Background and Objectives: pericardial effusion is characterized by the accumulation of excessive fluid in the pericardial space, which can lead to cardiac dysfunction or death. Most of the previous studies have been performed in developed countries and its epidemiologic aspects in developing countries were not well-recognized. The aim of this research was determination of etiology, clinical and paraclinical findings in patients with pericardial effusion.

  Methods: This was a cross-sectional, descriptive and retrospective study. From all of the patients admitted to Buali hospital between 2001 to 2003 ,49 patients that showed moderate to massive pericardial effusion in echocardiography were selected and studied in terms of history, physical examination, CXR, ECG and pericardial fluid analysis (if performed).

  Results: From 49 patients 25 (51%) were female and 24 were male. Age ranges of patients were 11 to 85 years. The age of 42% of the patients was above 60 years. The most common clinical complaints were dyspnea (44.9%) and chest pain (24.5%). ECG in most of them (53.1%) were normal sinus rhythm. Cardiac electrical axis in 83.7 % was normal, but ECG in 83.7% of cases showed low voltage QRS complex. The most common findings in CXR was cardiomegaly (85.7%) and 14.3% of patients had normal CXR. Common etiologies of pericardial effusion were chronic renal failure (16.3%), tuberculosis (8.2%), heart failure (8.2%) and malignancies (6.1%). Etiology of disease in 44.8% of patients was unknown.

  Conclusion: It seems that most of pericardial effusions occur in higher ages. It can be due to high prevalence of different diseases such as heart failure, chronic renal failure or malignancies in senile persons.