Dual-Site Left Ventricular Cardiac Resynchronization Therapy

Simultaneous stimulation of 2 left ventricular (LV) sites could enhance the effectiveness of cardiac resynchronization therapy (CRT). The aim of this study was to evaluate the acute hemodynamic response to dual-site LV CRT. Two LV pacing leads were successfully implanted in 12 CRT candidates (New York Heart Association classes III to IV, QRS >= 1.20 ms). Target positions were the lateral or posterolateral vein (site A) and anterior or anterolateral vein (site B). A conductance catheter was placed in the left ventricle for pressure-volume measurements. Tested CRT configurations were alternated by atrial overdrive pacing at a fixed rate and included site A and B single-site CRT and dual-site LV CRT (2 LV sites plus right ventricular apex) at 4 atrioventricular intervals. Overall, single-site LV CRT significantly enhanced stroke volume, stroke work, maximum pressure derivative, and conductance-derived indexes of LV synchrony when delivered in site A, whereas no significant changes were noticed with pacing in site B. Specifically, site-A pacing resulted in a higher stroke volume increase (LV pacing site associated with the best hemodynamic response [best-LV]) in 8 patients, and site-B pacing, in 4 patients. At intermediate atrioventricular intervals, dual-site LV CRT resulted in improved stroke volume, stroke work, maximum pressure derivative, and LV synchrony with respect to single-site CRT when delivered at the best-LV (all p <0.05). However, single-site CRT at best-LV produced results similar to dual-site LV CRT when the atrioventricular interval was optimized in each patient. In conclusion, adding a second LV lead does not result in further improvement in acute hemodynamic response with respect to standard CRT when the single LV pacing site and atrioventricular interval are optimal. (C) 2008 Elsevier Inc. (Am J Cardiol 2008;102:1687-1692)