[Interpretation of the right bundle-branch block appearing after repair of ventricular septal defect].

Based on a study of 43 cases the authors attempt to assess the exact aetiology of the appearance of right bundle branch block, which is seen very frequently after repair of a ventricular septal defect. A comparison of the electrocardiograms with the anatomical type of VSD, the surgical approach, and the size of the septal defect would seem to indicate that a monofascicular block by a lesion of the right branch of the bundle of His is responsible. The correlations are not, however, absolute, and in a certain number of cases a simple peripheral lesion was to blame. The importance of precise knowledge of the case of the branch is that it is possible that first a bi- and then a tri-fasicular block will develop; this means that complete atrioventricular block is one of the long-term sequelae of surgery. In the authors' experience of 43 cases, only one tri-fascicular block developed.