Systems and methods are provided for detecting arrhythmias in cardiac activity is provided. The systems and methods include measuring conduction delays between an atria (A) and multiple left ventricular (LV) electrodes to obtain multiple intrinsic A/LV intervals, measuring conduction delays between a right ventricular (RV) and the multiple LV electrodes to obtain multiple intrinsic VV intervals. The systems and methods include calculating a first atrial ventricular (AV) delay based on at least one of the intrinsic A/LV intervals, and calculating a second AV delay based on at least one of the intrinsic VV intervals. The systems and methods include selecting a biventricular (BiV) pacing mode or an LV only pacing mode based on a relation between the first and second AV delays, and delivering a pacing therapy based on the selecting operation.

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.

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.

An implantable cardiac rhythm management medical device is configured to switch from a first operating mode to a second, ventricular assist device operating mode for detecting cardiac arrhythmias and controlling delivery of anti-arrhythmia therapy during the ventricular assist device operating mode. The implantable medical device may receive a command from another medical device indicating co-implantation of a ventricular assist device with the implantable medical device in a patient and switch from the first mode of operating to the second mode of operating in response to receiving the command. Switching from the first mode to the second mode may include adjusting at least one control parameter used for controlling an electrical stimulation therapy deliverable by the implantable cardiac rhythm management medical device.

An implantable system includes a first leadless pacemaker (LP1) implanted in or on a first chamber of a heart and a second leadless pacemaker (LP2) implanted in or on a second chamber of the heart. The LP1 uses at least two of its electrodes to transmit and receive implant-to-implant (i2i) messages to and from the LP2. During one or more periods of time, the LP1 times delivery of pacing pulse(s) to the first chamber of the heart based on timing of cardiac activity associated with the second chamber of the heart detected by the LP1 itself. During one or more further periods of time, the LP1 times delivery of pacing pulse(s) to the first chamber of the heart based on timing of cardiac activity associated with the second chamber of the heart as determined based on one or more i2i messages received by the LP1 from the LP2.

An implantable system includes a first leadless pacemaker (LP1) implanted in or on a first chamber of a heart and a second leadless pacemaker (LP2) implanted in or on a second chamber of the heart. The LP1 is configured to time delivery of one or more pacing pulses delivered to the first chamber of the heart based on timing of cardiac activity associated with the second chamber of the heart detected by the LP1 itself. The LP1 is also configured to transmit implant-to-implant (i2i) messages to the LP2. The LP2 is configured to time delivery of one or more pacing pulses delivered to the second chamber of the heart based on timing of cardiac activity associated with the second chamber of the heart as determined based on one or more i2i messages received by the LP2 from the LP1.

An implantable system includes a first leadless pacemaker (LP1) implanted in or on a first chamber of a heart and a second leadless pacemaker (LP2) implanted in or on a second chamber of the heart. The LP1 is configured to time delivery of one or more pacing pulses delivered to the first chamber of the heart based on timing of cardiac activity associated with the second chamber of the heart detected by the LP1 itself. The LP1 is also configured to transmit implant-to-implant (i2i) messages to the LP2. The LP2 is configured to time delivery of one or more pacing pulses delivered to the second chamber of the heart based on timing of cardiac activity associated with the second chamber of the heart as determined based on one or more i2i messages received by the LP2 from the LP1.

Systems and methods for monitoring and treating patients with heart failure (HF) are discussed. The system may sense cardiac signals, and receives information about patient physiological or functional conditions. A stimulation parameter table that includes recommended values of atrioventricular delay (AVD) or other timing parameters maybe created at a multitude of patient physiological or functional conditions. The system may periodically reassess patient physiological or functional conditions. A therapy programmer circuit may dynamically switch between left ventricular-only pacing and biventricular pacing, or switch between single site pacing and multisite pacing based on the patient condition. The therapy programmer circuit may adjust AVD and other timing parameters using the cardiac signal input and the stored stimulation parameter table. A HF therapy may be delivered according to the determined stimulation site, stimulation mode, and the stimulation timing.

A leadless pacemaker device configured to provide for an intra-cardiac pacing, including: processing circuitry configured to generate ventricular pacing signals for stimulating ventricular, and a reception device for receiving a sensing signal indicative of an atrial activity, wherein the processing circuitry is configured to detect an atrial event derived from said sensing signal, wherein the atrial event is a valid atrial sense event, where a series of atrial events lie within a range for a normal atrial rate, and/or when the atrial rate variability is within a certain range indicating a regular atrial rhythm, wherein in case a valid atrial sense event is detected, the processing circuitry is further configured to: determine: ventricular pacing events according to atrial events, calculate ventricular-atrial time delays, determine a correction value based a measured time delay and the calculated time delay, and adjust the ventricular pacing timing based on the correction value.

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.