A case of restrictive cardiomyopathy complicated by recurrent pulmonary thromboembolism originating at the right atrial appendage.

Idiopathic restrictive cardiomyopathy (RCM) is rare, and its natural history is not well known. Its prognosis in infants is extremely poor, whereas patients with RCM occurring in middle age have comparatively good prognoses. Here, we report a case of idiopathic RCM with the disease onset at 10 years old. Echocardiography and cardiac catheterization revealed a biventricular restrictive pattern; however, the right ventricle showed more severe restriction. At 20 years old, severe pulmonary thromboembolism (PTE) occurred with circulatory collapse. The right atrium was extremely enlarged and the appendage was filled with moderate thrombi that migrated to pulmonary arteries. PTE is a rare complication of idiopathic RCM; however, this complication occurs more commonly in other secondary RCMs. In patients with restrictive hemodynamic pattern, the presence of thrombi in cardiac cavities should be routinely examined. <Learning objective: A patient with idiopathic restrictive cardiomyopathy, with disease onset at 10 years old, is described. Echocardiography and cardiac catheterization revealed biventricular restrictive pattern, however right ventricle showed more severe restriction. At 20 years old, he had severe pulmonary thromboembolism. The right atrial appendage was filled with moderate thrombi that migrated to pulmonary arteries. The right atrium should be assessed to determine the presence of thrombi in patients with restrictive hemodynamic pattern.>.