The effect of biventricular pacing on cardiac function after open heart surgery

Background: Temporary postoperative pacing could enhance recovery of the cardiac function. The right ventricular pacing (RV) is commonly used, but it can cause dyssynchronous contraction of both ventricles. Biventricular pacing (BV) could improve the systolic function by synchronizing the ventricular contraction. The aim of this study is to evaluate the effectiveness of biventricular pacing in improving the hemodynamics in the early postoperative period compared to other pacing modes. Methods: This is a clinical crossover trial including 50 patients who underwent open cardiac surgery in the period from September 2017 to September 2018. Mean age was 46.78± 12.09 years, and 50% were males. Temporary pacing leads were attached to the anterior wall of the right ventricle 1-2 cm paraseptally and the lateral wall of left ventricle 1-2 cm paraseptally. Each patient was paced for 3 minutes in the first 1-4 postoperative hours with 20 minutes washout period between different pacing modes. Study endpoints included cardiac output, ejection fraction (EF) and wall motion abnormality. Results: Biventricular and right ventricular pacing increased postoperative cardiac output (6.31± 1.28 and 5.2±0.72 L/min; respectively), but BV pacing was superior to RV pacing (P-value <0.001). The effect of BV pacing was more evident in patients with EF < 50% (7.27± 0.895 vs. 5.26 ± 0.634 L/min; p< 0.001). The postoperative EF improved during BV pacing (53.16± 4.71%) compared to RV pacing (49.4± 4.07%; P-value <0.001). Both BV and RV pacing were associated with less paradoxical septal wall motion abnormality (P-value <0.001). Conclusions: Temporary postoperative biventricular pacing improves hemodynamics compared to right ventricular and no pacing. Routine BV pacing is recommended especially in patients with low ejection fraction