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.