Critical Care · Year 4 · from Critical Care
Case 3: Cardiogenic Shock - Acute MI with Pump Failure
Clinical Image
Source: Wikimedia Commons - Cardiogenic Shock - CC BY 3.0
Case Presentation
A 65-year-old man with hypertension and hyperlipidemia presents with 4 hours of crushing substernal chest pain radiating to his left arm, associated with diaphoresis and nausea. On arrival, vital signs show heart rate 105 bpm, respiratory rate 26/min, blood pressure 88/62 mmHg (MAP 71), and SpO2 92% on room air. ECG shows ST-segment elevation in leads V1-V4 consistent with anterior STEMI. Troponin I is markedly elevated at 15.2 ng/mL. Physical examination reveals cool, mottled extremities, JVP elevated at 12 cm, bibasilar crackles on lung auscultation, and a new S3 gallop. Bedside echocardiography shows severely reduced left ventricular ejection fraction (estimated 20%) with akinesis of the anterior wall and septum. Lactate is 4.8 mmol/L. He is diagnosed with cardiogenic shock secondary to acute anterior STEMI. The STEMI activation is called, and he is taken emergently for cardiac catheterization. Given his hypotension, a small fluid bolus (250 mL) is given cautiously, and dobutamine is initiated at 5 mcg/kg/min for inotropic support. As blood pressure continues to decline, norepinephrine 0.1 mcg/kg/min is added for vasoconstriction. In the cath lab, a complete occlusion of the proximal LAD is found and successfully stented. Post-PCI, an intra-aortic balloon pump (IABP) is placed for additional hemodynamic support. Over the next 72 hours, his ejection fraction improves to 35%, and inotropes and IABP are weaned. He is started on guideline-directed medical therapy for heart failure.
Key Learning Points
- Cardiogenic shock presents with signs of congestion (elevated JVP, pulmonary edema) AND hypoperfusion (cool extremities, altered mentation, oliguria, elevated lactate)
- The hemodynamic profile shows elevated CVP/PCWP, low cardiac output, and elevated SVR (heart is failing despite high filling pressures)
- Management of cardiogenic shock from acute MI prioritizes emergent revascularization (PCI within 90 minutes); delays in reperfusion worsen outcomes
- Inotropes (dobutamine) augment cardiac contractility; vasopressors (norepinephrine) may be needed for severe hypotension; mechanical support (IABP, Impella, ECMO) provides a bridge to recovery or definitive therapy