Impact of biventricular and left ventricular pacing on hemodynamics and left ventricular dyssynchrony compared with right ventricular pacing in the early postoperative period following cardiac surgery.

OBJECTIVES

The aims of this study were to test the hypotheses that in the postoperative period following corrective surgery for congenital heart defects: (i) atrio-right ventricular (RA-RV) pacing decreases cardiac output (CO) compared with right atrial (RA) pacing, (ii) atrio-biventricular (RA-BiV) and left ventricular (RA-LV) pacing improves CO compared with RA-RV pacing.

STUDY DESIGN

Prospective observational study.

PATIENTS

Children 0-2years of age referred for surgery of congenital heart defects were studied during intrinsic rhythm and atrial, atrio-right ventricular, atrio-left ventricular and atrio-biventricular pacing. CO, extrapolated from mean systolic aortic velocity (MSAV), and left ventricular dyssynchrony were assessed using transthoracic echocardiography.

RESULTS

RA-RV pacing induced a significant decrease in CO (MSAV 0.52±0.19m/s to 0.46±0.16m/s, p=0.01) and a significant increase in LV dyssynchrony (8.7±7.9ms to 33±21ms, p=0.001). RA-BiV pacing induced a significant increase in CO (MSAV 0.46±0.16m/s to 0.52±0.18m/s, p=0.01) and a significant decrease in LV dyssynchrony (33±21ms to 7±4ms, p=0.0003) compared with RA-RV pacing. RA-LV pacing induced a significant decrease in LV dyssynchrony (33±21ms to 9±7ms, p=0.0007) without a significant improvement of CO compared with RA-RV pacing.

CONCLUSIONS

RA-BiV pacing improves CO compared with RA-RV pacing in the early postoperative period following pediatric cardiac surgery. This improvement is related to a reduction in left ventricular dyssynchrony.