A Blast From the Past: Radiation Therapy During Childhood Causing Cardiac Fibrosis and Calcification Leading to Complete Heart Block.

Complete heart block (CHB) in a young patient is a rare phenomenon necessitating an extensive workup to identify the etiology of conduction disturbance. Radiotherapy of the thorax is a known risk factor for cardiomyopathy; however, CHB is a rare complication. Here we present a case of a 46-year-old man who presented with CHB and was found to have significant cardiac fibrosis and calcification of the mitral valve annulus. His management required a multidisciplinary and multimodality approach to be able to identify childhood radiation as the cause of cardiomyopathy and establish a personalized management strategy with cardiac resynchronization therapy defibrillator. This case highlights radiation therapy as an important cause of cardiac conduction abnormalities even decades later, and the importance of extensive search for other reversible etiologies using the multimodality approach.