Abstract: Implantable medical systems enter an exposure mode of operation, either manually via a down linked programming instruction or by automatic detection by the implantable system of exposure to a magnetic disturbance. A controller then determines the appropriate exposure mode by considering various pieces of information including the device type including whether the device has defibrillation capability, pre-exposure mode of therapy including which chambers have been paced, and pre-exposure cardiac activity that is either intrinsic or paced rates. Additional considerations may include determining whether a sensed rate during the exposure mode is physiologic or artificially produced by the magnetic disturbance. When the sensed rate is physiologic, then the controller uses the sensed rate to trigger pacing and otherwise uses asynchronous pacing at a fixed rate.

Abstract: A medical device includes a motion sensor configured to sense a motion signal. The medical device includes a control circuit configured to determine at least one ventricular event metric from the motion signal sensed over multiple of atrial cycles, determine that the ventricular event metric meets atrioventricular block criteria and generate an output in response to determining the atrioventricular block.

Abstract: Patient activity or inactivity may be determined based, at least in part, on a movement signal representative, or indicative, of movement of a patient. When the patient is determined to be inactive based the movement signal monitored over a moving time window, cardiac remodeling pacing may be delivered to the patient.

Abstract: A ventricular pacemaker is configured to determine a ventricular rate interval by determining at least one ventricular event interval between two consecutive ventricular events and determine a rate smoothing ventricular pacing interval based on the ventricular rate interval. The pacemaker is further configured to detect an atrial event from a sensor signal and deliver a ventricular pacing pulse in response to detecting the atrial event from the sensor signal. The pacemaker may start the rate smoothing ventricular pacing interval to schedule a next pacing pulse to be delivered upon expiration of the rate smoothing ventricular pacing interval.

Abstract: An implantable medical device includes an activity sensor, a pulse generator, and a control module. The control module is configured to determine activity metrics from the activity signal and determine an activity metric value at a predetermined percentile of the activity metrics. The control module sets a lower pacing rate set point based on the activity metric value at the predetermined percentile.

Abstract: 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.

Abstract: A medical device is configured to sense a cardiac electrical signal and determine from the cardiac electrical signal at least one of a maximum peak amplitude of a positive slope of the cardiac electrical signal and a maximum peak time interval from a pacing pulse to the maximum peak amplitude. The device is configured to determine a capture type of the pacing pulse based on at least one or both of the maximum peak amplitude and the maximum peak time interval.

Abstract: A medical device is configured to identify a first group of cardiac events, determine a cardiac event interval based on the first group of cardiac events and determine whether the cardiac event interval is less than a threshold interval or greater than the threshold interval. The medical device is configured to select a first blanking period duration if the cardiac event interval is less than the threshold interval or a second blanking period duration if the cardiac event interval is greater than the threshold interval.

Abstract: An implantable medical device system receives a cardiac electrical signal produced by a patient's heart and comprising atrial P-waves and delivers a His bundle pacing pulse to the patient's heart via a His pacing electrode vector. The system determines a timing of a sensed atrial P-wave relative to the His bundle pacing pulse and determines a type of capture of the His bundle pacing pulse in response to the determined timing of the atrial P-wave.

Abstract: Implantable medical devices automatically switch from a normal mode of operation to an exposure mode of operation and back to the normal mode of operation. The implantable medical devices may utilize hysteresis timers in order to determine if entry and/or exit criteria for the exposure mode are met. The implantable medical devices may utilize additional considerations for entry to the exposure mode such as a confirmation counter or a moving buffer of sensor values. The implantable medical devices may utilize additional considerations for exiting the exposure mode of operation and returning to the normal mode, such as total time in the exposure mode, patient position, and high voltage source charge time in the case of devices with defibrillation capabilities.

Abstract: A ventricular pacemaker is configured to determine a ventricular rate interval by determining at least one ventricular event interval between two consecutive ventricular events and determine a rate smoothing ventricular pacing interval based on the ventricular rate interval. The pacemaker is further configured to detect an atrial event from a sensor signal and deliver a ventricular pacing pulse in response to detecting the atrial event from the sensor signal. The pacemaker may start the rate smoothing ventricular pacing interval to schedule a next pacing pulse to be delivered upon expiration of the rate smoothing ventricular pacing interval.

