Abstract: A medical device is configured to determine a rate smoothing pacing interval based on at a ventricular cycle length ending with a ventricular pacing pulse and determine a post-sense ventricular pacing interval based on a ventricular cycle length ending with a sensed ventricular event signal. The medical device may be configured to start a ventricular pacing interval set to the post-sense ventricular pacing interval in response to the sensed ventricular event signal and generate a ventricular pacing pulse in response to the expiration of the post-sense ventricular pacing interval.

Abstract: 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.

Abstract: An implantable medical device system includes an extracardiac sensing device and an intracardiac pacemaker. The sensing device senses a P-wave attendant to an atrial depolarization of the heart via housing-based electrodes carried by the sensing device when the sensing device is implanted outside the cardiovascular system and sends a trigger signal to the intracardiac pacemaker in response to sensing the P-wave. The intracardiac pacemaker detects the trigger signal and schedules a ventricular pacing pulse in response to the detected trigger signal.

Abstract: A system includes an implantable medical device (IMD) and processing circuitry. The IMD includes sensing circuitry configured to sense cardiac electrical signals of a patient, and therapy delivery circuitry configured to deliver demand cardiac pacing to a heart of the patient based on the cardiac electrical signals. The processing circuitry is configured to: determine, for each of a plurality of time units, based on the cardiac electrical signals and the delivery of demand cardiac pacing during the time units, a plurality of metrics indicative of a need for continued delivery of demand cardiac pacing to the heart of the patient. The plurality of metrics includes a metric associated with a duration of one or more pacing episodes during the time unit. The processing circuitry is further configured to generate a graphical representation of the plurality of metrics of the plurality of time units for presentation to a user.

Abstract: An intracardiac ventricular pacemaker having a motion sensor is configured to produce a motion signal including an atrial systolic event and a ventricular diastolic event indicating a passive ventricular filling phase, set a detection threshold to a first amplitude during an expected time interval of the ventricular diastolic event and to a second amplitude lower than the first amplitude after an expected time interval of the ventricular diastolic event. The pacemaker is configured to detect the atrial systolic event in response to the motion signal crossing the detection threshold and set an atrioventricular pacing interval in response to detecting the atrial systolic event.

Abstract: A medical device is configured to sense a cardiac electrical signal and detect an atrial tachyarrhythmia based on the sensed cardiac electrical signal. The medical device is configured to determine that far field oversensing criteria are met by the cardiac electrical signal during the detected atrial tachyarrhythmia. The medical device may detect termination of the detected atrial tachyarrhythmia in response to the far field oversensing criteria being met.

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 system includes an extracardiac sensing device and an intracardiac pacemaker. The sensing device senses a P-wave attendant to an atrial depolarization of the heart via housing-based electrodes carried by the sensing device when the sensing device is implanted outside the cardiovascular system and sends a trigger signal to the intracardiac pacemaker in response to sensing the P-wave. The intracardiac pacemaker detects the trigger signal and schedules a ventricular pacing pulse in response to the detected trigger signal.

Abstract: An intracardiac ventricular pacemaker having a motion sensor is configured to produce a motion signal including an atrial systolic event and a ventricular diastolic event indicating a passive ventricular filling phase, set a detection threshold to a first amplitude during an expected time interval of the ventricular diastolic event and to a second amplitude lower than the first amplitude after an expected time interval of the ventricular diastolic event. The pacemaker is configured to detect the atrial systolic event in response to the motion signal crossing the detection threshold and set an atrioventricular pacing interval in response to detecting the atrial systolic event.

Abstract: 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.

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: 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.

Abstract: 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.

Abstract: A medical device is configured to produce a cardiac motion signal by sampling a signal produced by an axis of a motion sensor, starting a blanking period, suspending the sampling of the signal during at least a portion of the blanking period, and restarting the sampling of the signal at the sampling frequency before the blanking period has expired. The medical device may detect a cardiac event from the cardiac motion signal and generate a pacing pulse in response to detecting the cardiac event in some examples.

Abstract: A medical device is configured to receive a cardiac signal and determine a morphology matching score from the cardiac signal and a capture detection morphology template that corresponds to a first type of cardiac pacing capture that includes capture of at least a first portion of the His-Purkinje system. The device is configured to detect a second type of cardiac pacing capture in response to the morphology matching score being less than the first match threshold. The second type of cardiac pacing capture is different than the first type of cardiac pacing capture and may include capture of the ventricular myocardium and/or a second portion of the His-Purkinje system different than the first portion.

Abstract: A medical device is configured to generate an acceleration signal and a temperature signal. The device is configured to determine an activity metric from the acceleration signal that is representative of patient physical activity. In response to determining that the activity metric is equal to or greater than a previously determined activity metric, the device is configured to adjust a target cardiac pacing rate based at least on a temperature change determined from the temperature signal. The device may include a pulse generator for generating cardiac pacing pulses based on the target cardiac pacing rate.

Abstract: This disclosure is directed to devices and techniques for classifying of pacing captures to evaluate effectiveness of pacing by a pacing device, such as an implantable medical device (IMD). An example system includes stimulation circuitry to generate a pacing stimulus, sensing circuitry to sense an evoked response after the pacing stimulus, and processing circuitry. The processing circuitry determines classification features from the evoked response and applies the classification features to a classification model, the classification model generated by a machine learning algorithm using one or more test sets comprising a plurality of sample evoked responses for each of a plurality of classifications. Based on the output of the model, the processing circuitry classifies the evoke response as one of the plurality of classifications.

Abstract: A medical device is configured to sense a cardiac signal, determine a monitoring metric representative of activity of at least one heart chamber from the sensed cardiac signal, and determine that the monitoring metric meets expected rhythm criteria. The medical device may enable a monitoring feature of the medical device that is based on processing and analysis of the cardiac signal in response to the monitoring metric meeting the expected rhythm criteria.

Abstract: 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.