Quadricuspid aortic valve.

A quadricuspid aortic valve was observed in a patient requiring aortic valve replacement because of severe aortic regurgitation, while in another it was accidentally detected by means of transesophageal echocardiography performed during coronary artery bypass grafting. This report discusses the apparent rarity of this malformation and stresses the need for periodical controls in patients known to have a quadricuspid aortic valve.