Outcome of Cardiac Sarcoidosis Presenting With High-Grade Atrioventricular Block

Background: Symptomatic high-grade atrioventricular block (AVB) is the most common and often the only presenting manifestation (lone AVB) of cardiac sarcoidosis. Implantation of an intracardiac cardioverter defibrillator instead of a pacemaker is recommended, but the true risk of fatal arrhythmia, one incident to lone AVB in particular, remains poorly known. Methods: We used Myocardial Inflammatory Diseases in Finland Study Group Registry to analyze the presentations, left ventricular (LV) function, pacemaker therapy, and ventricular arrhythmias in cardiac sarcoidosis. From year 1988 to 2015, altogether 325 cases of cardiac sarcoidosis were diagnosed in Finland. Of them, 143 patients (112 women, mean age 52 years) presented with Mobitz II second degree or third degree AVB in the absence of other explanatory cardiac disease. Results: Concomitant with AVB at presentation, 20 patients had either ventricular tachycardia or severe LV dysfunction with ejection fraction <35% and 29 patients had nonsevere LV dysf...