Shallow stitching close to the rim of the ventricular septal defect eliminates injury to the right bundle branch

Background. Complete right bundle branch block carries a deleterious effect on the long-term outcome of patients who undergo surgical treatment of the perimembranous ventricular septal defect. We describe a novel suturing method to reduce the prevalence of complete right bundle branch block. Methods. From March 1996 through December 2000, 48 consecutive patients with perimembranous ventricular septal defect underwent patch closure using shallow stitches placed close to the rim (group 1). The same number of patients was randomly selected from those who had previously undergone surgery using deep stitches placed distant from the rim (group 2). Postoperative electrocardiograms were reviewed to compare the prevalence of complete right bundle branch block between groups. A morphologic study of the conduction system was performed to identify the vulnerable segment of the right bundle branch where the surgical damage tended to occur. Additional analyses were made to determine whether younger age and right ventriculotomy increased the prevalence of complete right bundle branch block. Results. The prevalence of complete right bundle branch block in group 1 (6.3%) was significantly (p < 0.0001) lower than in group 2 (43.8%). The result was consistent with the morphologic finding that stitches of group 2 tended to damage the right bundle branch and those of group 1 did not. The younger age and right ventriculotomy did not increase the prevalence of complete right bundle branch block. Conclusions. Shallow stitches placed close to the rim of the perimembranus ventricular septal defect eliminate injury to the right bundle branch.