Background: Asynchronous patterns of contraction and relaxation may contribute to hemodynamic and functional impairment in heart failure. In 1993, we introduced biventricular pacing as a novel method to treat heart failure by synchronous stimulation of the right and left ventricles after an appropriate atrioventricular delay. The objectives of this study were to assess the early and long-term effects of this therapy on functional capacity and left ventricular function in patients with severe heart failure and left bundle branch block.
Methods and results: Twelve patients with end-stage congestive heart failure, sinus rhythm and complete left bundle branch block were treated with biventricular stimulation at optimized atrioventricular delay. The NYHA functional class and maximal bicycle exercise capacity were assessed. Systolic and diastolic left ventricular function were studied with echocardiography and radionuclide angiography. Data was collected at various intervals during 1-year follow-up. Cumulative survival [95% CI] was 66.7% [40.0,93.4] at 1 year and 50 % [21.8, 78.2] at 2 and 3 years. Median NYHA class improved from class IV to class II at 1 year (p=0.008). After 6 weeks an increase in exercise capacity occurred, which was sustained. A less restrictive left ventricular filling pattern, an increase in dP/dt and left ventricular ejection fraction, and a decrease in mitral regurgitation were observed early and long-term.
Conclusions: Biventricular pacing at optimized atrioventricular delay results in improvement in functional capacity, which is associated with improved systolic and diastolic left ventricular function, and a decrease in mitral regurgitation during short- and long-term follow-up.