Ann Thorac Surg 2005;79:1392-1393
© 2005 The Society of Thoracic Surgeons
Case report
Left Atrial Appendage Aneurysm
Alok Mathur, MCha,
Kenton J. Zehr, MD*,a,
Lawrence J. Sinak, MDa,
Robert F. Rea, MDa
a Division of Cardiovascular Surgery, Mayo Clinic, Rochester, Minnesota, USA
Accepted for publication October 2, 2003.
* Address reprint requests to Dr Zehr, Division of Cardiovascular Surgery, Mayo Clinic, 200 First St, SW, Rochester, MN, USA 55905
zehr.kenton{at}mayo.edu
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Abstract
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Aneurysms of the left atrial appendage are exceedingly rare. Patients most commonly present with atrial tachyarrhythmias and thromboembolism. Resection of the aneurysm is usually curative. We present a case report of a 60-year-old female with a long-standing history of atrial arrhythmias found to have a large left atrial appendage aneurysm with additional bi-atrial enlargement and a family history of atrial arrhythmias. The patient was successfully treated with resection of the aneurysm and a Cox-Maze III procedure.
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Introduction
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Left atrial appendage aneurysms are exceedingly rare. They are caused by congenital dysplasia of the atrial muscle. Patients present with atrial tachyarrhythmias due to ectopic foci of atrial rhythm generation or systemic thromboembolism due to sluggish blood flow in the recesses of the aneurysm. Surgical excision addresses the thromboembolism issue. Excision of the appendage alone has been reported as sufficient in eliminating the atrial tachyarrhythmias.
A 60-year-old female presented to our institution for treatment of atrial arrhythmias. She first had atrial arrhythmias develop after knee surgery 2 years prior. In the intervening 2 years, she had multiple episodes of atrial flutter and atrial fibrillation. She had been admitted to the hospital in congestive heart failure secondary to rapidly conducted atrial fibrillation. She was treated with a variety of antiarrhythmics. Ultimately her rhythm was controlled on amiodarone. Subsequently she had neuro-toxicity develop that was related to chronic amiodarone therapy. She was anticoagulated for prophylaxis against thromboembolism. She had a previous electrophysiologic study showing inducible nonsustained atrial foci of dysrhythmia arising from both the left and the right atrium, which quickly degenerated into atrial fibrillation.
She had a family history of cardiac arrhythmias. Her father had a sudden death at an age of 65, which was suspicious for an arrhythmia. Three of her brothers had a history of atrial arrhythmias in the absence of left atrial appendage aneurysms. One brother had undergone radiofrequency ablation.
On presentation, she had a regular heart rate and an unremarkable clinical examination except for some tremors in her hands thought to be related to amiodarone side effects. Electrocardiogram confirmed a normal sinus rhythm and left atrial enlargement. Chest roentgenogram showed some cardiomegaly and evidence of pulmonary venous hypertension.
She underwent a transthoracic and a transesophageal echocardiogram, which demonstrated a 7 x 5 x 3.5 cm left atrial appendage aneurysm and a bi-atrial enlargement (Fig 1). Her left ventricular function and cardiac valves were normal. She underwent a standard Cox-Maze III procedure and excision of the left atrial appendage aneurysm.

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Fig 1. Transesophageal echocardiogram showing transverse view at the level of the aortic root showing aneurysmal left atrial appendage. (Ao = aortic root; LA = left atrium; LAA = left atrial appendage; PA = pulmonary artery.)
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Her postoperative course was uneventful, and she returned to a stable sinus rhythm with first degree heart block after surgery. However, she did have recurring atrial tachyarrhythmias 1 week postoperatively and was treated with propafenone. Seven weeks postoperatively, she returned to normal sinus rhythm with right bundle and left anterior fascicular block. The propafenone was discontinued. She continues to be in stable sinus rhythm at her 1-year follow-up with no antiarrhythmics.
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Comment
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Left atrial appendage aneurysms are uncommon. They are usually congenital but may be acquired. If acquired, they are associated with left atrial enlargement secondary to mitral valve disease [1]. If congenital, they usually present in the second or third decade of life and the presenting symptoms are palpitations secondary to atrial arrhythmias as well as dyspnea and chest pain [2, 3]. Our patient had an unusually late presentation. She was distressed by the side effects of amiodarone and preferred to discontinue her oral anticoagulation.
