Ann Thorac Surg 2002;74:251-253
© 2002 The Society of Thoracic Surgeons
Case report
Maze procedure and cor triatriatum repair
Hiroyuki Nakajima, MDa,
Junjiro Kobayashi, MD*a,
Takashi Kurita, MDb,
Soichiro Kitamura, MDa
a Departments of Cardiovascular Surgery,National Cardiovascular Center, Osaka, Japan
b Department of Cardiology, National Cardiovascular Center, Osaka, Japan
Accepted for publication December 17, 2001.
* Address reprint requests to Dr Kobayashi, Department of Cardiovascular Surgery, National Cardiovascular Center, 5-7-1 Fujishirodai, Suita, Osaka 565-8565, Japan
e-mail: jkobayas{at}hsp.ncvc.go.jp
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Abstract
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A 39-year-old man had cor triatriatum (Lucas-Schmidt type IA) with severe mitral regurgitation and atrial fibrillation. We performed resection of the anomalous septum between the accessory chamber and the left atrium, and conducted mitral valve repair and the maze procedure. The patient regained sinus rhythm and normal pulmonary venous drainage to the left ventricle without mitral regurgitation. Histological examination demonstrated fibrotic myocardial structures in the anomalous septum. The maze procedure and complete excision of the anomalous septum proved to be effective surgical treatment for atrial fibrillation with cor triatriatum.
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Introduction
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Not only valvular and ischemic heart disease, but also congenital anomaly can be a cause of atrial fibrillation (AF). The maze procedure for AF has already been applied successfully in various congenital anomalies [1]. We herein demonstrate successful surgical treatment of a patient with cor triatriatum and mitral regurgitation associated with AF
A 39-year-old man was referred to our institution with the diagnosis of cor triatriatum and severe mitral regurgitation. He had a 5-year history of AF. Chest roentgenogram showed a cardiothoracic ratio of 57%. On the electrocardiogram, AF with an F wave of 0.15 mV in the V1 lead as found.
Echocardiography revealed the presence of the accessory atrial chamber, which was separated from the left atrium by the anomalous septum. The interatrial septum was intact. Therefore cor triatriatum was classified as Lucas-Schmidt IA. Mean pressure gradient between the accessory atrial chamber and the left atrium was calculated to be 6 mm Hg by pulsed Doppler study. Mitral regurgitation through the central area of the valve orifice was severe. Left ventricular dimension in diastole and systole were 67 mm and 51 mm respectively. The left atrium was significantly dilated to 61 mm in diameter (Fig 1).
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Fig 1. (A) Transesophageal echocardiography clearly demonstrated the accessory chamber, the anomalous membranous septum, and severe mitral regurgitation. The dimension of the left atrium was 61 mm. (B) After repair of the mitral valve, regurgitation disappeared completely.
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The operation was carried out through a standard median sternotomy. Cardiopulmonary bypass was started with ascending aortic and bicaval cannulation. After cross-clamping the aorta and administration of tepid blood cardioplegia, the accessory atrial chamber was incised in front of the right pulmonary veins. All of the pulmonary veins were connected to the accessory chamber. The accessory chamber had communication only with the left atrium through two holes on the anomalous septum. Each of the holes was about 1.0 cm in diameter. Pulmonary veins were completely isolated from the accessory chamber. The anomalous septum between the chamber and the left atrium was entirely excised, and the excessive left atrial wall was also resected to make the left atrium smaller (Fig 2).
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Fig 2. (A) Operative view after the circular incision around the pulmonary veins. The accessory chamber communicated with the left atrium by means of two holes (the forceps is passing through the holes) on the abnormal septum. (B) Excision of the whole tissue of the anomalous septum, the division of the superior vena cava, and the circular incision around the orifices of pulmonary veins provided excellent exposure of the mitral valve.
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The main cause of mitral regurgitation was a remarkable dilatation of the annulus, which was more than 40 mm in diameter. There was no obvious prolapse of the mitral leaflets. After suturing a cleft on the posterior leaflet, a Duran ring (Medtronic Inc, Minneapolis, MN) was applied on the annulus. We carried out cryoablation for the maze procedure on both atria. Postoperative echocardiography demonstrated no mitral regurgitation or no residual pressure gradient in the left atrium (Fig 1). The pathological examination revealed an anomalous septum containing myocardial structures with severe fibrotic degeneration. Sinus rhythm was restored and successfully maintained for 3 years after the operation.
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Comment
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Cor triatriatum occurs in 0.1% of children with congenital heart disease [2]. AF was sometimes associated with cor triatriatum in aged patients in previous reports [2, 3]. Regaining sinus rhythm was very important to prevent stroke after mitral valve repair without anticoagulation therapy.
In the present case, echocardiography revealed severe mitral regurgitation and a dilated left atrium. AF had been sustained for 5 years before the operation. We considered that the sinus rhythm restoration could not be obtained without the concomitant maze procedure [4].
Although the mechanism of the manifestation of AF in cor triatriatum has not been delineated, the large accessory chamber, the enlarged left atrium due to severe mitral regurgitation, and the anomalous septum are thought to have played an important role in the occurrence of AF in the present case. Interestingly, the anomalous septum contained a myocardial structure with severe fibrotic degeneration, which might contain a micro- or macro-reentry circuit. Ectopic beat from the pulmonary vein, which had a pressure overload before the operation, can contribute to the initiation of AF [5].
To abolish all of the possible causes of sustained AF, we made a circular incision around the orifices of the pulmonary veins, and resected the whole tissue of the anomalous septum and the excessive wall of the left atrium, in addition to our conventional maze procedure with cryoablation to interrupt the major macroreentry circuits.
Postoperative echocardiography showed no mitral regurgitation. Sinus rhythm was successfully restored and maintained for 3 years by the maze procedure, and mitral valve replacement was avoided. Therefore, anticoagulation therapy was unnecessary, and thromboembolism and bleeding complications were not observed. We consider that the maze procedure is effective and feasible for patients with AF associated with cor triatriatum.
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References
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- Kobayashi J., Kosakai Y., Kawashima Y. Maze procedure and anomalous coronary artery. Ann Thorac Surg 1996;61:1008-1011.[Abstract/Free Full Text]
- Nagatsu M. Clinical classification and surgical treatment of cor triatriatum. Jpn J Cardiothorac Surg 1992;40:473-484.
- Raggi P., Vasavada B.C., Parente T., Prasada S., Sacca T.J. Uncommon etiologies of atrial fibrillation. Clin Cardiol 1996;19:513-516.[Medline]
- Obadia J.F., Farra M.E., Bastien O.H., Lievre M., Martelloni Y., Chassignolle J.F. Outcome of atrial fibrillation after mitral valve repair. J Thorac Cardiovasc Surg 1997;114:179-185.[Abstract/Free Full Text]
- Chen S.A., Hsieh M.H., Tai C.T., et al. Initiation of atrial fibrillation by ectopic beats originating from the pulmonary veins: electrophysiological characteristics, pharmacological responses, and effects of radiofrequency ablation. Circulation 1999;100:1879-1886.[Abstract/Free Full Text]
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Abstract
Introduction
