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 may also be caused or made worse by problems with the valves on the left side of the heart (mitral or aortic valve) or the left ventricle (which pumps blood from the heart to the rest of the body). It may also be due to any cause of pulmonary hypertension (high pressure in the lung circulation).