Acute electromechanical effects of atrioventricular coupled pacing in patients with heart failure

Postextrasystolic potentiation (PESP) is a property of cardiac tissue whereby two closely timed depolarizations cause the subsequent contraction to be of increased magnitude.

Ten subjects were studied in a single-blind study to evaluate the safety and performance of an atrioventricular coupled pacing (A-VCP) algorithm to produce sustained PESP among subjects with moderate heart failure. The primary end points were algorithm safety, patient perception, and cardiac function. The effects of A-VCP on cardiac function were assessed by comparing echocardiographic parameters before and after 15 to 20 minutes of A-VCP. A-VCP produced no arrhythmic episodes, ejection fraction increased by 8 ejection fraction points (31%) (P < or = .001), end-systolic volume decreased by 10% (P < or = .05), and a trend toward increasing end-diastolic volume was observed (P = .084). Stroke volume increased by 43% (P < or = .001), and the pulse rate decreased by 41% (P < or = .001) during A-VCP. This resulted in decreased cardiac output of 15% (P < or = .05). Six of the 10 subjects felt no effects from A-VCP, and four subjects felt a change with A-VCP turned on.

Short-term A-VCP was found to be safe and well tolerated in a majority of patients. Hemodynamic effects were mixed with improved ejection fraction and stroke volume but decreased cardiac output.