Abstract: A medical device is configured to sense a cardiac electrical signal and determine from the cardiac electrical signal at least one of a maximum peak amplitude of a positive slope of the cardiac electrical signal and a maximum peak time interval from a pacing pulse to the maximum peak amplitude. The device is configured to determine a capture type of the pacing pulse based on at least one or both of the maximum peak amplitude and the maximum peak time interval.

Abstract: A computing device may be communicably coupled to a first pacemaker implanted in a heart of a patient and a second pacemaker implanted in the heart of the patient. The computing device may receive, from the first pacemaker, first race responsive pacing data, and may receive, from the second pacemaker, second rate responsive pacing data. The computing device may synchronize, based at least in part on the first rate responsive pacing data and the second rate responsive pacing data, rate responsive pacing of the first pacemaker and the second pacemaker.

Abstract: An implantable medical device is configured determine a numerical value of a variable that is monitored by the implantable medical device and convert the numerical value to a data sequence of modulated electrical stimulation rate intervals. The implantable medical device delivers electrical stimulation pulses according to the data sequence of modulated stimulation rate intervals to cause a modulated rate of activation of excitable tissue of a patient corresponding to the modulated stimulation rate intervals. The modulated rate of activation is detectable by a rate monitor for demodulation to the numerical value of the monitored variable data value. In some examples, the implantable medical device is a pacemaker delivering cardiac pacing pulses according to modulated pacing rate intervals to cause a modulated heart rate of the patient detectable by a heart rate monitor for demodulation to the numerical value of the monitored variable.

Abstract: An implantable medical device system receives a cardiac electrical signal produced by a patient's heart and comprising atrial P-waves and delivers a His bundle pacing pulse to the patient's heart via a His pacing electrode vector. The system determines a timing of a sensed atrial P-wave relative to the His bundle pacing pulse and determines a type of capture of the His bundle pacing pulse in response to the determined timing of the atrial P-wave.

Abstract: A medical having a motion sensor is configured to set an atrial event sensing parameter used for sensing atrial event signals from a motion signal produced by the motion sensor. The medical device sets an atrial event sensing parameter by applying a sensing window during each one of multiple ventricular cycles, determining a feature of the motion signal during the sensing window for at least a portion of the ventricular cycles, and setting the atrial event sensing parameter based on the determined features. The medical device may sense the atrial event from the motion signal according to the atrial event sensing parameter.

Abstract: A system comprises an implantable medical device configured to generate temperature data and impedance data associated with temperature and impedance of a patient proximate to the implantable medical device. The system further comprises processing circuitry configured to determine whether a first one or more infection criteria are satisfied by temperature data and impedance data generated by the implantable medical device during a first time interval, wherein the first one or more infection criteria include at least one criterion indicative of decreased impedance, determine whether a second one or more infection criteria are satisfied by the temperature data and impedance data generated by the implantable medical device during a second time interval subsequent to the first time interval, wherein the second one or more infection criteria include at least one criterion indicative of increased impedance, and output, based on satisfaction of the first and second infection criteria, an indication of infection.

Abstract: A medical device includes a motion sensor for producing a motion signal including cardiac event signals. The medical device generates a ventricular pacing pulse upon expiration of a pacing interval. The medical device determines a synchrony metric from the motion signal after a delivered ventricular pacing pulse and adjusts the pacing interval based on the synchrony metric.

Abstract: The control module of a first pacemaker included in an implantable medical device system including the first pacemaker and a second pacemaker is configured to set a pacing escape interval in response to a far field pacing pulse sensed by the first pacemaker. The far field pacing pulse is a pacing pulse delivered by the second pacemaker. The pacing escape interval is allowed to continue without restarting the in response to a far field intrinsic event sensed by the first pacemaker during the pacing escape interval. The first pacemaker delivers a cardiac pacing pulse to the heart upon expiration of the pacing escape interval.

Abstract: An implantable medical device is configured determine a numerical value of a variable that is monitored by the implantable medical device and convert the numerical value to a data sequence of modulated electrical stimulation rate intervals. The implantable medical device delivers electrical stimulation pulses according to the data sequence of modulated stimulation rate intervals to cause a modulated rate of activation of excitable tissue of a patient corresponding to the modulated stimulation rate intervals. The modulated rate of activation is detectable by a rate monitor for demodulation to the numerical value of the monitored variable data value. In some examples, the implantable medical device is a pacemaker delivering cardiac pacing pulses according to modulated pacing rate intervals to cause a modulated heart rate of the patient detectable by a heart rate monitor for demodulation to the numerical value of the monitored variable.