Tissue Doppler Echocardiographic Evidence of Reverse Remodeling and Improved Synchronicity by Simultaneously Delaying Regional Contraction After Biventricular Pacing Therapy in Heart Failure

Abstract

Background — Biventricular pacing has been proposed to improve symptoms and exercise capacity in patients with advanced heart failure and wide electrocardiographic wave complexes. This study investigated the effect of biventricular pacing on reverse remodeling and the underlying mechanisms. Methods and Results — Twenty-five patients with NYHA class III to IV heart failure and electrocardiographic wave complex duration >140 ms receiving biventricular pacing therapy were assessed serially up to 3 months after pacing and when pacing was withheld for 4 weeks. Tissue Doppler echocardiography was performed using a 6-basal, 6-mid segmental model to assess the time to peak sustained systolic contraction (T _S ). There was significant improvement of ejection fraction, dP/dt, and myocardial performance index; decrease in mitral regurgitation, left ventricular (LV) end-diastolic (205±68 versus 168±67 mL, P P S to a timing close to the latest (usually the lateral) segment abolishing the intersegmental difference in T _S and decreasing the standard deviation of T _S within the left ventricle (37.7±10.9 versus 29.3±8.3 ms, P P Conclusions — Biventricular pacing reverses LV remodeling and improves cardiac function. Improvement of LV mechanical synchrony seems to be the predominant mechanism.