MULTIFASCICULAR BLOCK IN CARDIOMYOPATHY - INCIDENCE, LOCALIZATION BY HIS-BUNDLE STUDY AND PROGNOSIS

In 70 patients with cardiomyopathy 9 (13%) had bifascicular block: right bundle branch block with left anterior hemiblock in 4, right bundle branch block with left posterior hemiblock in 2 and left bundle branch block with left anterior hemiblock in 3. Isolated left bundle branch block was present in 4, isolated left anterior hemiblock in 13 and isolated left posterior hemiblock in 1. No isolated right bundle branch block was found. Five of the patients with bifascicular block were evaluated by His bundle electrocardiography and atrial pacing. Block in the His-Purkinje system (prolonged HV internal) was present in 4 and atrioventricular conduction (AH interval) was normal in all 5. Despite a common prolongation in intraventricular conduction short term prognosis seems to be favorable since none had spontaneous progression to more advanced block or experienced Stokes-Adams attacks for an average follow-up period of at least 42 mo. and with atrial packing, one-to-one AH interval persisted to rates up to 150/min in all patients with no further prolongation of HV interval.