[Huge Left Thrombosis after Mitral Valvuloplasty and Maze Procedure;Report of a Case].

Generally, anticoagulation therapy is not essential for patients who maintain sinus rhythm after mitral valvuloplasty. A 66-year-old woman who had undergone mitral valvuloplasty and maze procedure for treatment of mitral valve regurgitation and atrial fibrillation 4 years ago was diagnosed as having left atrial thrombosis despite maintenance of sinus rhythm on electrocardiography. Echocardiography showed narrow mitral valvular area(1.5 cm2), loss of A wave and a huge left atrium. Repeat surgery was performed to replace the mitral valve and to remove the thrombus. The thrombus attached to the posterior wall of the left atrium with a wide basis, and was unrelated to the ablation line of maze procedure. Careful follow-up and anticoagulation therapy should be considered for patients who have a large left atrium and/or rheumatic mitral valve after valvuloplasty even though sinus rhythm is maintained.