Devices, systems and methods provide forms of asymptomatic diaphragmatic stimulation (ADS) therapy that affect pressures within the intrathoracic cavity, including: 1) dual-pulse ADS therapy, during which a first ADS pulse is delivered during a diastolic phase of a cardiac cycle and a second ADS pulse is delivered during a systolic phase, 2) paired-pulse ADS therapy, during which a first ADS pulse is delivered, closely followed by a second ADS pulse, with the second ADS pulse functioning to extend or enhance a phase of a transient, partial contraction of the diaphragm, and 3) multiple-pulse ADS therapy, during which a stream of ADS pulses is delivered, wherein the time between pulses is based on heart rate. Devices, systems and methods also monitor electromyography (EMG) activity of the diaphragm relative to baseline activity to assess the health of a diaphragm subject to ADS therapy and to adjust ADS therapy parameters or sensing parameters.

Techniques for obtaining impedance data to provide an early warning for heart failure decompensation are described. An example device may be configured to measure subcutaneous impedance values, and increment an impedance score. In some examples, the device may use an adaptive threshold and fluid index in incrementing the impedance score. In some examples, the impedance score is compared to a threshold to determine a heart failure status of a patient.

Techniques for determining a likeliness that a patient may incur an adverse health event are described. An example technique may include utilizing a probability model that uses as evidence nodes various diagnostic states of physiological parameters, which may include one or more subcutaneous impedance parameters. The probability model may include a Bayesian Network that determines a posterior probability of the adverse health event occurring within a predetermined period of time.

An implantable medical device and computer implemented methods comprise a sensing circuit configured to sense cardiac activity (CA) signals. An accelerometer is configured to be implanted in a patient and obtain accelerometer data along at least one axis. A memory is configured to store program instructions and device parameters associated with each ventricular arrhythmia (VA) therapy in a collection of VA therapies with different levels of intensity. One or more processors execute the program instructions and are configured to analyze the CA signals over one or more cardiac beats, determine a VA episode based on the analysis of the CA signals, determine a posture of the patient based on the accelerometer data in response to the determination of the VA episode, and select a first VA therapy from the collection of VA therapies based on the posture.

The disclosure is directed towards posture-responsive therapy. To avoid interruptions in effective therapy, an implantable medical device may include a posture state module that detects the posture state of the patient and automatically adjusts therapy parameter values according to the detected posture state. A system may include a memory that stores posture state definitions, a posture state module that records a plurality of postures of a patient over a period of time, and a processor that identifies a set of the plurality of postures that fall within a posture state, and redefines a boundary of the posture state based on where the postures fall within the posture state.

An intracardiac ventricular pacemaker is configured to operate in in a selected one of an atrial-tracking ventricular pacing mode and a non-atrial tracking ventricular pacing mode. A control circuit of the pacemaker determines at least one motion signal metric from the motion signal, compares the at least one motion signal metric to pacing mode switching criteria, and, responsive to the pacing mode switching criteria being satisfied, switches from the selected one of the non-atrial tracking pacing mode and the atrial tracking pacing mode to the other one of the non-atrial tracking pacing mode and the atrial tracking pacing mode for controlling ventricular pacing pulses delivered by the pacemaker.

A biventricular (BiV) implantable cardiac stimulator contains a stimulation control unit, one or more stimulation units, an impedance measurement unit and an impedance evaluation unit. The stimulation control unit is operatively connected to one or more stimulation units to control delivery of stimulation pulses by the one or more stimulation units. The stimulation control unit is configured to assess ventricular contractility based on an impedance signal generated by the impedance evaluation unit and to switch between at least a univentricular left ventricular stimulation mode and a biventricular stimulation mode and to evaluate the ventricular contractility in relation to the respective ventricular stimulation mode.

A leadless pacemaker device for providing an intra-cardiac pacing includes processing circuitry configured to generate ventricular pacing signals for stimulating ventricular activity at a ventricular pacing rate, a first sensor configuration receiving a first sense signal, and a second sensor configuration receiving a second sense signal. The processing circuitry derives, in a first sensing state, atrial events from the first sense signal for controlling the ventricular pacing rate based on the atrial events. The processing circuitry switches, based on at least one switching criterion, from the first sensing state to a second sensing state in which the processing circuitry derives atrial events from the second sense signal. The second sense signal is received by the second sensor configuration for detection of atrial events and the second sensor configuration is a motion sensor or a sound sensor. A method for operating the pacemaker device is also provided.

Embodiments described herein generally relate to methods and systems for monitoring and responding to changes in a patient's physiologic status. A method includes sensing pulmonary arterial pressure (PAP) and thoracic impedance of a patient at rest. The method also includes detecting, based on the sensed PAP, whenever the patient's PAP at rest is outside an acceptable range of PAP measures for the patient at rest, and detecting, based on the sensed thoracic impedance, whenever the patient's respiration at rest is outside an acceptable range of respiration measures for the patient at rest. Various different actions are triggered depending upon whether the patient's PAP at rest is outside the acceptable range of PAP measures for the patient at rest, and whether the patient's respiration at rest is within the acceptable range of respiration measures for the patient at rest. Other embodiments relate to similar methods performed at other levels of exertion.

A method includes determining whether electrical activity is indicative of atrial fibrillation, determining whether mechanical activity is indicative of atrial fibrillation, and adjusting a pacing parameter or mode based on whether the electrical activity and the mechanical activity are indicative of atrial fibrillation. The electrical activity may be detected based on a far-field measurement. The method may be performed using a leadless implantable medical device.