Chest Pain in a Patient You Cannot Fully Assess
A 58-year-old man with a history of hypertension and smoking presents with 45 minutes of substernal pressure radiating to the left arm, associated with nausea and diaphoresis. Vitals: HR 96, BP 148/92, RR 18, SpO2 97%. He is diaphoretic and pale. The ECG shows 2 mm ST elevation in leads II, III, and aVF, with reciprocal depression in I and aVL. The nearest PCI-capable center is 90 minutes away by ground and 25 minutes by helicopter, but weather is marginal and the helicopter is on another scene. Fibrinolytic checklist: no contraindications. Your ED has no cath lab.
1. What is the reperfusion strategy, and how do you justify it with the numbers?
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This is an inferior STEMI with a door-to-device time that will exceed the 120-minute threshold (90 min ground + door-to-balloon time >120 min; helicopter is unreliable due to weather). Per guidelines, when PCI cannot be achieved within 120 minutes of first medical contact, fibrinolysis is indicated if there are no contraindications-which the checklist confirms. Give fibrinolytic therapy now (e.g., tenecteplase weight-based single bolus) plus aspirin 162–325 mg chewed, P2Y12 inhibitor per protocol, and anticoagulation (heparin or enoxaparin per fibrinolytic regimen). Do not delay for the helicopter. Simultaneously arrange transfer to the PCI center for routine early angiography (within 2–24 hours) after successful fibrinolysis. Reassess for reperfusion (pain resolution, ST resolution, reperfusion arrhythmias) at 60–90 minutes; if failed, rescue PCI.
2. Ten minutes after fibrinolysis the patient becomes bradycardic to 42 with BP 88/50 and feels lightheaded. How do you manage this, and what does it tell you?
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This is likely a reperfusion-associated bradyarrhythmia or inferior MI with increased vagal tone / AV nodal ischemia, both common in inferior STEMI (RCA supply to the SA/AV node). Management: atropine 0.5 mg IV every 3–5 minutes (max 3 mg); if inadequate, transcutaneous pacing and/or push-dose epinephrine or a dopamine infusion. Place pacing pads prophylactically. Avoid nitroglycerin (hypotension and preload dependence in inferior MI with possible RV involvement). Obtain a right-sided ECG to assess for RV infarction-if present, give a fluid bolus and avoid nitrates, and consider inotropic support. The bradycardia does not necessarily mean failed reperfusion; monitor for progression to complete heart block, which may need transvenous pacing. Continue aspirin/P2Y12/anticoagulant and expedite transfer.