failure of a valve to perform its fundamental function: insurance of one-way flow; manifested by regurgitation of blood in the opposite direction when the valve is supposed to be closed.
car·di·ac val·vu·lar in·com·pe·tence
(kahr'dē-ak val'vyū-lăr in-kom'pĕ-tĕns) Failure of a valve to close its aperture completely and prevent regurgitation of blood.