Intramyocardial hematoma causing cardiac tamponade after repair of Ebstein malformation: erroneous echocardiographic diagnosis as intracavitary thrombus.

Intramyocardial hematoma is an uncommon lesion, most often occurring after chest trauma, aortic valve disease, acute myocardial infarction, or coronary artery bypass surgery. We describe a 17-year-old patient who experienced cardiac tamponade after repair of Ebstein malformation. The malformation was caused by an enlarging intramyocardial hematoma that extended from the right atrium to the atrialized right ventricle. The hematoma was incorrectly diagnosed by echocardiography as an intracavitary thrombus, and the correct diagnosis was recognized only at the time of surgical intervention.