Left ventricular--right atrial shunt: an unusual cause of hemodynamic deterioration following aortic valve surgery.

Two cases of left ventricular-right atrial shunts inadvertently produced during aortic valve replacement are described. It is surprising that this complication is not more prevalent considering the close proximity of the aortic and mitral valves to the atrioventricular portion of the membranous septum. A left-to-right shunt should be a consideration in patients who fail to improve following aortic valve surgery, especially if the valve and subaortic region were heavily calcified or septal trauma occurred during the surgical procedure.