Ann Thorac Surg 2001;71:1014-1016
© 2001 The Society of Thoracic Surgeons
Case report
Giant left atrial intrapericardial aneurysm: noninvasive preoperative imaging
Dongfang Wang, MD, PhDa,b,
Bridget Holden, MDb,
Clare Savage, MDb,
Kailun Zhang, MDa,
Joseph B. Zwischenberger, MDb
a Department of Cardiovascular Surgery, Institute of Cardiovascular Diseases of Tongji Medical University, Wuhan, China
b Department of Surgery, The University of Texas Medical Branch, Galveston, Texas, USA
Accepted for publication September 7, 2000.
Address reprint requests to Dr Zwischenberger, Division of Cardiothoracic Surgery, The University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555-0528
e-mail: jzwische{at}utmb.edu
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Abstract
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Congenital giant intrapericardial aneurysms of the left atrium are rare. A 17-year-old boy presented with paroxysmal episodes of palpitations, chest pain, and dyspnea. A chest roentgenogram showed an enlarged left cardiac silhouette. Transthoracic echocardiography imaging showed an intrapericardial aneurysm of the left atrium. Cardiac magnetic resonance imaging confirmed the diagnosis and delineated adjacent structures to plan the surgical resection. We have found no previous reports of cases of diagnosis and preoperative assessment based solely on noninvasive imaging.
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Introduction
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Intrapericardial aneurysm of the left atrium or atrial appendage without mitral disease is usually asymptomatic, appearing on a routine chest roentgenogram as an enlarged cardiac silhouette. Surgical excision is indicated even in asymptomatic patients because of potentially life-threatening complications including arrhythmias, systemic thromboemboli, and congestive heart failure.
A 17-year-old boy presented with paroxysmal episodes of palpitations, chest pain, and dyspnea over 3 weeks. An electrocardiogram during one episode showed supraventricular tachyarrhythmia. A chest roentgenogram revealed an enlarged left cardiac border. A lateral chest roentgenogram showed a posteriorly displaced esophagus. Transthoracic echocardiography showed an echo-free silhouette (10 x 7–cm) posterior to and communicating with the left atrium. Color-flow Doppler demonstrated blood flow between the left atrium and the echo-free structure without evidence of mitral valve stenosis or regurgitation. Cardiac magnetic resonance imaging (MRI) showed an 8 x 12–cm aneurysm of the left atrial appendage (Figs 1 and 2) compressing the left ventricle.
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Fig 1. Magnetic resonance image showing communication between the left atrium and the aneurysm, compressing the left ventricle. (Aneu = aneurysm; LA = left atrium; LV = left ventricle.)
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Fig 2. Magnetic resonance image showing 8 x 12–cm left atrial intrapericardial aneurysm. (Aneu = aneurysm.)
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Median sternotomy with bicaval cardiopulmonary bypass (CPB) revealed a giant aneurysm (15 x 12 x 10–cm) protruding from the left atrial appendage into the pericardial sac. The pericardium was intact and no other cardiac anomalies were noted. The aneurysm neck (5.5 cm) was located 1.0 cm from the circumflex branch of the left coronary artery, allowing adequate tissue for primary closure. The aneurysm was excised and the defect oversewn. Regular sinus rhythm was restored after aortic unclamping and the patient was weaned from CPB without complications. Pathologic examination showed no evidence of thrombi. The patient has been asymptomatic during 18 months of follow-up.
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Comment
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Congenital aneurysms of the left atrium can be extrapericardial or intrapericardial [1]. The more common extrapericardial aneurysm results from extrusion of the atrial wall or appendage through a pericardial defect [1]. Intrapericardial aneurysms arising from a congenital weakness in the atrial wall [2] are more rare and are usually asymptomatic until the second to the fourth decade [1]. Diagnosis of an intrapericardial aneurysm requires fulfillment of the following criteria: (1) normal left atrium; (2) direct continuity with blood flow through the left atrium; and (3) intact pericardium [3]. Although confirmation of an intact pericardium can be made only during surgery or autopsy, distortion of the left ventricle seen with presurgical imaging studies suggests an intrapericardial aneurysm. In our case MRI clearly showed the mass effect of a giant aneurysm compressing and displacing the left ventricle within the pericardial sac.
