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 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.

Abstract: A medical device includes a motion sensor configured to produce a motion signal and a control circuit configured to sense atrial events from the motion signal. In some examples, the control circuit is configured to set a ventricular diastolic event window and set a threshold amplitude during the ventricular diastolic event window for sensing an atrial event in response to the motion signal crossing the threshold amplitude during the ventricular diastolic window. The control circuit may determine a maximum amplitude of the motion signal during the ventricular diastolic event window for multiple ventricular cycles and determine an amplitude metric based on at least a portion of the determined maximum amplitudes. The control circuit may determine a target value of the threshold amplitude based on at least the amplitude metric and adjust the threshold amplitude toward the target value.

Abstract: 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.

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: 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.

Abstract: An implantable medical device system is configured to detect a tachyarrhythmia from a cardiac electrical signal and start an ATP therapy delay period. The implantable medical device determines whether the cardiac electrical signal received during the ATP therapy delay period satisfies ATP delivery criteria. A therapy delivery module is controlled to cancel the delayed ATP therapy if the ATP delivery criteria are not met and deliver the delayed ATP therapy if the ATP delivery criteria are met.

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: 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 implantable medical device system is configured to detect a tachyarrhythmia from a cardiac electrical signal and start an ATP therapy delay period. The implantable medical device determines whether the cardiac electrical signal received during the ATP therapy delay period satisfies ATP delivery criteria. A therapy delivery module is controlled to cancel the delayed ATP therapy if the ATP delivery criteria are not met and deliver the delayed ATP therapy if the ATP delivery criteria are met.

Abstract: An implantable medical device system is configured to sense cardiac events in response to a cardiac electrical signal crossing a cardiac event sensing threshold. A control circuit is configured to determine a drop time interval based on a heart rate and control a sensing circuit to hold the cardiac event sensing threshold at a threshold value during the drop time interval.

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: An implantable medical device system is configured to sense cardiac events in response to a cardiac electrical signal crossing a cardiac event sensing threshold. A control circuit is configured to determine a drop time interval based on a heart rate and control a sensing circuit to hold the cardiac event sensing threshold at a threshold value during the drop time interval.

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: An implantable medical device system capable of sensing cardiac electrical signals includes a sensing circuit, a therapy delivery circuit and a control circuit. The sensing circuit is configured to receive a cardiac electrical signal and sense a cardiac event in response to the signal crossing a cardiac event sensing threshold. The therapy delivery circuit is configured to deliver an electrical stimulation therapy to a patient's heart via the electrodes coupled to the implantable medical device. The control circuit is configured to control the sensing circuit to set a starting value of the cardiac event sensing threshold and hold the starting value constant for a sense delay interval. The control circuit is further configured to detect an arrhythmia based on cardiac events sensed by the sensing circuit and control the therapy delivery circuit to deliver the electrical stimulation therapy in response to detecting the arrhythmia.

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: An implantable medical device system capable of sensing cardiac electrical signals includes a sensing circuit, a therapy delivery circuit and a control circuit. The sensing circuit is configured to receive a cardiac electrical signal and sense a cardiac event in response to the signal crossing a cardiac event sensing threshold. The therapy delivery circuit is configured to deliver an electrical stimulation therapy to a patient's heart via the electrodes coupled to the implantable medical device. The control circuit is configured to control the sensing circuit to set a starting value of the cardiac event sensing threshold and hold the starting value constant for a sense delay interval. The control circuit is further configured to detect an arrhythmia based on cardiac events sensed by the sensing circuit and control the therapy delivery circuit to deliver the electrical stimulation therapy in response to detecting the arrhythmia.

Abstract: In some examples, controlling delivery of therapy includes using an implantable medical device comprising at least one electrode. Processing circuitry of a system comprising the device may receive, from an application running on a patient personal device, a patient request entered by the patient into the application. The processing circuitry may further determine, based on the patient request, a requested value of a therapy parameter, compare the requested value to information stored in a memory of the medical device system, the information indicating one or more allowable values of the therapy parameter, determine that the requested value is one of the allowable values based on the comparison of the requested value of the therapy parameter to the one or more allowable values, and control the implantable medical device to deliver cardiac pacing via the at least one electrode according to the requested value for a period of time.