Rupture of the papillary muscle with an acute myocardial infarction is a cause of which condition?

• A. Acute MR
• B. Chronic MR
• C. Aortic regurgitation
• D. Pulmonary embolism

Answer: (A)

Rupture of a papillary muscle during an acute myocardial infarction causes sudden mitral regurgitation. The papillary muscles anchor the mitral leaflets via chordae tendineae, keeping them closed during systole. When one ruptures, the leaflets can no longer coapt properly, so blood regurgitates from the left ventricle back into the left atrium with each beat. This rapid, new-onset mitral regurgitation leads to acute volume overload of the left atrium and pulmonary circulation, causing pulmonary edema and hemodynamic collapse if not treated promptly. This scenario specifically results in acute mitral regurgitation, not chronic MR, aortic regurgitation, or pulmonary embolism.