[Right ventricular diastolic overloading in left bundle-branch block]

The combination of left bundle-branch block with right ventricular hypertrophy is said to be exceptional. Faced with this possibility, many authors consider a diagnosis of right ventricular hypertrophy as impossible. The two cases reported were found in a total of approximately 10,000 vectorcardiograms. Starting in 1950, Laham drew attention to the special morphology of precordial left bundle-branch block when there is right ventricular hypertrophy. In 1971, Chou and Helm suggested vectorcardiographic criteria for right ventricular hypertrophy in the case of left bundle-branch block--right posterior shift of the QRS loop and clockwise rotation on the horizontal plane. These criteria are satisfied in the first case, i.e. partial atrioventricular canal, but not in the second, i.e. ostium secundum defect. In both cases, the appearance of the left bundle-branch block is very atypical.