Abstract
Intraventricular conduction defects are common following repair of various forms of congenital heart disease. Such defects may affect adversely the long-term prognosis of patients in whom cardiac hemodynamics were adequately restored. The site of the conduction defect may be the reason for the different prognoses reported for patients. The so-called trifascicular block pattern which sometimes occurs following open heart surgery is probably due to a more extensive lesion to the branching and penetrating parts of the His bundle rather than additional injury to the posterior left bundle branch fibers. Transiet complete heart block in the immediate postoperative period seems to be a predictor for late development of complete heart block or sudden death at least as powerful as right bundle branch block and left anterior hemiblock.