Obstructive intracardiac lesions, like mitral stenosis or insufficiency (MR), by myxomas of the left atrium have been commonly reported, but the attenuation of MR by myxoma combined with coronary artery disease is very rare. We report a 70-year-old female patient whose left atrial myxoma had attenuated moderate MR to mild MR and required mitral valve surgery after removal of the myxoma. She also had coronary artery disease, severe pulmonary hypertension and moderate tricuspid regurgitation due to the mitral valve lesions obstructed by myxoma. The patient underwent removal of myxoma, mitral and tricuspid valve reconstructions, and coronary artery bypass grafting. She was discharged at the postoperative 14 day without any problems.