Inferior STEMI With Right Ventricular Infarction After Nitroglycerin
A 67-year-old man with hypertension and a 40-pack-year smoking history presents with 90 minutes of crushing substernal chest pain, nausea, and sweating. EMS administered aspirin 324 mg and one sublingual nitroglycerin tablet. On arrival, he is pale and diaphoretic: blood pressure 84/52 mmHg, heart rate 52/min, respiratory rate 22/min, SpO2 96% on 2 L nasal cannula. His lungs are clear, and there is no jugular venous distension. The 12-lead ECG shows 2-3 mm ST elevation in leads II, III, and aVF with reciprocal depression in I and aVL. A right-sided lead, placed because of the inferior pattern, shows 1 mm ST elevation. Bedside ultrasound shows a hyperdynamic left ventricle with underfilled chambers and no pericardial effusion. The nearest catheterization laboratory is 35 minutes away; the local ED has fibrinolysis capability but no on-site PCI. His pain persists, and he remains hypotensive after 500 mL of balanced crystalloid.
1. What is the immediate pharmacologic and fluid management, and why is nitroglycerin hazardous here?
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Immediate management. This is an inferior STEMI with right ventricular involvement and nitroglycerin-induced hypotension. Stop nitrates. Give a 250-500 mL bolus of balanced crystalloid and repeat cautiously while monitoring blood pressure and lungs; the RV is preload-dependent. Use atropine for symptomatic bradycardia if needed, but avoid relying on it for hypotension from RV infarct. Start aspirin already given, add a P2Y12 inhibitor and anticoagulation per STEMI pathway if no contraindication. Opioids should be used sparingly because they can worsen hypotension and mask response. Arrange reperfusion immediately. The reasoning is that RV output depends on filling, so venodilation and reduced preload are poorly tolerated; the clear lungs and underfilled chambers support fluid responsiveness rather than cardiogenic pulmonary edema.
2. How should you choose the reperfusion strategy given a 35-minute transfer to PCI?
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Reperfusion strategy. Primary PCI is preferred if it can be achieved within 120 minutes of first medical contact. A 35-minute transport plus catheterization team activation likely fits that window, so transfer for PCI is appropriate while stabilizing with fluids and pressors. Fibrinolysis is reserved for when PCI cannot be delivered in time and there is no contraindication; inferior MI with RV involvement can be particularly sensitive to reperfusion hypotension, so the receiving center must be ready. Do not give fibrinolysis simply because the local ED has it. The reasoning is that PCI gives more reliable reperfusion and lower intracranial hemorrhage risk; the decision is time-to-PCI, not distance alone.
3. What if he develops complete AV block and remains hypotensive?
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Complete AV block. In inferior MI, AV block is often nodal and transient. Give atropine 0.5 mg IV and repeat as needed for symptomatic bradycardia. If hypotension persists, use transcutaneous pacing, but analgesia and sedation and mechanical capture can be difficult; pacing may not restore output if the RV is underfilled. Continue fluids and consider a temporary transvenous pacing wire or chronotropic support. The definite treatment is reperfusion. The reasoning is that the block is usually ischemia-related, so pacing is a bridge and not a substitute for revascularization.