Giant Left Atrial Myxoma and Associated Mitral Valve Pathology

Abstract

EFT ATRIAL MYXOMA is infrequently associated with mitral valve pathology. A case of left atrial myxoma resection requiring mitral valve repair is described, showing the importance of intraoperative transesophageal echocardiogram (TEE) in the management of these patients. CASE REPORT A 61-year-old man presented to his family physician with a 2-month history of shortness of breath. On examination, the patient was found to be in atrial fibrillation and have a holosystolic murmur audible on the precordium. The patient denied any fevers, chest pains, syncopal episodes, or symptoms suggesting embolic phenomena. Past medical history was significant for a 150 pack/year history of smoking. The patient was started on warfarin for his atrial fibrillation and referred to the cardiology department. A transthoracic echocardiogram showed a large mass within the left atrium measuring 5.5 cm 3.2 cm. The mass was attached to the inferior part of the interatrial septum and was prolapsing across the mitral valve. The left ventricle was described as mildly dilated with preserved systolic function. Posterolaterally directed mitral regurgitation was present and was believed to be secondary to the prolapsing mass interfering with leaflet coaptation because prolapse through the valve was observed to occur during systole (Fig 1). By pulmonary vein Doppler profile, the regurgitation was severe. The left-heart catheterization showed normal coronary vessels, with the left ventricle not being entered for fear of tumor embolization. Given the size of the mass and the possibility of serious sequelae, such as obstruction or embolism, the patient consented to and underwent urgent cardiac surgery to resect the mass. An intraoperative TEE confirmed the presence of a large mass within the left atrium. The mass was attached to the interatrial septum slightly inferior to the fossa ovalis and approximately 1 cm from the mitral annulus. The echocardiographic appearance of the large mass was typical for atrial myxoma (Fig 1). The mitral valve leaflets appeared at most mildly thickened. Severe mitral regurgitation was present with an eccentric, posterolaterally directed jet. Again, it was believed that the regurgitation was caused by prolapse of the myxoma across the mitral valve and would resolve with resection of the tumor. The mediastinum was approached through a standard median sternotomy. Both the left and right atrial chambers were enlarged. Bicaval cannulation was used with both cavae encircled and snared. The patient underwent cardiopulmonary bypass (CPB). Cold antegrade cardioplegia was used to arrest the heart. A large, smooth tumor mass with a very broad base was found to occupy much of the left atrial chamber (Fig 2). The base started medial to the fossa ovalis and extended almost to the anterior annulus of the mitral valve. The tumor could not be removed through the left atrium; therefore, an oblique incision was made in the right atrium. The fossa ovalis was identified and opened; the tumor base was medial to this. Via sharp dissection, the tumor was excised by circumferentially dividing the intra-atrial septum around the tumor base. This resulted in a large defect in the septum measuring 4 cm in length and 2 cm in diameter. The medial extent of this was skirting the anterior annulus of the