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).
Mitral valve prolapse and regurgitation. The mitral valve separates the two chambers (atrium and ventricle) of the left side of the heart. In mitral valve prolapse, the leaflets of the mitral valve bulge (prolapse) into the left atrium like a parachute during the heart's contraction.itral valve regurgitation causes. Mitral valve regurgitation is classified as primary and secondary. Primary mitral valve regurgitation is caused by an abnormality in the mitral valve. Secondary mitral valve regurgitation is caused by an abnormality in the left ventricle of the heart.