A medical device and method conserve electrical power used in monitoring cardiac arrhythmias. The device includes a sensing circuit configured to sense a cardiac signal, a power source and a control circuit having a processor powered by the power source. The control circuit is configured to operate in a normal state by waking up the processor to analyze the cardiac electrical signal for determining a state of an arrhythmia. The control circuit switches from the normal state to a power saving state that includes waking up the processor at a lower rate than during the normal state.

A system for application of neurostimulation includes an outer sheath, an elongate inner member in the outer sheath and movable relative to the outer sheath. The inner lumen has a distal end. An expandable member is coupled to the distal end of the inner member and is in the outer sheath. The expandable member is self-expanding upon from a compressed state in the outer sheath to an expanded state out of the outer sheath. The expandable member includes a distal portion including a plurality of wires woven together and a proximal portion including the plurality of wires extending parallel to a longitudinal axis. The system includes a plurality of electrode assemblies outward of the expandable member and circumferentially spaced around the expandable member. Each electrode assembly is coupled to two of the wires extending parallel to the longitudinal axis. Each electrode assembly includes a plurality of longitudinally-spaced electrodes.

According to some aspects, a cardiac pacemaker for implantation within a subject is provided, the pacemaker including a housing, at least one sensor configured to detect an activity level of the subject, and at least one processor coupled to the sensor configured to detect inactivity of the subject based on output from the at least one sensor, produce a first signal configured to increase the heart rate of the subject to a first heart rate during a first time period, wherein the first heart rate is above a resting heart rate and below 100 beats per minute, and in response to determining that the first time period has elapsed, producing a second signal configured to increase the heart rate of the subject to a second heart rate during a second time period, wherein the second heart rate is between 100 and 140 beats per minute.

A pacemaker is configured to operate in an atrial synchronous ventricular pacing mode and, after expiration of a conduction check time interval, switch to an asynchronous ventricular pacing mode that includes setting a ventricular pacing interval to a base pacing rate interval. The pacemaker is further configured to determine when atrioventricular block detection criteria are satisfied during the asynchronous ventricular pacing mode and, responsive to the atrioventricular block detection criteria being satisfied, switch back to the atrial synchronous ventricular pacing mode.

A wearable cardioverter defibrillator (WCD) system includes a support structure having an adjustable fastening assembly to fasten portions of the support structure together to fit the support structure on a patient. The adjustable fastening assembly enables the patient wearing the support structure to adjust the fit of the support structure without unfastening the portions from each other. The adjustable fastening assembly may also enable the patient to adjust the fit of the support structure while wearing clothing over the support structure and without having to adjust the clothing to view or access the adjustable fastening assembly.

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 Medical Device Application (MDA) is disclosed for an external device (e.g., a cell phone) that can communicate with an Implantable Medical Device (IMD). The MDA receives data logged in the IMD, processes that data in manners reviewable by an IMD patient, and that can control the IMD based on such processed data. The MDA can use the logged data to adjust IMD therapy based on patient activity or posture, and allows a patient to learn optimal therapy settings for particular activities. The MDA can also use the logged data to allow a patient to review details about IMD battery performance, whether such battery is primary or rechargeable, and to control stimulation parameters based on that performance. The MDA also allows a patient to enter medicine dose information, to review the relationship between medicinal therapy and IMD therapy, and to adjust IMD therapy based on the dosing information.

Techniques related to classifying a posture state of a living body are disclosed. One aspect relates to sensing at least one signal indicative of a posture state of a living body. Posture state detection logic classifies the living body as being in a posture state based on the at least one signal, wherein this classification may take into account at least one of posture and activity state of the living body. The posture state detection logic further determines whether the living body is classified in the posture state for at least a predetermined period of time. Response logic is described that initiates a response as a result of the body being classified in the posture state only after the living body has maintained the classified posture state for at least the predetermined period of time. This response may involve a change in therapy, such as neurostimulation therapy, that is delivered to the living body.

A medical device is configured to sense a cardiac signal that includes far field ventricular event signals and determine a ventricular activity metric from the sensed cardiac signal. The ventricular activity metric may be representative of a ventricular rate or an atrioventricular time interval. The medical device is configured to determine an atrioventricular synchrony metric based on the ventricular activity metric and generate an output based on the atrioventricular synchrony metric. The device may include a memory configured to store data corresponding to the atrioventricular synchrony metric.

An implantable medical device system delivers a pacing pulse to a patient's heart and starts a first pacing interval corresponding to a pacing rate in response to the delivered pacing pulse. The system charges a holding capacitor to a pacing voltage amplitude during the first pacing interval. The system detects an increased intrinsic heart rate that is at least a threshold rate faster than the current pacing rate from a cardiac electrical signal received by a sensing circuit of the implantable medical device. The system starts a second pacing interval in response to an intrinsic cardiac event sensed from the cardiac electrical signal and withholds charging of the holding capacitor for at least a portion of the second pacing interval in response to detecting the increased intrinsic heart rate.