Erythema multiforme (EM) is a skin reaction that comes from an infection or another trigger. EM is a type of allergic reaction. In most cases, it occurs in response to an infection. In rare cases, it is caused by certain medicines or body-wide (systemic) illness. Infections that may lead to EM include:
1 Heart attack. A heart attack can damage the area of the heart muscle that supports the mitral valve, affecting the function of the valve. If the damage is extensive enough, a heart attack can cause sudden and severe mitral valve regurgitation.  Abnormality of the heart muscle (cardiomyopathy).
Watch an animation of mitral valve regurgitation. A leaking mitral valve allows blood to flow in two directions during the contraction. Some blood flows from the ventricle through the aortic valve â as it should â and some blood flows back into the atrium.f regurgitation is severe enough, the forward flow of blood is reduced enough to cause heart failure (when the heart does not pump enough blood to the body) which may produce also symptoms ranging from shortness of breath during exertion, coughing, congestion around the heart and lungs, swelling of the legs and feet.