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.

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.

Systems and methods for monitoring and treating patients with heart failure (HF) are discussed. The system may sense cardiac signals, and receives information about patient physiological or functional conditions. A stimulation parameter table that includes recommended values of atrioventricular delay (AVD) or other timing parameters maybe created at a multitude of patient physiological or functional conditions. The system may periodically reassess patient physiological or functional conditions. A therapy programmer circuit may dynamically switch between left ventricular-only pacing and biventricular pacing, or switch between single site pacing and multisite pacing based on the patient condition. The therapy programmer circuit may adjust AVD and other timing parameters using the cardiac signal input and the stored stimulation parameter table. A HF therapy may be delivered according to the determined stimulation site, stimulation mode, and the stimulation timing.

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.

A device includes a handle, an expandable structure including a plurality of splines extending from a proximal hub to a distal hub, a first electrode on a first spline of the plurality of splines, an outer tube extending from the handle to the proximal hub, and a shaft extending through the outer tube from the handle to the distal hub. The expandable structure has a collapsed state and a self-expanded state. The handle is configured to retract the shaft. Retracting the shaft may expand the expandable structure outward of the self-expanded state.

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.

Systems and methods for assessing hemodynamic status of a patient experiencing atrial tachyarrhythmia such as an atrial fibrillation (AF) episode are disclosed. A system can comprise an atrial tachyarrhythmia detection circuit configured to detect an AF episode, a hemodynamic sensor circuit configured to sense at least one hemodynamic signal, and a hemodynamic status analyzer circuit that can calculate one or more signal metrics using the sensed hemodynamic signal during the AF episode. The hemodynamic status analyzer circuit can categorize the hemodynamic status of the patient into one of two or more categorical hemodynamic status levels which indicate elevated hemodynamic impact of the detected AF episode. A user interface can provide to an end-user a presentation of the categorized hemodynamic status level during AF.

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.

Hemodynamic performance of a heart may be improved by determining, from a location associated with a diaphragm, an occurrence of a valid cardiac event; and then delivering asymptomatic electrical stimulation therapy directly to the diaphragm at termination of a diaphragmatic stimulation delay period that is timed relative to the occurrence of the valid cardiac event. The diaphragmatic stimulation delay period may be automatically established by sensing a plurality of cardiac events directly from a diaphragm; and for each of the sensed cardia events, determining whether the sensed cardiac event represents a valid cardiac event or a non-valid cardiac event. The diaphragmatic stimulation delay period is then calculated based on a plurality of sensed cardia events that are determined to be valid.