Inferior STEMI With Hypotension and Bradycardia
You respond to a 58-year-old man with 45 minutes of crushing substernal chest pain radiating to the jaw, nausea, and diaphoresis. He is pale and anxious. Vital signs: BP 92/58, HR 54, RR 20, SpO2 97% on room air, temperature 36.8°C. Lungs are clear bilaterally. He has no known drug allergies and no history of erectile dysfunction medication use. The 12-lead shows 3 mm ST elevation in leads II, III, and aVF, with ST depression in I and aVL; lead III elevation is greater than lead II. The nearest community ED is 12 minutes away and has no PCI capability. The PCI center is 48 minutes away by ground; helicopter is not available. Medical direction allows transport to PCI if the patient is stable enough. You are an ALS unit with aspirin, nitroglycerin, fentanyl, and 1,000 mL normal saline.
1. What is the most likely diagnosis and immediate risk, and how does the 12-lead pattern change your treatment?
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The pattern is an acute inferior STEMI, likely RCA occlusion; ST elevation in III greater than II and depression in I/aVL supports inferior injury, and hypotension plus bradycardia raises concern for right ventricular involvement. In RV infarction, the ventricle is preload-dependent, so nitroglycerin can cause profound hypotension. Do not give nitro. Give aspirin 324 mg chewed if no allergy, fentanyl for pain cautiously, and a cautious 250 mL normal saline bolus, reassessing BP. Atropine 1 mg may be used for symptomatic bradycardia, but the key is avoiding nitro and supporting preload. Obtain a right-sided lead if available; do not delay transport.
2. Destination decision: 12 minutes to a community ED without PCI versus 48 minutes to a PCI center. Defend one choice.
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I would choose the PCI center if he remains transport-stable after a cautious fluid bolus. The absolute difference is 36 minutes, but primary PCI is definitive reperfusion; a community ED without PCI can only stabilize and transfer, adding delay. His BP 92/58 and HR 54 make him borderline, so I would reassess after 250-500 mL saline, keep him supine, and monitor for deterioration. If he remains hypotensive, becomes confused, or develops airway compromise, the 12-minute community ED is safer for stabilization. Notify medical direction and the PCI center early. The decision is not 'STEMI always goes to PCI'-it is PCI if the patient can tolerate the longer transport.
3. En route he becomes more hypotensive, BP 76/44, HR 48, and confused. What do you do?
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Stop any nitroglycerin, lay him flat with legs elevated if tolerated, and give a rapid normal saline bolus (e.g., 500 mL) while reassessing. Give atropine 1 mg IV for symptomatic bradycardia, repeat up to 3 mg; if no response, initiate transcutaneous pacing and consider a push-dose vasopressor per protocol. Recheck the rhythm-he may have progressed to a higher-grade block. Notify the receiving facility and reconsider destination: with refractory shock, the closer ED may be necessary. Avoid giving more nitro and avoid excessive fluid after the BP improves, because RV infarction can be volume-sensitive.