Type I Second Degree Atrioventricular Block in a Woman With Remote Repair of a Ventricular Septal Defect.

In a 45-year-old woman with syncope, an electrocardiogram revealed intermittent asymptomatic type I second degree atrioventricular block, right bundle branch block and left anterior fascicular block. An echocardiogram documented concentric left ventricular hypertrophy and right ventricular dilatation and hypokinesia. Because the patient did not have second degree atrioventricular block at the time of an electrophysiological study, the atrioventricular node, the left posterior fascicle, and the His bundle all remain potential sites for the type I second degree atrioventricular block on her initial electrocardiogram.