Cardiac sarcoidosis as a cause of total atrioventricular block: importance of differential diagnosis

Sarcoidosis is a systemic granulomatous disorder of unknown cause that can affect virtually any organ. The extracardiac forms are usually benign and subjected to spontaneous remission. However, the prognosis may be unfavorable in case of cardiac involvement. Symptomatic cardiac sarcoidosis (CS) is diagnosed in approximately 5% of patients with sarcoidosis. However, based on some autopsy series, the prevalence of subclinical CS can reach 25–30%. Cardiac involvement is mainly characterized by compact non-caseous epithelioid cell granulomas that, depending on their extent and location, can lead to heart failure (HF) or cause potentially lethal arrhythmias, particularly ventricular, such as ventricular tachycardia (VT) and ventricular fibrillation (VF), and atrioventricular (AV) conduction disorders. The etiological diagnosis of CS can be of extreme clinical importance, especially in cases of advanced AV block (AVB), changing therapeutic measures and presenting significant prognostic implications. (author)