A 64-year-old woman is 5 days after a lateral STEMI. She suddenly collapses while ambulating in the ward. On arrival she is pulseless; ECG shows organized QRS complexes without a palpable femoral pulse. Neck veins are distended. What is the most likely mechanical complication?

• A Rupture of the interventricular septum
• B Free wall rupture with hemopericardium and cardiac tamponade ✓
• C Acute mitral regurgitation from papillary muscle rupture
• D Ventricular tachycardia degenerating to pulseless electrical activity

Explanation

Free wall rupture typically occurs 3 to 7 days after MI and presents as sudden collapse with electromechanical dissociation: organized electrical activity on the monitor with no pulse, plus signs of tamponade such as distended neck veins. Septal rupture and papillary muscle rupture produce murmurs and shock rather than instant PEA. The absence of ventricular arrhythmia on the tracing argues against primary VT.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.