Familial Right Bundle-Branch Block, Left Axis Deviation, Complete Heart Block, and Early Death

Abstract

A patient with right bundle-branch block and left axis deviation who later developed complete heart block had a family history suggestive of familial bundle-branch disease and heart block. Investigation of 59 members in four generations of the family showed 26 with abnormal electrocardiograms and 6 with a history of heart block. Seven have right bundle-branch block and left axis deviation; seven have right bundle-branch block, left axis deviation, and intermittent complete heart block. All affected members have conduction abnormalities as the only manifestation of heart disease. The genetic defect appears to be transmitted as an autosomal dominant trait with varying expressivity. This conduction abnormality, not recognized as a heritable disorder, raises questions about the development of the ischemic or degenerative processes thought important in this disease. Additional family studies of individuals with conduction system disease are needed.