A 65-year-old man develops a pansystolic murmur at the left sternal border 5 days after an anterior STEMI. He deteriorates haemodynamically. Echocardiography is MOST likely to show which complication?
- A Acute mitral regurgitation due to papillary muscle rupture
- B Ventricular septal defect (VSD) ✓
- C Left ventricular free wall rupture
- D Pericardial effusion with tamponade
Correct answer: B. Ventricular septal defect (VSD)
Explanation
Post-infarction VSD classically presents 3-7 days after MI with a new pansystolic murmur, often loudest at the left sternal border with a thrill, accompanied by haemodynamic deterioration. It is more common after anterior or inferior MI with RCA involvement. Acute mitral regurgitation from papillary rupture also causes a pansystolic murmur but is loudest at the apex and radiates to the axilla. Free wall rupture causes tamponade without a loud murmur. Echo with colour Doppler confirms the left-to-right shunt through the VSD.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
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