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).
In mitral regurgitation the valve does not close properly. This causes blood to leak back (regurgitate) into the left atrium when the left ventricle contracts. Basically, the more open the valve remains, the more blood regurgitates, the more severe the problem.n mitral regurgitation the valve does not close properly. This causes blood to leak back (regurgitate) into the left atrium when the left ventricle contracts. Basically, the more open the valve remains, the more blood regurgitates, the more severe the problem.