Tricuspid regurgitation following inferior myocardial infarction.

Tricuspid regurgitation developed in two patients after inferior wall myocardial infarction. Neither patient had preexisting valvular heart disease or evidence of endocarditis, and neither had suffered chest trauma. Because abnormalities in right ventricular function may occur after inferior infarction, and because other known causes of tricuspid incompetence were not present, we postulate that these patients developed valvular regurgitation from dysfunction of the papillary muscle complex controlling tricuspid valve function, a mechanism similar to that proposed to explain mitral regurgitation seen with inferior wall ischemia.