The effect of biventricular pacing after coronary artery bypass grafting: a prospective randomized trial of different pacing modes in patients with reduced left ventricular function.

Objectives: Biventricular pacing acutely improves left ventricular function in patients with heart failure and left ventricular dyssynchrony. Pressure-volume loop analysis has shown acute perioperative hemodynamic benefits of biventricular pacing immediately after weaning from cardiopulmonary bypass in patients undergoing coronary artery bypass grafting, but whether these effects can be maintained for the early postoperative period is unclear. We hypothesized that biventricular pacing is superior to atrioventricular universal pacing at right ventricular outflowtract and atrial inhibited pacing in patients undergoing coronary artery bypass grafting.

Methods: Ninety-four patients (mean age, 67 +/- 9 years; mean ejection fraction, 35% +/- 4%) were prospectively randomized to undergo biventricular, atrioventricular universal, or atrial inhibited pacing at 90 beats/min for 96 postoperative hours. Clinical end points and postoperative hemodynamics, aminoterminal pro-brain natriuretic peptide, inotropic support, atrial fibrillation, ventricular arrhythmias, and renal function were evaluated.

Results: Diastolic pulmonary arterial pressure, mean arterial pressure, mixed venous saturation, cardiac index, and cardiac power index did not differ significantly among groups for all time points. Neither raw aminoterminal pro-brain natriuretic peptide nor differential from preoperative values differed significantly among groups at any time point. Median intensive care unit stay (19.5 hours) did not differ significantly by pacing mode. Incidences of postoperative atrial fibrillation were 40% for atrial inhibited, 29% for atrioventricular universal, and 37% for biventricular (differences not significant). Renal function was unaffected by pacing mode.

Conclusion: Despite short-term hemodynamic benefits for patients with reduced left ventricular function, biventricular pacing did not lead to improved postoperative hemodynamics or clinical outcome.