Advantage of Right Ventricular Outflow Tract Pacing on Cardiac Function and Coronary Circulation in Comparison with Right Ventricular Apex Pacing

Background: The purpose of this study was to investigate the acute effect of right ventricular outflow tract (RVOT) pacing and right ventricular apex (RVA) pacing on synchronous ventricular activation and coronary flow dynamics. Methods: We enrolled 20 consecutive patients who underwent electrophysiologic study. Echocardiographic study including two-dimensional tissue tracking imaging and Doppler guide wire examination was performed during RVOT pacing and RVA pacing. Results: The improvement of left ventricular radial dyssynchrony (99 +/- 12 ms vs. 142 +/- 16 ms, P<.001), time-averaged peak velocities of coronary blood flow (54 +/- 18 cm/s vs. 47 +/- 17 cm/s, P = .007), and coronary microvascular resistance index (2.0 +/- 0.8 vs. 2.4 +/- 1.1, P = .028) was observed with RVOT pacing compared with RVA pacing. Conclusion: RVOT pacing might provide favorable effects on the left ventricular function and coronary flow dynamics over RVA pacing. (J Am Soc Echocardiogr 2010; 23: 1177-82.)