Although mitral valve replacement (MVR) is a routine procedure, it may still result in structural defects causing significant hemodynamic compromise. One very rare complication is the development of a left ventricular-right atrial fistula. The resultant intracardiac shunt is commonly associated with concomitant heart failure, and immediate surgical closure is required. The case is described of a left ventricular-right atrial fistula following MVR.