Atrial Myxoma That Mimics Mitral Stenosis

September 14, 2005
Waqas Ahmed, MD
Waqas Ahmed, MD

,
T. Michael Fan, MD
T. Michael Fan, MD

For 2 years, a 60-year-old woman with long-standing hypertension had experienced worsening dizzy spells, fatigue, and chest discomfort. She also had cold extremities, significant dyspnea on exertion, and orthopnea. The patient was taking amlodipine and furosemide.

For 2 years, a 60-year-old woman with long-standing hypertension had experienced worsening dizzy spells, fatigue, and chest discomfort. She also had cold extremities, significant dyspnea on exertion, and orthopnea. The patient was taking amlodipine and furosemide.

A loud, split first heart sound was audible with a soft 1/6 systolic murmur over the right sternal border; a 2/6 diastolic rumble was loudest at the apex. No opening snap was noted. A transthoracic echocardiogram revealed an 8 × 4.5-cm, football-shaped, echogenic mass that filled the left atrium (A, arrow; with mitral valve in closed position). A transesophageal echocardiogram showed the mass was attached to the atrial septum, causing a “tenting” of the atrial septum (B, arrow).

During diastole, the mass protruded into the left ventricle (B, arrowhead; with mitral valve in open position) and produced a functional mitral stenosis; the Doppler mitral inflow pattern showed an elevated mean diastolic gradient of 8 mm Hg. Mitral valve area calculated by pressure half-time was 1.5 cm2. These findings suggested an atrial myxoma.

An 8 × 4 × 4-cm pedunculated mass was resected from the atrial septum. Pathologic examination confirmed a cardiac myxoma.

Drs Waqas Ahmed and T. Michael Fan of the University of South Alabama Medical Center, Mobile, write that myxomas are the most common primary cardiac tumors; they constitute nearly 50% of benign tumors of the heart. Approximately 75% of these lesions are found in the left atrium, where they usually are attached to the fossa ovalis.1 They generally cause classic cardiac symptoms, such as dyspnea on exertion, orthopnea, palpitations, chest pain, fatigue, and peripheral edema.

Myxomas apparently grow rapidly and, in some cases, can cause a variety of constitutional symptoms, including fever, anemia, Raynaud phenomenon, and weight loss.2 Consider this condition in the differential diagnosis of any patient who presents with this constellation of symptoms.

If an atrial myxoma recurs-which is rare-it generally develops within the first few years after surgical removal. Follow-up echocardiography is warranted for patients with recurrent symptoms.3

Four days after surgery, the patient was discharged from the hospital in good condition. Amlodipine was continued. She was doing well at the 2-year follow-up visit.

REFERENCES:1. Reynen K. Cardiac myxomas. N Engl J Med. 1995;333:1610-1617.
2. Seino Y, Ikeda U, Shimada K. Increased expression of interleukin 6 mRNA in cardiac myxomas. Br Heart J. 1993;69:565-567.
3. Cleveland DC, Westaby S, Karp RB. Treatment of intra-atrial cardiac tumors. JAMA. 1983;249:2799-2802.