Abstract: An implantable medical device having a housing that encloses a pulse generator and a sensing module includes a housing-based cathode electrode electrically coupled to the pulse generator and to the sensing module. A sensing extension extending from the housing proximal end includes an anode electrode electrically coupled to the sensing module for sensing cardiac electrical signals. The sensing extension includes a flotation member that causes the sensing extension to extend away from the housing along a direction of flowing blood when the implantable medical device is deployed within a cardiovascular system of a patient.

Abstract: An intracardiac pacemaker system is configured to produce physiological atrial event signals by a sensing circuit of a ventricular intracardiac pacemaker and select a first atrial event input as the physiological atrial event signals. The ventricular intracardiac pacemaker detects atrial events from the selected first atrial event input, determines if input switching criteria are met, and switches from the first atrial event input to a second atrial event input in response to the input switching criteria being met. The second atrial event input includes broadcast atrial event signals produced by a second implantable medical device and received by the ventricular intracardiac pacemaker.

Abstract: An intracardiac ventricular pacemaker having a motion sensor is configured to produce a motion signal including an atrial systolic event and at least one ventricular diastolic event. The pacemaker is configured to set an atrial refractory period, detect a change in a ventricular diastolic event metric and adjust the atrial refractory period in response to detecting the change. The pacemaker sets set an atrioventricular pacing interval in response to detecting the atrial systolic event from the motion signal after expiration of the atrial refractory period.

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: 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: An intracardiac pacemaker system is configured to produce physiological atrial event signals by a sensing circuit of a ventricular intracardiac pacemaker and select a first atrial event input as the physiological atrial event signals. The ventricular intracardiac pacemaker detects atrial events from the selected first atrial event input, determines if input switching criteria are met, and switches from the first atrial event input to a second atrial event input in response to the input switching criteria being met. The second atrial event input includes broadcast atrial event signals produced by a second implantable medical device and received by the ventricular intracardiac pacemaker.

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: An intracardiac ventricular pacemaker having a motion sensor is configured to produce a motion signal including an atrial systolic event and at least one ventricular diastolic event. The pacemaker is configured to set an atrial refractory period, detect a change in a ventricular diastolic event metric and adjust the atrial refractory period in response to detecting the change. The pacemaker sets set an atrioventricular pacing interval in response to detecting the atrial systolic event from the motion signal after expiration of the atrial refractory period.

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: 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: 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 implantable medical device having a housing that encloses a pulse generator and a sensing module includes a housing-based cathode electrode electrically coupled to the pulse generator and to the sensing module. A sensing extension extending from the housing proximal end includes an anode electrode electrically coupled to the sensing module for sensing cardiac electrical signals. The sensing extension includes a flotation member that causes the sensing extension to extend away from the housing along a direction of flowing blood when the implantable medical device is deployed within a cardiovascular system of a patient.

Abstract: An implantable medical device and associated method detect obstructed inspiration by monitoring an blood pressure signal. A respiration signal is monitored and a phase of respiratory inspiration is detected from the respiration signal. A trend in the pressure signal is measured during the inspiration phase. Obstructed inspiration for the inspiration phase is detected in response to the measured the trend.

Abstract: A method includes controlling a cardiac pacing rate of an implantable medical device to control a heart rate of a patient and detecting inhalation and exhalation of the patient. The method further includes determining that the patient is in a resting state, and, in response to determining that the patient is in the resting state, incrementally increasing the pacing rate while exhalation of the patient is detected and incrementally decreasing the pacing rate while inhalation of the patient is detected.

Abstract: A method includes controlling a cardiac pacing rate of an implantable medical device (IMD) to control a heart rate of a patient and determining that the patient is in a resting state. The method further includes modifying the pacing rate of the IMD for N cardiac cycles in response to determining that the patient is in the resting state. N is an integer greater than 1. Modifying the pacing rate includes incrementally increasing the pacing rate for a first portion of the N cardiac cycles, and incrementally decreasing the pacing rate for a second portion of the N cardiac cycles.

Abstract: A method of determining a respiration parameter in a medical device in which pressure signals are sensed to generate corresponding sample points, and a breath detection threshold is continuously adjusted in response to the generated sample points to generate a current adjusted breath detection threshold. A current generated sample point is compared to the current adjusted breath detection threshold, and the continuous adjusting of the breath detection threshold is suspended and the breath detection threshold is equal to the most current adjusted breath detection threshold generated prior to the suspending in response to the comparing. A next sample point, generated subsequent to the suspending, is compared to the set breath detection threshold, and the respiration parameter is determined in response to the comparing of a next sample point to the set breath detection threshold.

Abstract: A method includes controlling a cardiac pacing rate of an implantable medical device to control a heart rate of a patient and detecting inhalation and exhalation of the patient. The method further includes determining that the patient is in a resting state, and, in response to determining that the patient is in the resting state, incrementally increasing the pacing rate while exhalation of the patient is detected and incrementally decreasing the pacing rate while inhalation of the patient is detected.

Abstract: A method includes controlling a cardiac pacing rate of an implantable medical device (IMD) to control a heart rate of a patient and determining that the patient is in a resting state. The method further includes modifying the pacing rate of the IMD for N cardiac cycles in response to determining that the patient is in the resting state. N is an integer greater than 1. Modifying the pacing rate includes incrementally increasing the pacing rate for a first portion of the N cardiac cycles, and incrementally decreasing the pacing rate for a second portion of the N cardiac cycles.

Abstract: A medical device for determining a respiratory effort having a pressure sensor to sense pressure signals, a housing having system components positioned therein, and a microprocessor positioned within the housing, wherein the microprocessor detects an inspiration and an expiration in response to the pressure signals, detects a breath in response to the detected inspiration and the detected expiration, and determines the respiratory effort in response to the detected breath.

Abstract: A method of determining respiratory effort in a medical device in which pressure signals are sensed to generate corresponding sample points, an inspiration and an expiration are detected in response to the sensed pressure signals, a breath is detected in response to the detected inspiration and the detected expiration, and the respiratory effort is determined in response to the detected breath.