Echocardiography is usually diagnostic. Magnetic resonance imaging has been reported to aid in diagnosis [4]. Morphologically, the origin of the aneurysm has been attributed to congenital dysplasia of musculi pectinati [5]. Treatment of this entity has traditionally been aneurysmectomy [6, 7] with or without cardiopulmonary bypass [8].However, there are no long-term follow-up studies on these patients. Our patient had bi-atrial enlargement in addition to the aneurysm. It was thought prudent to perform a maze procedure in view of the presentation with atrial fibrillation as well as more organized atrial flutter like arrhythmias. Arguably, excision of the left atrial appendage aneurysm alone has a good chance of keeping such patients free of new fibrillatory atrial arrhythmias if the substrate for ectopic foci is fully resected. Freedom from atrial arrhythmias has been reported from 6 months to 8 years after aneurysmectomy [3, 57]. We chose to perform an adjunctive Cox-Maze procedure as a prior electrophysiologic study showed inducible abnormal foci in both atria. The patient had enlarged atria as well. The soundness of the decision was confirmed by her postoperative electrocardiogram history (Figs 2, 3). Our patient had a recurrence of her atrial tachyarrhythmias 1 week after surgery that was treated briefly with propafenone. However, after her Cox-Maze III incisions healed, she is now in normal sinus rhythm and free from medication at 1 year postoperatively. This evidence supports the hypothesis that the focus of the arrhythmia may not always be the left atrial appendage aneurysm. Indeed, the base of the left atrial appendage aneurysm has been reported to be up to 7 cm in diameter [6]. A mere resection of an aneurysm in this case may leave enough dysmorphic tissue to propagate atrial fibrillation. At our center, the maze procedure has been performed with no significant increase in morbidity or mortality for the patient and with high rates of conversion to sinus rhythm, although with a small probability of heart block [9]. At centers that do not perform these procedures routinely, excision of the appendage aneurysm alone appears to be a reasonable choice.

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Fig 2. Postoperative twelve-lead electrocardiogram showing an atrial tachycardia with a 2:1 atrioventricular conduction.
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Fig 3. Postoperative three-lead rhythm strip showing atrial tachycardia and atrial flutter with variable atrioventricular conduction.
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References
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- Gold JP, Afifi HY, Ko W, Horner N, Hahn R. Congential giant aneurysms of the left atrial appendage: diagnosis and management. J Card Surg. 1996;11(2):147150[Medline]
- Pomerantzeff PM, Freyre HM, de Almeida Brandao CM, Pereira Barreto AC, de Oliveira AS. Aneurysm of the left atrial appendage. Ann Thorac Surg. 2002;73:19811983[Abstract/Free Full Text]
- Wagshal AB, Applebaum A, Crystal P, et al. Atrial tachycardia as the presenting sign of a left atrial appendage aneurysm. Pacing Clin Electrophysiol. 2000;23(2):283285[Medline]
- Hoffmann U, Hamed N, Herold C, Globits S. Radiological signs of a left atrial aneurysm. Eur Radiol. 2000;10(8):13321334[Medline]
- Victor S, Nayak VM. Aneurysm of the left atrial appendage. Texas Heart Inst J. 2001;28(2):111118[Medline]
- Zhao J, Ge Y, Yan H, Pan Y, Liao Y. Treatment of congenital aneurysms of the left atrium and left atrial appendage. Tex Heart Inst J. 1999;26(2):136139[Medline]
- Pome G, Pelenghi S, Grassi M, Vignati G, Pellegrini A. Congenital intrapericardial aneurysm of the left atrial appendage. Ann Thorac Surg. 2000;69:15691571[Abstract/Free Full Text]
- Burke RP, Mark JB, Collins JJ Jr, et al. Improved surgical approach to left atrial appendage aneurysm. J Card Surg. 1992;7:104107[Medline]
- Schaff HV, Dearani JA, Daly RC, Orszulak TA, Danielson GK. Cox-Maze procedure for atrial fibrillation: Mayo Clinic experience. Semin Thorac Cardiovasc Surg. 2000;12(1):3037[Medline]
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