Abstract 2934: Cardiac Resynchronization Therapy with Triple-Site Pacing is Superior to Bi-Site Pacing in Improving Left Ventricular Function and Dyssynchrony
Background. Among the patients receiving cardiac resynchronization therapy (CRT), 20 to 30% do not respond to the therapy. The aim of this study was to examine the impact of CRT with triple-site pacing (tri-CRT) on the left ventricular (LV) function and dyssynchrony, as compared to CRT with standard bi-site pacing (bi-CRT).
Methods. Twenty-seven patients with NYHA class III (n = 20) and IV (n = 7) heart failure were studied. For the tri-CRT, the right ventricular (RV) lead was separated into two leads with a Y connector, and one lead was anchored at the RV apex and the other in the RV outflow tract. The LV lead was positioned in the postero-lateral or lateral cardiac vein. Bi-CRT was performed with RV apical and LV leads. The LV function was assessed by a catheter based hemodynamic evaluation. The LV dyssynchrony was assessed with tissue Doppler imaging, and the time to peak systolic myocardial velocity (Ts) and early diastolic myocardial velocity (Td) were measured in 12 LV segments. The standard deviation of the Ts in the 12 segments (Ts-SD) was used as the systolic dyssynchrony index, and the standard deviation of Td (Td-SD) was used as the diastolic dyssynchrony index.
Results. Tri-CRT resulted in a better hemodynamic response and resynchronization, as compared to bi-CRT (table⇓). There were significant differences in the values of the tau and Td-SD between the tri-and bi-CRT. Tri-CRT also increased the cardiac output (CO) more significantly than bi-CRT. The change in the CO between tri- and bi-CRT was clearly correlated with the change in the dp/dt max (r = 0.56, p = 0.01) and tau (r = −0.61, p = 0.005) between tri- and bi-CRT.
Conclusion. Tri-CRT has greater beneficial acute effects on the LV function and dyssynchrony than bi-CRT. Therefore, tri-CRT may become an efficient option in patients who do not respond to bi-CRT.