Response of mean arterial pressure to temporary biventricular pacing after chest closure during cardiac surgery

Objectives: We have previously demonstrated that biventricular pacing increased cardiac output within 1 hour of weaning from cardiopulmonary bypass in selected patients. To assess the possible sustained benefit, we reviewed in the present study the effects of biventricular pacing on the mean arterial pressure after chest closure. Methods: A total of 30 patients (mean ejection fraction 35% ± 15%, mean QRS 119 ± 24 ms) underwent coronary bypass and/or valve surgery. The mean arterial pressure was maximized during biventricular pacing using atrioventricular delays of 90 to 270 ms and interventricular delays of +80 to -80 ms during 20-second intervals in random sequence. Optimized biventricular pacing was finally compared with atrial pacing at a matched heart rate and to a sinus rhythm during 30-second intervals. Vasoactive medication and fluid infusion rates were held constant. The arterial pressure was digitized, recorded, and integrated. Statistical significance was assessed using linear mixed effects models and Bonferroni's correction. Results: Optimized atrioventricular delay, ranging from 90 to 270 ms, increased the mean arterial pressure 4% versus nominal and 7% versus the worst (P < .001). Optimized interventricular delay increased pressure 3% versus nominal and 7% versus the worst. Optimized biventricular pacing increased the mean arterial pressure 4% versus sinus rhythm (78.5 ± 2.4 vs 75.1 ± 2.4 mm Hg; P = .002) and 3% versus atrial pacing (76.4 ± 2.7 mm Hg; P = .017). Conclusions: Temporary biventricular pacing improves the hemodynamics after chest closure, with effects similar to those within 1 hour of bypass. Individualized optimization of atrioventricular delay is warranted, because the optimal delay was longer in 80% of our patients than the current recommendations for temporary postoperative pacing.