Symptoms include supraventricular arrhythmias, chest pain, or systemic thromboemboli. Supraventricular arrhythmias including atrial fibrillation, atrial flutter, and paroxysmal atrial tachycardia are most frequently seen. Less commonly patients present with congestive heart failure or cerebral embolism [2].
The initial imaging study is a chest roentgenogram, typically showing nonspecific cardiomegaly or an enlarged left cardiac silhouette. The differential diagnosis includes cardiac, pericardial and mediastinal cysts or tumors, enlarged coronary sinus, and mitral valve disease with left atrial dilation. Transthoracic echocardiography including two-dimensional imaging and color and pulsed-wave Doppler is the most useful noninvasive means of study, typically showing an echo-free area connected to the left atrium. Color-flow Doppler confirms blood flow between the aneurysm and left atrium, elucidating the aneurysm neck and the presence of thrombi [4]. Some advocate transesophageal echocardiography if transthoracic images are inadequate for complete pericardial evaluation or to rule out a thrombus; however, transesophageal echocardiography is more invasive and carries a small theoretical risk of aneurysmal rupture and embolization. In our case, the patient’s thin body habitus allowed excellent echogenic windows for transthoracic echocardiography, making transesophageal imaging unnecessary.
We used cardiac MRI to confirm the diagnosis, to rule out thrombi, and to establish the relationship of the aneurysm to adjacent structures such as the pulmonary veins [1]. Cardiac catheterization should be reserved for patients with concomitant cardiac disease or for cases in which echocardiography or MRI findings are inconclusive. Although transseptal left atrial angiography can confirm the diagnosis if the aneurysm cavity opacifies [5], case reports have noted false-negative angiograms [2, 4]. Because the aneurysm fills slowly and simultaneously with the left ventricle, significant dilution of the contrast medium makes left atrial and ventricular aneurysms difficult to image [6]. Furthermore, a thrombus within the aneurysm may obliterate the lumen. Angiography may even dislodge a thrombus, causing systemic embolization, or may induce atrial tachyarrhythmias [2, 3].
Both left thoracotomy and median sternotomy, with or without CPB, are accepted approaches for surgical excision. We prefer median sternotomy for exposure and CPB with cardioplegic arrest for resection of the aneurysm in a motionless field, thus decreasing the risk of embolization during manipulation. We especially recommend this technique when left atrial thrombi are known or when the neck of the aneurysm is broad, as in our case. After surgical excision long-term prognosis is excellent.
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References
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Sigfusson G., Park S.C., Ettedgui J.A., Newman B., Siewers R.D., Neches W.H. Intrapericardial left atrial aneurysm: noninvasive diagnosis. Pediatr Cardiol 1997;18:240-243.[Medline]
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Bramlet D.A., Edwards J.E. Congenital aneurysm of left atrial appendage. Br Heart J 1981;45:97-100.[Abstract/Free Full Text]
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Foale R.A., Gibson T.C., Guyer D.E., Gillam L., King M.E., Weyman A.E. Congenital aneurysms of the left atrium: recognition by cross-sectional echocardiography. Circulation 1982;66:1065-1069.[Abstract/Free Full Text]
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Vargas-Barron J., Sanchez-Ugarte T., Keirns C., Vazquez-Sanchez J., Fernandez-Vasquez F., Barragan R. The differential diagnosis of partial absence of left pericardium and congenital left atrial aneurysm. Am Heart J 1989;118:1348-1350.[Medline]
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Godwin T.F., Auger P., Key J.A., Wigle E.D. Intrapericardial aneurysmal dilation of the left atrial appendage. Circulation 1968;37:397-401.[Abstract/Free Full Text]
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Robinson P.J., Neutze J.M., Brandt P.W., Hill D.G., Anderson R.J., Rutland M.D. Congenital aneurysm of the left atrium: diagnosis and management. Aust New Zealand J Med 1984;14:267-269.
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Abstract
Introduction
