Quadricuspid aortic valve: report of three cases.

Quadricuspid aortic valve (QAV) is a very rare congenital malformation. We have encountered three patients with QAV, of whom one patient may be the eldest reported patient with this particular anatomical abnormality. In another of our patients, there was aortic regurgitation, aortic stenosis, and healed infective endocarditis, with adhesion of the tips of the cusps. In all three patients, the cusps were all of equal size. Until now, there has been very little documented evidence about the anatomical variations in QAV or its relationship with infective endocarditis. From the available literature, we conclude that the anatomical variations in patients with QAV are similar to those in patients with quadricuspid pulmonary valve, and infective endocarditis may not be an uncommon complication.