Effect of different epicardial ventricular pacing sites on left ventricular function in awake dogs

Abstract

Left ventricular performance was assessed during both atrial and sequential and nonsequential ventricular pacing from multiple epicardial sites in 12 awake dogs. All animals had an electromagnetic flow probe chronically implanted on the ascending aorta and pressure catheters implanted in the aorta and left ventricle. The mean pacing rate was 106 beats/min. Compared to results obtained with right atrial pacing alone, sequential ventricular pacing resulted in a 14 percent decrease in left ventricular stroke volume. This decrease is most likely due to the ventricular asynchrony from ectopic depolarization. No significant differences in the hemodynamic variables measured (stroke volume, left ventricular end-diastolic pressure, aortic pressure) or computed (stroke work, peak power) could be detected among any of the right or left ventricular pacing sites during either sequential or nonsequential pacing. From these data we conclude that no optimal site for epicardial ventricular pacing exists.