Left atrial intramural hematoma after resection of myxoma: report of a case.

A 73-year-old woman was referred for treatment of left atrial (LA) myxoma. At surgery, a myxoma was attached to the left atrial side of the fossa ovalis in the atrial septum by a stalk and was transmurally excised with a margin of the atrial septum. The atrial septum was closed without any prosthetic materials under mild to moderate tension. Although she was asymptomatic, postoperative transesophageal echocardiography (TEE) revealed an abnormal cavity, containing heterogeneous echogenesity without blood flow, in the posterior LA wall. Magnetic resonance imaging (MRI) demonstrated a mass without significant enhancement. It was considered to be an intramural hematoma, and the diagnosis of LA dissection was made. Follow-up echocardiography showed disappearance of the dissected lumen without surgical intervention. Both TEE and MRI are useful for the correct diagnosis of an LA dissection; and surgical intervention, entry closure or internal drainage, may not always be necessary in the absence of a hemodynamic compromise with an LA dissection.