The Impact of Atrio-Biventricular Pacing on Hemodynamics and Left Ventricular Dyssynchrony Compared With Atrio-Right Ventricular Pacing Alone in the Postoperative Period After Cardiac Surgery

Objectives: The aims of this study were to test the hypotheses that in the postoperative period after coronary artery bypass graft surgery (1) atrio-right ventricular (RA-RV) pacing induces a decrease in cardiac output compared with RA pacing alone and (2) atrio-biventricular (RA-BiV) pacing improves CO compared with RA-RV pacing. Design: A prospective observational study. Setting: A single-center university hospital. Participants: Patients referred for coronary artery bypass graft surgery. Interventions: Patients were studied during atrial, RA-RV, and RA-BiV pacing. Cardiac output (echocardiography) and left ventricular dyssynchrony were assessed at each step. Measurements and Main Results: RA-RV pacing induced a significant decrease in cardiac output (4.3 ± 1.0 to 3.7 ± 0.8 L/min, p <0.01) and a significant increase in left ventricular dyssynchrony (13 ± 12 to 80 ± 25 milliseconds, p <0.01). Biventricular pacing induced a significant increase in cardiac output (3.7 ± 0.8 to 4.5 ± 1.0 L/min, p <0.01) and a significant decrease in left ventricular dyssynchrony compared with right ventricular pacing (80 ± 25 to 21 ± 16 milliseconds, p <0.05). Conclusions: RA-BiV pacing improves cardiac output compared with RA-RV pacing in the postoperative period after coronary artery bypass graft surgery. This improvement is related to an improvement in left ventricular synchronicity.