Bilateral bundle branch block. Right bundle branch block associated with left anterior fascicular block.

This report describes the clinical and electrocardiographic features in 30 cases of complete right bundle branch block associated with a block of the anterior fascicle of the left bundle branch, 7 of which also featured a block of the posterior fascicle of the left bundle branch (trifascicular block). The majority of the patients suffered from coronary atherosclerotic heart disease and/or hypertensive heart disease. Complete right bundle branch block associated with fascicular block of the left bundle branch constitutes a special electrocardiographic pattern. The prognosis of the patients presenting this pattern is poor, since it may develop into trifascicular block, i.e., complete atrioventricular block, often necessitating the implantation of artificial pacemakers.