[Quadricuspid Aortic Valve Diagnosed During Surgery in an Elderly Patient with Aortic Stenosis and Regurgitation:Report of a Case].

We report case details of a quadricuspid aortic valve that was diagnosed during surgery in an 82-yearold male with aortic valve stenosis and regurgitation. He had been treated for heart failure with atrial fibrillation, and aortic valve dysfunction. Sinus rhythm was restored after second catheter ablation for atrial fibrillation. However, heart failure symptoms associated with aortic valve stenosis and regurgita-tion remained, and surgical treatment was planned. Intraoperative findings revealed a quadricuspid aortic valve that was not diagnosed during preoperative examination. It can be difficult to detect a quadricuspid aortic valve on preoperative cardiac echocardiography if valve leaflets are calcified and poorly mobile. It is important to match the commissure at one location with that of the prosthetic valve and sew the prosthetic valve in a manner that does not occlude the orifice of the coronary artery.