A 62 year old female 1-week post stent placement for RCA infarction presents with acute chest pain and pink frothy sputum; this patient exhibits symptoms of:

• A. Ventricular septal rupture
• B. Ruptured papillary muscle
• C. Pericardial tamponade
• D. Free-wall rupture

Answer: (B)

Acute mitral regurgitation from papillary muscle rupture is the mechanism behind this presentation. After a myocardial infarction, mechanical complications can occur in the days to a week following the event. The posteromedial papillary muscle is particularly vulnerable in inferior MIs supplied by the RCA; if it ruptures, the mitral valve cusps lose their support, causing blood to jet backward from the left ventricle into the left atrium during systole. This sudden backflow elevates left atrial and pulmonary pressures, leading to rapid pulmonary edema, which manifests as pink, frothy sputum. The timing fits—typically 2 to 7 days post-MI—and the RCA involvement aligns with inferior infarcts.

In contrast, a ventricular septal rupture would produce a new harsh holosystolic murmur and signs of a left-to-right shunt due to blood crossing into the right heart. Pericardial tamponade presents with hypotension, jugular venous distention, and muffled heart sounds from blood in the pericardial space, not primarily pulmonary edema. Free-wall rupture causes sudden chest pain and rapid hemodynamic collapse from catastrophic bleeding into the pericardium. So, the pink frothy sputum and the postinfarct timing point most strongly to acute mitral regurgitation from papillary muscle rupture.