Malignant presentation of cardiac hemangioma: a rare cause of complete atrioventricular block.

A 46-year-old woman suffered effort intolerance for months. She had been healthy in the past, without systemic diseases. She had experienced near-syncope before arrival at our center. On admission, her physical examination was unremarkable. ECG exhibited normal sinus rhythm, P pulmonale, and first-degree atrioventricular (AV) block. A transthoracic echocardiogram demonstrated a huge right atrial (RA) mass, 7.98 5.70 cm in size, with 23 mm Hg of transvalvular pressure gradient. The global ventricular contractility was normal (Data Supplement Movies I and II). These findings were confirmed by 3-dimensional echocardiography (Figure 1; Data Supplement Movies III and IV). Cardiac magnetic resonance imaging showed a large, well-defined intracavity mass on T1-weighted image. After contrast injection, delayed images revealed a strong signal indicating hypervascularity (Figure 2 and onlineonly Data Supplement), highly suggestive of hemangioma, angioma, or angiosarcoma. Coronary angiography failed to locate the feeding artery, but RA and right ventricular angiography showed a large space occupied by the lesion (Figure 3). The patient had an episode of syncope on her second day of stay. ECG showed complete AV block and junctional escape rhythm with a ventricular rate of 50/min (Figure 4). She received emergency surgical intervention for complete excision of the RA tumor (Figure 5). Cardiac function recovered promptly after surgery. A temporary epicardial pacemaker was used initially, but because of persistent complete AV block, a permanent pacemaker subsequently was implanted. The patient was discharged uneventfully 9 days after the operation. She has been followed up for 6 months without any echocardiographic evidence of recurrence. On retrospective analysis of the patient’s data, we noticed that her ECG taken in September 2004 had a first-degree AV block with a PR interval of 0.24 second. In May 2007, the PR interval was found to be prolonged (0.32 second), and a 24-hour Holter depicted asymptomatic intermittent complete AV block. By June 2007, symptomatic bradycardia had developed. Thus, progression of AV block took at least 3 years. Hemangiomas of the heart are benign by cell type but can have serious consequences.1 RA hemangioma on interatrial septum is typically silent,2 but the location and gross appearance of our case mimicked a mesothelioma of the AV node. Mesotheliomas of the AV node are well known to cause heart block and sudden death.3 Thus, the finding of complete heart block and syncope in our patient suggests that hemangiomas are not always clinically benign if located in areas of cardiac conduction systems. To the best of our knowledge, this is the first case of RA hemangioma to demonstrate complete AV block.