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.