Six days after her first anterior STEMI, a 70-year-old woman suddenly becomes unresponsive. There are organised narrow QRS complexes on the monitor but no palpable pulse, jugular venous distension is marked, and bedside ultrasound shows a large pericardial effusion with right atrial collapse. What is the most likely diagnosis?

• A Ventricular septal rupture
• B Acute mitral regurgitation from papillary muscle rupture
• C Sustained monomorphic ventricular tachycardia
• D Ventricular free wall rupture with haemopericardium ✓

Explanation

Free wall rupture occurs 5 to 14 days after transmural infarction, classically in elderly hypertensive women with a first MI, and produces electromechanical dissociation: organised ECG activity without a pulse. Haemopericardium causes tamponade, seen here as right atrial collapse. Septal rupture gives a murmur with biventricular failure rather than pulseless arrest, papillary muscle rupture gives severe pulmonary oedema, and sustained VT shows a wide irregular rhythm without pericardial effusion.

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

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Written and medically reviewed by the StethoPrep medical team.