Cardiovascular · Year 1 · from Cardiovascular

Case 2: Right Coronary Artery Occlusion with Inferior MI

Patient Presentation

Demographics: 58-year-old male

Chief Complaint: Crushing chest pain and nausea for 1 hour

History of Present Illness: A 58-year-old male with history of hypertension and smoking presents with sudden onset crushing substernal chest pain radiating to his jaw and left arm. He also reports nausea, diaphoresis, and lightheadedness. Symptoms began 1 hour ago while watching television.

Physical Examination:

  • Vital Signs: BP 92/60 mmHg, HR 48 bpm, RR 22/min, SpO2 94% on room air
  • General: Diaphoretic, pale, anxious
  • Cardiovascular: Bradycardic, regular rhythm, S4 gallop, JVP elevated to 12 cm
  • Lungs: Clear bilaterally

Workup

  • ECG: ST-segment elevation in leads II, III, aVF (inferior leads); ST depression in I, aVL (reciprocal changes); Sinus bradycardia at 48 bpm
  • Echocardiogram: Inferior and posterior wall hypokinesis, RV dilation with reduced function
  • Labs:
  • Troponin I: 8.5 ng/mL (markedly elevated)
  • CK-MB: 85 ng/mL

Diagnosis

Acute inferior STEMI due to right coronary artery (RCA) occlusion with right ventricular involvement

Anatomical Correlation: The right coronary artery supplies the inferior wall of the left ventricle (via posterior descending artery in right-dominant circulation), the right ventricle, and importantly the SA node (in 60% of people) and AV node (in 90% of people). This explains the bradycardia and hypotension seen with RCA occlusion. The RCA originates from the right aortic sinus.

Treatment

  1. Emergent cardiac catheterization with PCI to RCA
  2. IV fluids (avoid diuretics and nitrates due to RV involvement)
  3. Atropine for symptomatic bradycardia
  4. Aspirin 325 mg, P2Y12 inhibitor, heparin
  5. Temporary pacing if needed for high-grade AV block

Clinical Image

Image Description: 12-lead ECG demonstrating ST-segment elevation in inferior leads (II, III, aVF) consistent with acute inferior myocardial infarction. Reciprocal ST depression is visible in lateral leads.

Source: Wikimedia Commons - ECG showing inferior STEMI License: CC BY-SA 3.0 URL: https://commons.wikimedia.org/wiki/File:AMI_inferior.png

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