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.

Techniques and systems for monitoring cardiac arrhythmias and delivering electrical stimulation therapy using a subcutaneous device (e.g. subcutaneous implantable (SD)) and a leadless pacing device (LPD) are described. In one or more embodiments, a computer-implemented method includes sensing a first electrical signal from a heart of a patient through a SD. The first signal is stored into memory and serves as a baseline rhythm for a patient. Subsequently, a second signal is sensed from the heart through the SD. A cardiac condition can be detected within the sensed second electrical signal through the SD. A determination is made as to whether cardiac resynchronization therapy (CRT) is appropriate to treat the detected cardiac condition. A determination can then be made as to the timing of pacing pulse delivery to cardiac tissue through a leadless pacing device (LPD). The LPD receives communication from the SD requesting the LPD to deliver CRT to the heart. The SD senses and extracts data from a third electrical signal from the heart of the patient to determine whether the pacing by LPD provided efficacious resynchronization or whether the delivery and timing of the LPD pulse should be modified.

An example of a system for pacing through multiple electrodes in a ventricle includes a sensing circuit to sense cardiac signal(s), a pacing output circuit to deliver pacing pulses, a heart sound sensor to sense a heart sound signal, and a control circuit to control the delivery of the pacing pulses. The control circuit includes a heart sound detector to detect heart sounds using the heart sound signal, an electrical event detector to detect cardiac electrical events using the cardiac signal(s), a measurement module to measure an optimization parameter using the detected heart sounds, and an optimization module to approximately optimize one or more pacing parameters using the measured optimization parameter. The one or more pacing parameters include an electrode configuration parameter specifying one or more electrodes selected from the multiple electrodes in the ventricle for delivering ventricular pacing pulses to that ventricle.

The present disclosure pertains to cardiac pacing methods and systems, and, more particularly, to cardiac resynchronization therapy (CRT). In particular, the present disclosure pertains to determining whether a patient is experiencing atrial fibrillation (AF). If the patient is experiencing AF, the efficacy of CRT is determined. A signal is sensed in response to a ventricular pacing stimulus. Through signal processing, a number of features are parsed from the signal and a determination is made as to whether the ventricular pacing stimulus evoked a response from the ventricle.

Methods, devices and program products are provided for under control of one or more processors within an implantable medical device (IMD). Sensing near field (NF) and far field (FF) signals are between first and second combinations of electrodes coupled to the IMD. The method applies an arrhythmia detection algorithm to the NF signals for identifying events within the NF signal and designates events marker based thereon and monitors the event markers to detect a candidate arrhythmia condition in the NF signals. The candidate under-detected condition comprises at least one of an under-detected arrhythmia or over-sensing. In response to detection of the candidate arrhythmia condition, the method analyzes the FF signals for a presence of an under-detected arrhythmia indicator. The method delivers an arrhythmia therapy based on the presence of the under-detected arrhythmia indicator in the FF signals and the candidate under-detected arrhythmia condition in the NF signals.

An intracardiac pacemaker device, comprising a housing that is configured to be implanted entirely within a ventricle (V) of a heart (H), an electronic module for generating pacing pulses, a battery for supplying energy to the electronic module, an elongated lead extension protruding from the housing, at least a first electrode arranged on the elongated lead extension, and a pacing electrode and a return electrode for applying the pacing pulses to cardiac tissue, wherein the pacing electrode is arranged on the housing. The electronic module is electrically coupled to the pacing electrode via the housing, and wherein the electronic module is configured to carry out measurements of electrical activity via the at least one first electrode of the elongated lead extension.

A cardiac stimulation system and associated capture management method are provided in which capture and device longevity are improved. The device determines a series of capture thresholds. Capture threshold is the minimum pulse level (pulse energy or pulse amplitude or pulse width) that captures the heart. Each determination requires delivery of pacing pulses at several (at least two) known levels (pulse energy, pulse amplitude and/or pulse width) over time. The individual determined capture thresholds are combined into a set and the variability of the set is used to set the safety margin. The greater the variability in the capture thresholds, the bigger the safety margin.

A wireless cardiac stimulation device is disclosed comprising a controller-transmitter, a receiver, and a stimulating electrode, wherein the stimulating electrode and the receiver are separately implantable at cardiac tissue locations of the heart and are connected by a local lead. Having separately implantable receiver and stimulating electrodes improves the efficiency of ultrasound mediated wireless stimulation by allowing the receiver to be placed optimally for reception efficiency, thereby resulting in longer battery life, and by allowing the stimulating electrode to be placed optimally for stimulus delivery. Another advantage is a reduced risk of embolization, since the receiver and stimulating electrode ensemble is attached at two locations of the heart wall, with the connecting local leads serving as a safety tether should either the receiver or the stimulating electrode become dislodged.

A method and apparatus for treatment of hypertension and heart failure by increasing secretion of endogenous atrial hormones by pacing of the heart. Pacing is done during the ventricular refractory period resulting in premature atrial contraction that does not result in ventricular contraction. Pacing results in the atrial wall stress, peripheral vasodilation, ANP secretion. Concomitant reduction of the heart rate is monitored and controlled as needed with backup pacing.

Methods and devices for reducing ventricle filling volume are disclosed. In some embodiments, an electrical stimulator may be used to stimulate a patient's heart to reduce ventricle filling volume or even blood pressure. When the heart is stimulated in a consistent way to reduce blood pressure, the cardiovascular system may over time adapt to the stimulation and revert back to the higher blood pressure. In some embodiments, the stimulation pattern may be configured to be inconsistent such that the adaptation response of the heart is reduced or even prevented. In some embodiments, an electrical stimulator may be used to stimulate a patient's heart to cause at least a portion of an atrial contraction to occur while the atrioventricular valve is closed. Such an atrial contraction may deposit less blood into the corresponding ventricle than when the atrioventricular valve is opened throughout an atrial contraction.