Subvalvular left ventricular false aneurysm complicating mitral valve replacement.

Surgical replacement of the mitral valve by a prosthetic valve may lead to localized disruption of atrioventricular continuity resulting from direct surgical trauma or from delayed rupture of the weakened annulus. Such disruption leads to subepicardial hematoma formation that may remain localized if pericardial adhesions are present. Of two patients who suffered this complication, the first died of rupture of the epicardial hematoma. The hemorrhage in the second patient was contained by pericardial adhesions and had organized, thus resulting in a subannular left ventricular false aneurysm. The aneurysm was found incidentally at autopsy after the patient died of cerebral embolism from prosthetic valve thrombi.