Childhood Problem Flares at Age 50

ANSWER
The correct interpretation includes normal sinus rhythm, right bundle branch block, and left anterior fascicular block. Normal sinus rhythm is evidenced by a rate between 60 and 100 beats/min, with a corresponding P for every QRS and a QRS for every P.

Right bundle branch block is evidenced by a QRS duration > 120 ms, a terminal broad S wave in lead I, and an RSR’ complex in lead V₁. Left anterior fascicular block is evident from the finding that the S waves are greater than the R waves in leads II, III, and aVF.

The presence of a right ventricular block and left anterior fascicular block (bifascicular block) is consistent with a history of a VSD and/or surgical repair. The right and left bundles proceed from the atrioventricular node and bundle of His down the ventricular septum to the Purkinje fibers in the distal ventricular myocardium. Therefore, congenital anomalies of the ventricular septum, and/or surgical intervention within it, often affect conduction of the right and/or left bundle.

This patient’s symptoms were a result of his dilated aorta, and he underwent successful repair, with resolution of his symptoms.