Clinical features and significance of bifascicular block progressed to complete atrioventricular block *
We studied the clinical features of four male patients in whom bifascicular block (right bundle branch block with left anterior fascicular block) progressed to complete atrioventricular block. A history of long-standing hypertension in all of these patients and congestive heart failure in two of them was present. A 12-lead electrocardiogram prior to developement of the heart block revealed a normal PQ interval in all the patients. Syncope was an initial symptom of the heart block in three of the patients. From various clinical data, the cause of the fascicular block was thought to be degeneration and/or fibrosis of the conduction system of the heart. A DDD pacemaker was successfully implanted in two patients and a VVI pacemaker in the other two. Although the incidence of the progression to heart block is thought lo be relatively low, close observation and follow-up are necessary because of the high molality due to serious underlying heart diseases in patients with a bifascicular block. The clinical features and significance of bifascicular block were discussed in detail. (Accepted on August 17, 1998) Kawasaki Igakkaishi 24 (2) : 71 - 76. 1998
