Right atrial thrombosis as a complication of arrhythmogenic right ventricular cardiomyopathy.

A 65-year-old woman was admitted to our hospital due to palpitation. Electrocardiogram (ECG) showed ventricular tachycardia originating from the right ventricle, and transthoracic echocardiography revealed dilatations of the right atrium and ventricle. The diagnosis of arrhythmogenic right ventricular cardiomyopathy was made. Eleven months later, echocardiography revealed a solid thrombus (36x32 mm) attached to the free wall of the right atrium, and it was surgically resected. Four months after the operation, a solid thrombus (48x30 mm) appeared again at the same site despite anticoagulant treatment. The patient died of both left and right heart failure 33 months after the operation.