Anomalous Origin of the Left Coronary Artery from the Pulmonary Artery (ALCAPA) Presenting as a Complete Heart Block

A 51-year-old previously asymptomatic man presented with complete heart block (CHB). During pacemaker implantation, fluoroscopy showed a peculiar pattern of cardiac calcification. Coronary angiography, performed to determine the origin of calcification, demonstrated an anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA). A left ventriculogram showed normal ventricular contraction. Echocardiography demonstrated normal systolic function without any regional wall motion abnormality. The endocardium of the mid and basal portions of the anteroseptal, anterior and anterolateral walls as well as both of the papillary muscles were calcified. Specifically noted was a calcific bar extending across the base of the interventricular septum (IVS) on both the echocardiogram and the left ventricle angiogram. The development of CHB in the absence of transmural myocardial infarction is intriguing. It is likely that endocardial fibroelastosis during infancy led to endocardial fibrosis and scarring subsequent calcium deposition. Extension of this calcification into the conduction system may have led to CHB. This is the first report of an adult patient with ALCAPA presenting with CHB.