CLINICAL AND ELECTROCARDIOGRAPHIC CHARACT ERISTICS OF MASQUERADING BUNDLE-BRANCH BLOCK

Introduction. Masquerading bundle branch block is a right bundle branc h block with a left anterior hemiblock which appears similar to a left bundle branch block in the frontal plane leads. Material and methods. We have followed 22 patients with such a pattern in the electrocardio gram for 3 years. Results. Thirteen patients (59%) developed high degr ee atrioventricular block. During this period, there were 4 deaths, 3 from heart failure and 1 due to sepsis. Conclusions. We conclude that progression to high degree atrioventricular block is quite common in t he presence of this kind of branch block. It is frequently associated to advanced heart failure, so the prognosis is usually poor.