A 60-year-old man presents with STEMI of the inferior wall 90 minutes after symptom onset. Primary PCI is performed successfully. On day 3 he develops sudden hypotension, new pansystolic murmur loudest at the lower left sternal border, and a left-to-right shunt on echocardiography. The MOST likely diagnosis is:

• A Acute mitral regurgitation due to papillary muscle rupture
• B Left ventricular free wall rupture
• C Pericardial tamponade
• D Ventricular septal rupture (post-infarction VSD) ✓

Explanation

Post-infarction ventricular septal rupture (VSD) typically presents 3–5 days after STEMI with sudden haemodynamic deterioration and a harsh pansystolic murmur at the left sternal border; an oxygen step-up (left-to-right shunt) from right ventricle compared to right atrium confirms the diagnosis on right heart catheterization or echocardiography. Papillary muscle rupture also causes a pansystolic murmur but produces severe mitral regurgitation without a shunt. Free wall rupture causes tamponade with sudden death or pulseless electrical activity, not a murmur.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.