If severe left ventricular systolic dysfunction is present, then the mitral valve should not be surgically repaired. In this situation, repairing/replacing the mitral valve will significantly increase the afterload, which the dysfunctional left ventricle will not be able to tolerate. When severe mitral regurgitation is present, the blood can be ejected in two directions from the left ventricle (the normal route through the aortic valve or abnormally backward through the regurgitant mitral valve). Closing one of these routes will put an extra workload on the left ventricle. If the left ventricle is not able to handle this, cardiogenic shock and death will ensue. Specifically, the American Heart Association guidelines recommend medical therapy alone for patients with left ventricular ejection fraction < 30% and/or end systolic dimension > 55 mm when mitral valve repair is not likely.