An implantable pacemaker has a first housing and a second housing tethered to the first housing by an elongated electrical conductor. The elongated electrical conductor has a proximal end coupled to the first housing and a distal end coupled to the second housing and includes a signal line configured to carry an electrical signal between the first housing and the second housing.

A system for monitoring a subject for an arrhythmia includes an external monitoring device (EMD) configured to be disposed outside of a subject's body. The EMD includes a first communication component configured to receive, from a medical device, a first physiological parameter signal and an indication of a detected trigger event associated with a first portion of the first physiological parameter signal. The trigger event is indicative of a potential arrhythmia. The EMD also includes an analysis component configured to (1) identify a second portion of the first physiological parameter signal, where the second portion satisfies a discard criterion, (2) discard the second portion, and (3) perform an arrhythmia confirmation evaluation using a third portion of the first physiological parameter signal.

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.

Methods and systems of evaluating cardiac pacing in candidate patients for cardiac resynchronization therapy and cardiac resynchronization therapy patients are disclosed. The methods and systems disclosed allow treatments to be personalized to patients by measuring the extent of tissue capture from cardiac pacing under various therapy parameter conditions. Systems and methods of optimizing right ventricle only cardiac pacing are also disclosed.

An apparatus comprises an implantable cardiac signal sensing circuit configured to provide a sensed depolarization signal from a ventricle and a processor. The processor includes a signal analyzer module and a tachyarrhythmia discrimination module. The signal analyzer module is configured to determine a measure of stability of ventricular (V-V) depolarization intervals using the depolarization signal, and determine a rate of change of the measure of stability. The tachyarrhythmia discrimination module is configured to detect an episode of tachyarrhythmia using the depolarization signal, determine whether the detected tachyarrhythmia is indicative of atrial tachyarrhythmia using the determined rate of change, and provide the determination to a user or process.

An electrode apparatus includes a portable amplifier and a plurality of external electrodes to be disposed proximate a patient's skin. A portable computing apparatus is operably coupled to the electrode apparatus. The portable computing apparatus is configured to monitor electrical activity from tissue of a patient using the plurality of external electrodes to generate a plurality of electrical signals over time. The portable computing apparatus is configured to perform at least one of optimizing at least one parameter of the of the implantable pacing device based on the plurality of electrical signals and determining cardiac synchrony based on the plurality of electrical signals.

An implantable medical device performs a method that includes detecting a cardiac event interval that is greater than a P-wave oversensing threshold interval. In response to detecting the cardiac event interval greater than the P-wave oversensing threshold interval, the device determines the amplitude of the sensed cardiac signal and withholds restarting a pacing interval in response to the amplitude satisfying P-wave oversensing criteria. A pacing pulse may be generated in response to the pacing interval expiring without sensing an intrinsic cardiac electrical event that is not detected as a P-wave oversensing event.

System and methods for monitoring and/or controlling nerve activity in a subject are provided. In one embodiment, a system includes electrodes configured to be placed proximate to a subject's skin, and a signal detector configured to detect electrical signals using the electrodes. The system also includes a signal processor configured to receive the electrical signals from the signal detector, and apply a filter to the received electrical signals to generate filtered signals, the filter configured to attenuate at least signals having frequencies corresponding to heart muscle activity during a heartbeat. The signal processor is also configured to identify a skin nerve activity using the filtered signals, estimate a sympathetic nerve activity using the identified skin nerve activity, and further to generate a report indicative of the estimated sympathetic nerve activity. In some aspects, the system further includes a signal generator to deliver the electrical stimulation to the subject's skin.

Systems and methods for monitoring and treating patients with heart failure are discussed. The system may receive patient atrioventricular (AV) conduction characteristic under different heart rates or patient conditions. Stimulation parameters including stimulation timing parameters may be stored in a memory. The system may include a stimulation control circuit configured to determine a parameter update schedule indicating a timing at which to update stimulation parameter using patient AV conduction characteristic, and dynamically update at least a portion of the stored set of stimulation parameters at the determined parameter update schedule. For a specified heart rate or heart rate range, a stimulation parameter may be selected from the set of the stimulation parameters for use during cardiac stimulation.

VfA cardiac therapy uses an implantable medical device or system. The implantable medical device includes a tissue-piercing electrode implanted in the basal and/or septal region of the left ventricular myocardium of the patient's heart from the triangle of Koch region of the right atrium through the right atrial endocardium and central fibrous body. The device may include a right atrial electrode, a right atrial motion detector, or both. The device may be implanted completely within the patient's heart or may use one or more leads to implant electrodes in the patient's heart. The device may be used to provide cardiac therapy, including single or multiple chamber pacing, atrioventricular synchronous pacing, asynchronous pacing, triggered pacing, cardiac resynchronization pacing, or tachycardia-related therapy. A separate medical device may be used to provide some functionality for cardiac therapy, such as sensing, pacing, or shock therapy.