Systems and methods for monitoring and treating patients with heart failure are discussed. The system can store in a memory stimulation parameters, including stimulation timing parameters for a plurality of heart rate ranges. The system includes a plurality of timers with respective durations for the plurality of heart rate ranges. A stimulation control circuit can identify a target heart range in which a detected heart rate falls, and measure an atrioventricular (AV) conduction characteristic value in response to the timer for the target heart range being expired at the detected heart rate. The stimulation control circuit can update a stimulation parameter corresponding to the target heart rate range using the measured AV conduction characteristic. The updated stimulation parameter can be used in cardiac stimulation.

During a cardiac arrhythmia, defibrillation shocks from an implanted cardiac defibrillator are suppressed based on the sensing of electrical wavefront arrival times which indicate a supraventricular origin to the cardiac arrhythmia. In some embodiments, times of electrical wavefront arrival in at least two ventricular locations of the heart are sensed; one location being relatively superior, and one relatively inferior (e.g., relatively superior and inferior locations of a ventricular septum). In some embodiments, if the arrival time at the more inferior position is within a predetermined interval after arrival at the more superior position, delivery of defibrillation shocks are suppressed. In some embodiments, additional sensing of electrical wavefront arrival at one or more non-septal ventricular locations is performed, and defibrillation shock suppression is optionally itself suppressed if the additional sensing indicates that the wavefront initiated in a ventricular location.

An implantable device and associated method for delivering multi-site pacing therapy is disclosed. The device comprises a set of electrodes including a first and second left ventricular electrodes spatially separated from one another and a right ventricular electrode, all coupled to an implantable pulse generator. The processing circuit coupled to the implantable pulse generator, the processing circuit configured to determine whether a prospective heart failure condition has occurred and if so to trigger the pulse generator to switch from a first pacing mode to a second pacing mode, the first pacing mode comprising delivering only a first pacing pulse to a left ventricle (LV) and thereafter delivering an RV pacing pulse to the right ventricular electrode within a single cardiac cycle and the second pacing mode comprising delivering first and a second pacing pulses to the LV and thereafter delivering an RV pacing pulse to the right ventricular electrode within a single cardiac cycle.

This document discusses, among other things, systems and methods to receive physiologic information from a patient during different first and second pacing periods having respective, different first and second atrioventricular (AV) delays, determine first and second physiologic parameters using respective received physiologic information from the first and second pacing periods, and adjust the first AV delay using the determined first and second physiologic parameters, wherein the second AV delay is longer than the first AV delay.

Systems, interfaces, and methods are described herein for evaluation and adjustment cardiac therapy. The systems, interfaces, and methods may utilize, or include, a graphical user interface to display various information with respect to a plurality of external electrodes and electrical activity monitored using such external electrodes and to allow a user to adjust what information to display.

A method and device for dynamic device based AV delay adjustment is provided. The method comprises electrodes that are configured to be located proximate to an atrial (A) site and a right ventricular (RV) site. The method utilizes one or more processors for detecting an atrial paced (Ap) event or atrial sensed (As) event, and measures an AV interval corresponding to an interval between the Ap event or the As event and a sensed ventricular (Vs) event. The AV interval is associated with a current heart rate (HR). The method automatically dynamically adjusts a first AV delay based directly on the measured AV interval, identifies a scale factor associated with the current HR, calculates a second AV delay by scaling the first AV delay based on the scale factor and manages a pacing therapy, utilized by the IMD, based on the first and second AV delays.

In some examples, controlling delivery of CRT includes controlling an implantable medical device to deliver ventricular pacing according to a sequence of different values of a CRT parameter, and acquiring first and second electrograms from respective first and second electrode vectors. For each value of the CRT parameter, a value of a metric of comparison of a first activation interval between occurrences of a first fiducial of a cardiac cycle and a second fiducial of the cardiac cycle detected in the first electrogram to a second activation interval between occurrences of the first fiducial and the second fiducial detected in the second electrogram may be determined. A target value of the metric of comparison may be identified and an updated value of the CRT parameter determined based on the target value. The system then may control the IMD to deliver ventricular pacing at the updated value of the CRT parameter.

A system and method for designating between types of activation by a pulse generator configured to deliver a left ventricular (LV) pacing pulse at an LV pacing site as part of a cardiac resynchronization therapy (CRT) are provided. The system includes a sensing channel configured to collect cardiac activity (CA) signals along at least one sensing vector extending through a septal wall between the LV and right ventricle (RV). The CA signals are indicative of one or more beats and include a pre-LV pacing segment indicative of cardiac activity preceding the LV pacing pulse and a post-LV pacing segment indicative of cardiac activity following the LV pacing pulse. The system includes memory to store program instructions. One or more processors are configured to implement the program instructions to analyze the pre-LV pacing segment to identify a first myocardium activation (MA) characteristic of interest (COI). The system analyzes the post-LV pacing segment to a second MA COI, compares the first and second MA COI to first and second MA criteria, respectively, designates the CA signals to be indicative of one of a fusion beat, a capture beat or a pseudofusion beat based on the comparison of the first and second MA COI to first and second MA criteria and store a result of the designation.

Pacemaker-initiated atrial fibrillation during competitive atrial pacing is a common arrhythmia with potentially serious consequences The novel pacing method proposes a novel way to automatically detect and diagnose competitive atrial pacing, and to deliver an intervention via a pacing stimulus in the atrium simultaneously with delivering a pacing stimulus in the ventricle, and doing this after a longer waiting period. By doing this, potentially hazardous scenarios causing atrial fibrillation in competitive atrial pacing are avoided, while the rhythm regularity and the synchrony between the upper and lower chambers of the heart are maintained. At the same time, the vicious cycle of retrograde conduction from the ventricle to the atrium—the culprit of the problem—is terminated and not allowed to reoccur for several subsequent cardiac cycles, thereby preventing the extended propagation of repetitive non-reentrant ventriculo-atrial synchrony.

A method for controlling an adaptive pacing therapy that includes utilizing one or more processors to perform measuring an atrial-ventricular (AV) interval corresponding to an interval between an atrial paced (Ap) event or an atrial sensed (As) event and a sensed ventricular (Vs) event, setting an AV delay based on the AV interval, and measuring an S1 heart sound characteristic of interest (COI) while utilizing the AV delay in connection with delivering a pacing therapy by the IMD. The one or more processors also perform adjusting the AV delay, repeating the measuring, and adjusting to obtain a collection of S1 heart sound COIs and corresponding AV delays, selecting one of the AV delays, that corresponds to a select one of the S1 heart sound COIs, as a resultant AV delay, and managing the pacing therapy, utilized by the IMD, based on the resultant AV delay.