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.

Pacing parameters may be adjusted to increase the cardiac output of a patient's heart while a patient is awake and/or active and the demand placed on the heart may be greatest, and to decrease or hemodynamic efficiency while a patient is at rest so that the heart itself has time to rest before the next period of higher demand for efficiency begins. This may aid in lessening the strain placed on the heart by making the heart work hard when needed such as when the patient is active, and by permitting the heart to “rest” when the patient is relatively inactive.

A method for identifying reversible cardiac dyssynchrony (RCD) of a patient and treating the RCD measures an event relating to a rapid increase in the rate of pressure increase within the left ventricle. The method calculates a first time delay between the event and a first reference time. If the first time delay is longer than a set fraction of electrical activation of the heart, then the presence of cardiac dyssynchrony in the patient is identified. Pacing is applied to the heart, and a second time delay between the event following pacing and a second reference time following pacing is calculated. If the second time delay is shorter than the first time delay, the method identifies a shortening of a delay to onset of myocardial synergy, OoS, thereby identifying the presence of RCD in the patient. Treatment of the RCD is performed.

Implantable medical devices such as leadless cardiac pacemakers (LCP) may be configured to be delivered to a target location within the heart over a guide wire. In some cases, using a guide wire for delivery facilitates placement of devices in regions not otherwise easily reached. An LCP may include a housing and a wire lumen disposed relative to the housing. The wire lumen may be configured to allow the LCP to slide over a guide wire. In some cases, the guide wire may include a guide wire electrode that may be used to test potential implantation sites.

Systems and methods are described herein for assisting a user in identification of interventricular (V-V) delay for cardiac therapy. The systems and methods may monitor electrical activity of a patient using external electrode apparatus to provide electrical heterogeneity information for a plurality of different V-V intervals and may identify a V-V interval based on the electrical heterogeneity information.

Systems and methods involve an intrathoracic cardiac stimulation device operable to provide autonomous cardiac sensing and energy delivery. The cardiac stimulation device includes a housing configured for intrathoracic placement relative to a patient's heart. A fixation arrangement of the housing is configured to affix the housing at an implant location within cardiac tissue or cardiac vasculature. An electrode arrangement supported by the housing is configured to sense cardiac activity and deliver stimulation energy to the cardiac tissue or cardiac vasculature. Energy delivery circuitry in the housing is coupled to the electrode arrangement. Detection circuitry is provided in the housing and coupled to the electrode arrangement. Communications circuitry may optionally be supported by the housing. A controller in the housing coordinates delivery of energy to the cardiac tissue or cardiac vasculature in accordance with an energy delivery protocol appropriate for the implant location.

Methods and/or devices may be configured to monitor ventricular activation times and modify an atrioventricular delay (AV delay) based on the monitored ventricular activation times. Further, the methods and/or devices may determine whether the AV delay should be modified based on the measured activation times before modifying the AV delay.

The disclosure relates to a device including a plurality of electrodes for stimulation of both ventricles with application of an atrioventricular delay and of an interventricular delay, a processor configured to multidimensionally measure an interventricular conduction delay, and monitor the evolution of a patient's condition. For the multidimensional measurement of the interventricular conduction delay, the device produces stimulation of one of the ventricles and collects, in the other ventricle, two endocardial electrogram signals on separate respective channels, giving two respective temporal components. Both temporal components are combined in one single parametric 2D characteristic representative of the cardiac cycle, and a comparison is made with reference descriptors for deriving an index representative of the evolution of the patient's condition.

According to some embodiments, a device operates by comparative morphological analysis of depolarization signals collected in spontaneous rhythm on separate respective channels, with two temporal components combined into a single 2D parametric VGM vectogram characteristic. Similarity quantification methods evaluate a variation over time of a descriptor parameter of a current VGM compared to a stored previous reference VGM. This variation is compared with predetermined thresholds to diagnose an occurrence of remodeling or reverse remodeling in a patient, and/or to detect a lead failure or an occurrence of ischemia. The descriptor parameter is a function of a velocity vector of the VGM, a comparison relating to a correlation coefficient between respective magnitudes of a current VGM velocity vector and of a reference VGM velocity vector, and an average angle between these respective velocity vectors.

An apparatus for coupling to a plurality of electrodes implantable at a plurality of tissue sites of a heart chamber of a subject. The apparatus including a stimulus circuit configured to provide an electrical cardiac pacing stimulation to the plurality of electrodes, a switching circuit configured to select electrodes of the plurality of electrodes for electrical coupling to the stimulus circuit, and a control circuit including a heart rate sub-circuit configured to determine heart rate; and a pacing site activation sub-circuit configured to selectively change which electrodes of the plurality of electrodes are used to provide the electrical cardiac pacing stimulation therapy according to the determined heart rate.