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.

An apparatus comprises a respiration sensing circuit configured for coupling electrically to a plurality of electrodes and for sensing a respiration signal representative of respiration of a subject; a signal processing circuit electrically coupled to the respiration sensing circuit and configured to extract a respiration parameter from a sensed respiration signal and determine a signal performance metric for the sensed respiration signal using the respiration parameter; and a control circuit. The control circuit is configured to: initiate sensing of a plurality of respiration signals using different electrode combinations of the plurality of electrodes and determining of the signal performance metric for the sensed respiration signals; and enable an electrode combination from the plurality of electrodes and for use in monitoring respiration of the subject according to the signal performance metric.

Systems and methods for calibrating an orientation of an implantable device in a patient is described. An exemplary system includes a calibration circuit that can receive acceleration information sensed from an implantable medical device (IMD) implanted in a patient, and receive reference acceleration information sensed from a reference device associated with the patient. The acceleration information and the reference acceleration information are acquired when the patient assumes a first posture or in a first position. The calibration circuit determines a spatial relationship between an orientation of the IMD and a reference orientation of the reference device using the received acceleration information and the received reference acceleration information, and calibrate subsequent acceleration information sensed from the IMD using the determined spatial relationship to correct for the orientation of the IMD.

A cardiac defibrillation system that includes a pulse generator to generate therapeutic electrical pulses and at least one lead inserted through an intercostal space in the region of a cardiac notch of the left lung of a patient, the lead having a distal end configured to transmit the therapeutic electrical pulses generated by the pulse generator to defibrillate the heart of the patient.

Implantable medical devices such as leadless cardiac pacemakers may be configured to communicate using more than one mode of communication. For example, in some cases, an implantable medical device may be configured to communicate via conducted communication in some circumstances and to communicate via inductive communication in other circumstances. In some cases, the implantable medical device may be configured to switch between communication modes in order to improve communication.

A leadless cardiac pacemaker (LCP) is configured to sense cardiac activity and to pace a patient's heart and is disposable within a ventricle of the patient's heart. The LCP MAY include a housing, a first electrode and a second electrode that are secured relative to the housing and are spaced apart. A controller is disposed within the housing and is operably coupled to the first electrode and the second electrode such that the controller is capable of receiving, via the first electrode and the second electrode, electrical cardiac signals of the heart. The LCP may include a pressure sensor and/or an accelerometer. The controller may determine a pace time within a cardiac cycle based at least in part upon an indication of metabolic demand.

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.