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).
Tricuspid regurgitation is a disorder in which this valve does not close tight enough. This problem causes blood to flow backward into the right upper heart chamber (atrium) when the right lower heart chamber (ventricle) contracts. An increase in size of the right ventricle is the most common cause of this condition.