Electrocardiographic abnormalities and risk of developing cardiac events in extracardiac sarcoidosis

Background Cardiac involvement is a leading cause of death from sarcoidosis. Because the efficacy of corticosteroid treatment is limited in patients with cardiac manifestation, early diagnosis is important. However, cardiac involvement is difficult to identify at early stages and is often underdiagnosed. Therefore, this study aimed to identify electrocardiographic risk factors for cardiac events in patients with extracardiac sarcoidosis. Methods This prospective observational cohort study included 227 patients with extracardiac sarcoidosis who did not have any cardiac manifestation (age, 49±17years; women, 63%). We studied the association of electrocardiographic abnormalities with developing cardiac manifestations. Results During a follow-up of 6.3±3.7years, 11 patients developed cardiac events, including advanced atrioventricular block (4 patients), ventricular tachycardia (4 patients), and systolic dysfunction (3 patients). All patients had electrocardiographic abnormalities prior to the development of cardiac events. In multivariate analyses, the baseline heart rate and PR interval were associated with increased risk of developing cardiac events. The QRS duration and corrected QT interval were not associated with cardiac manifestations. The multivariate analyses also revealed that baseline conduction disorder, ST segment/T wave abnormalities, and fragmented QRS complexes were associated with cardiac events. Conclusions Electrocardiographic abnormalities occurred prior to cardiac events in extracardiac sarcoidosis. Patients with electrocardiographic abnormalities may require further evaluation for cardiac involvement and careful follow-up.