Cardiac Sarcoidosis

Sarcoidosis is a multisystem granulomatous disorder resulting from a combination of environmental, genetic, and inflammatory factors causing the accumulation of noncaseating granulomas in many organs, such as the lungs, eyes, skin, lymph nodes, and heart. Cardiac sarcoidosis (CS) refers to granulomatous inflammation that affects the heart in isolation or as part of systemic sarcoidosis. Based on imaging and autopsy findings, CS occurs in approximately 25% of patients with sarcoidosis. Cardiac sarcoidosis is a rare condition with a generally poor prognosis. The diagnosis of CS is often difficult. Sarcoidosis is sometimes considered a diagnosis of exclusion because there is no single diagnostic laboratory, radiologic, or other test. The clinical presentation of sarcoidosis, generally and CS particularly, is highly variable. Cardiac sarcoidosis may present with symptoms of heart failure, sudden cardiac death, ventricular arrhythmia, myocardial infarction, or atrioventricular (AV) block; the most common presentations are conduction system disorders and heart failure. Systemic clinical manifestations of sarcoidosis include signs and symptoms of other organ involvement, such as ocular, neurological, and cutaneous sarcoid. Approximately 25% of patients have isolated cardiac sarcoidosis without systemic involvement, and it is debatable if the prognosis differs from systemic sarcoidosis with cardiac manifestations. The most important prognostic indicator in patients with CS is left ventricle ejection fraction (LVEF). Endomyocardial biopsy, an invasive procedure, has a low diagnostic yield due to the patchy involvement of the myocardium. Therefore, advanced imaging studies are employed to enhance the accuracy of diagnosis, particularly in patients without extracardiac manifestations of sarcoidosis.