Abstract: A dual chamber pacemaker is provided having capability for adjusting the AV escape interval so as to optimize the timing of delivered ventricular pace pulses for therapy of patients with cardiomyopathy. The pacemaker system continually monitors to determine when a delivered pace pulse results in a fusion beat, and periodically adjusts the AV escape interval in accordance with the percentage or rate of incidence of such fusion beats. In one specific embodiment, the pacing system determines the percentage of delivered ventricular pace pulses which are followed by fusion beats over a predetermined number of intervals, and decrements AV escape interval when such percentage is not below a predetermined minimum. The pacing system also periodically increments AV escape interval when the rate of fusion beats is acceptable, thereby providing a closed loop system for maintaining the AV interval at an optimally long value consistent with maximizing full capture by delivered ventricular pace pulses.

Abstract: A dual chamber pacemaker is provided having capability for adjusting the AV escape interval so as to optimize the timing of delivered ventricular pace pulses for therapy of patients with cardiomyopathy. The pacemaker system continually monitors to determine when a delivered pace pulse results in a fusion beat, and periodically adjusts the AV escape interval in accordance with the percentage or rate of incidence of such fusion beats. In one specific embodiment, the pacing system determines the percentage of delivered ventricular pace pulses which are followed by fusion beats over a predetermined number of intervals, and decrements AV escape interval when such percentage is not below a predetermined minimum. The pacing system also periodically increments AV escape interval when the rate of fusion beats is acceptable, thereby providing a closed loop system for maintaining the AV interval at an optimally long value consistent with maximizing full capture by delivered ventricular pace pulses.

Abstract: In a dual chamber cardiac pacemaker, a method and apparatus for determining an atrioventricular (AV) delay interval to maintain optimal left heart AV mechanical synchrony and function. When the intrinsic or paced atrial heart rate is stable, test AV delay intervals are selected and delivered as right ventricular absolute blood pressures (RVP) are measured at the opening of the pulmonary valve. The opening of the pulmonary valve is determined by the peak rate of change in the RVP (dP/dt) following depolarization of the right ventricle. The test AV delay interval providing the lowest amplitude RVP at the peak dP/dt, indicating the lowest pulmonary blood pressure, is selected as the optimal AV delay.

Abstract: An acoustic sensor is located in association with a patient's heart to detect abnormal heart sounds and a processor isolates abnormal heart sounds therefrom. The characteristics of these heart sounds are monitored while adjustments are made to the timing of pacing pulses to achieve a better heart function through pacing therapy. Particular adaption to cardiomyopathy is shown.

Abstract: A dual chamber pacemaker and a method of employing the pacemaker to accomplish atrial synchronized ventricular pacing with complete ventricular capture by control of the A-V escape intervals of the pacer. The maximum A-V escape interval effective to accomplish complete ventricular capture is determined and compared to intrinsic A-V conduction time to derive an offset interval. The offset interval is subtracted from the initially measured conduction time to select initial A-V escape interval durations and is subtracted from A-V conduction times measured after implant of the pacemaker to automatically adjust A-V escape interval durations of the pacemaker to maintain complete ventricular capture.