identify an event of interest associated with the remote chamber. The method sets an atrial-ventricular (AV) delay based on the P-wave identified and delivers pacing pulses at a pacing site of interest to a local chamber based on the AV delay.

A leadless pacing device may include a power supply providing a power supply voltage, a housing having a first end, a second end, and a side extending between the first end and the second end, and a set of electrodes supported by the housing and in communication with the power supply. The housing may be angled to follow a contour of a patient's heart when the housing is positioned within the coronary sinus of the patient's heart. In some cases, an angled portion of the housing may include a smooth-curve. In some cases, an angled portion of the housing may include a first portion of the housing and a second portion of the housing at an angle of less than one-hundred-eighty degrees with respect to the first portion of the housing. One or more of the electrodes may be exposed on a concave side of the angled housing.

The invention provides methods related to improving heart function.