A 38-year-old woman is resuscitated after 15 minutes of witnessed ventricular fibrillation (VF) in the ICU. Return of spontaneous circulation (ROSC) is achieved after 3 defibrillation attempts and epinephrine. She remains comatose. The team wishes to assess for post-resuscitation myocardial dysfunction and guide inotropic support. Which investigation is most appropriate?

Explanation

## Post-Resuscitation Myocardial Assessment ### Rationale for Echocardiography **Key Point:** Transthoracic echocardiography is the investigation of choice to assess post-resuscitation myocardial dysfunction. It provides real-time assessment of left ventricular systolic and diastolic function, regional wall motion abnormalities, and right ventricular function — all critical for guiding hemodynamic support. **High-Yield:** Post-resuscitation myocardial dysfunction (PRMD) is common after prolonged CPR and manifests as global or regional wall motion abnormality with reduced LVEF. Echocardiography can be performed at the bedside in the ICU without patient transport, making it ideal for hemodynamically unstable patients. ### Comparison of Investigations for Myocardial Assessment | Investigation | Timing | Bedside | Real-time Function | Guides Therapy | Identifies CAD | |---|---|---|---|---|---| | Transthoracic echo | Immediate | Yes | Yes (LVEF, RV, diastolic) | Yes (inotropes, fluids) | No (unless wall motion regional) | | Coronary angiography | Delayed | No | No | No (diagnostic, not functional) | Yes | | Cardiac MRI | Delayed (hours) | No | Yes (delayed) | No (not acute) | Moderate | | Serum troponin I | Hours post-arrest | N/A | No | No (marker only) | No | **Clinical Pearl:** Post-resuscitation myocardial dysfunction typically recovers within 24–72 hours with supportive care. Echocardiography at the bedside allows immediate identification of reduced LVEF, guides escalation of inotropic support (dobutamine, milrinone), and helps differentiate cardiogenic shock from other causes of post-arrest hypotension. **Warning:** Serum troponin is elevated in >50% of cardiac arrest survivors due to myocardial ischemia but does NOT quantify function or guide acute management. Coronary angiography is indicated if there is evidence of acute coronary syndrome (ECG changes, regional wall motion abnormality on echo) but is not the first-line investigation for assessing myocardial dysfunction itself. ### Clinical Context In a comatose post-ROSC patient, rapid bedside echocardiography answers critical questions: Is the left ventricle globally depressed or regionally abnormal? Is the right ventricle dilated (suggesting pulmonary embolism or RV infarction)? What is the LVEF? These answers directly inform vasopressor/inotrope selection and fluid management.