The effects of surgically induced right bundle branch block on left ventricular function after closure of the ventricular septal defect

Objective: To determine the long-term significance of right bundle branch block on left ventricular systolic and diastolic function in children subsequent to surgical closure of ventricular septal defect. Methods: We studied 26 children who underwent surgical closure of a ventricular septal defect 11 +/- 2 years postoperatively by use of conventional and tissue Doppler echocardiography, comparing the findings to those obtained from a control group. Of those having surgical correction 14 had postoperative right bundle branch block. Results: Irrespective of the presence of right bundle branch block, the peak systolic velocity of the mitral ring was lower in those undergoing surgical correction, with values of 5.2 +/- 1.4cm/s in those with right bundle branch block, 5.4 +/- 1.2 cm/s in those without right bundle branch block after surgical correction, and 6.6 +/- 1.0 cm/s in the control subjects (p < 0.01). In terms of diastolic function, the early septal velocity of transmittal inflow divided by the early diastolic mitral annular velocity was significantly higher in children with right bundle branch block, at 12 +/- 3.0 cm/s compared to 8.4 +/- 1.5 cm/s in the control subjects (p < 0.01), but not significantly higher in the children without right bundle branch block after correction compared to the control group. The fractional shortening percentage was similar in both patients and control subjects. The changes noted in left ventricular function were not significantly related to age at surgery, the period of follow-up, or the surgical method. Conclusions: Systolic long axis function is significantly reduced in children after surgical closure of ventricular septal defects, irrespective of the presence of right bundle branch block. Diastolic dysfunction, in contrast, was observed primarily in children with postoperative right bundle branch block.