AJR 2004; 183:1838-1839
© American Roentgen Ray Society
Acute Myocardial Infarction as the First Manifestation of Left Atrial Myxoma
David Maintz,
Stefan Gunia,
Peter Baumgart,
Andreas Hoffmeier and
Roman Fischbach
University Hospital Muenster Muenster D-48129, Germany
Clemenshospital Muenster D-48129, Germany
University Hospital Muenster Muenster D-48129, Germany
A 39-year-old female patient had an acute episode of severe retrosternal
chest pain during sexual intercourse. Physical examination and ECG findings
were unremarkable. The patient's increased total creatine kinase level of 525
U/L (creatine kinase isoenzyme, 38 U/L) suggested myocardial infarction.
Echocardiography showed a left atrial mass, diagnosed as most likely a
myxoma. Catheter angiography revealed unremarkable coronary arteries with no
signs of stenotic or occlusive disease. Cardiac MRI was performed to assess
the cardiac mass and to investigate a possible myocardial infarction.
Short-axis and four-chamber views from cine-balanced fast-field-echo pulse
sequences showed a mass of intermediate signal intensity in the left atrial
attached to the interatrial septum (Fig.
2A). During diastole, a prolapse of the mass through the mitral
valve was visible, and mitral inflow was partially obstructed. The surface of
the mass was irregular with lobulations and furrows. Cine images also showed a
circumscribed wall-motion abnormality in the midventricular septum with
akinesia and loss of systolic wall thickening. MRI perfusion images showed
weak contrast enhancement of the tumor and a circumscribed small perfusion
defect in the mid interventricular septum
(Fig. 2B). This area of the
septum showed a bright signal enhancement on T1-weighted inversion recovery
images obtained 15 min after IV injection of gadopentetate dimeglumine
representing a small myocardial infarction
(Fig. 2C).
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Fig. 2A. —39-year-old woman presenting with acute myocardial
infarction. Four-chamber image from ECG-gated breath-hold cine-balanced
fast-field-echo pulse sequence shows intraatrial myxoma (arrow) with
attachment to septum and villous surface. RA = right atrial cavity, RV = right
ventricular cavity, LV = left ventricular cavity.
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Fig. 2B. —39-year-old woman presenting with acute myocardial
infarction. Gradient-echo MR perfusion image shows circumscribed small
perfusion defect in interventricular septum (arrow). LV = left
ventricular cavity.
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Fig. 2C. —39-year-old woman presenting with acute myocardial
infarction. Gadolinium-enhanced T1-weighted (late enhancement) inversion
recovery cardiac image shows circumscribed enhancement (arrow) of
small myocardial infarction in interventricular septum. RV = right ventricular
cavity, LV = left ventricular cavity.
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The absence of cardiovascular risk factors, the normal findings on catheter
angiography, and the lobulated surface of the left atrial myxoma were highly
suggestive of an embolic origin for the infarct—a thrombus that
disengaged from the tumor surface. Late enhancement MRI is known to be a
sensitive and accurate technique for determination of infarct dimensions. As
this case shows, even small infarctions of less than 1 cm can be detected with
this technique. The cardiac tumor was confirmed as a myxoma after resection
(Fig. 2D). The patient's
postoperative course was uneventful.
MRI can provide accurate information on the size, location, point of
attachment, and tissue characterization of myxomas. Usually, myxomas exhibit
an inhomogeneous isointense signal on T1-weighted images, a slightly
hyperintense signal on T2-weighted images, and enhancement after IV injection
of gadolinium chelate [1].
Myxomas account for most primary cardiac tumors
[2]. Patients with myxomas most
frequently present with embolism, intracardiac obstruction, constitutional
symptoms, and arrhythmia [3].
Although systemic embolization is common in left atrial myxomas, coronary
artery embolization as a presentation of a myxoma is extremely rare. The low
incidence of coronary embolization may be explained by the perpendicular
position of the coronary ostia in relation to the aortic blood flow and the
protection of the ostia by the aortic leaflets in systole
[4]. Panos et al.
[5] reviewed 26 cases of left
atrial myxoma presenting as myocardial infarction. Catheter coronary
angiography revealed right coronary artery embolization in 47.6% of cases. The
left anterior descending coronary artery accounted for 19%, and the left
circumflex coronary artery accounted for 9.5% of cases. No coronary artery
abnormality was found in 23.8% of the cases.
References
- Grebenc ML, Rosado-de-Christenson ML, Green CE, Burke AP, Galvin
JR. Cardiac myxoma: imaging features in 83 patients.
RadioGraphics2002; 22:673
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- Reynen K. Cardiac myxomas. N Eng J Med1995; 333:1610
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- Pinede L, Pierre D, Loire R. Clinical presentation of left atrial
cardiac myxoma: a series of 112 consecutive cases.
Medicine 2001;80:159
–172[Medline]
- Harikrishnan S, KrishnaManohar SR, Krishna Kumar R, Tharakan JM.
Left atrial myxoma presenting as acute myocardial infarction in a child.
Cardiology2003; 99:55
–56[Medline]
- Panos A, Kalangos A, Sztajzel J. Left atrial myxoma presenting with
myocardial infarction: case report and review of the literature.
Int J Cardiol1997; 62:73
–75[Medline]
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