Fatal biatrial thrombus in a patient with idiopathic restrictive cardiomyopathy during sinus rhythm

A 55 year-old man was admitted to our hospital because of progressive dyspnea and fatigue. One year earlier, the patient has been diagnosed as having idiopathic restrictive cardiomyopathy. On physical examination the blood pressure was 110/70 mm Hg and the heart rate was regular at 85 beats/min. On admission, jugular venous distention to the angle of the jaw, bilateral basilar rales and trace peripheral edema. Transthoracic echocardiography (TTE) revealed normal sized left and right ventricles. The left and right atriums were enlarged. TTE demonstrated a thrombus within the dilated right atrium. Transesophageal echocardiography confirmed the presence of a thrombus (4.0 × 2.1 cm) in the posterolateral wall of right atrium. Moreover a mobile thrombus (2.0 × 1.4 cm) was detected in the left atrial appendage. Fractional heparin was started to prevent any tromboembolic occurrences during follow up. But, he died due to sudden cardiopulmonary arrest development during follow up. We have reported an extremely rare case of biatrial thrombus developed in a patient with idiopathic restrictive cardiomyopathy during sinus rhythm.