Abstract Background: Pericardial effusion is a relatively common finding and can progress to cardiac tamponade; etiological diagnosis is important for guiding treatment decisions. With advances in medicine and improvement in the social context, the most frequent etiological causes have changed. Objectives: To evaluate the clinical and laboratory characteristics, etiology, and clinical course of patients with pericardial effusion and cardiac tamponade. Materials and methods: Patients with pericardial effusion classified as small (< 10 mm), moderate (between 10-20 mm), or severe (> […]