Chest Pain at 03:00 With a Normal First Troponin
A 58-year-old man presents to a rural ED at 03:00 with 90 minutes of central chest pressure radiating to the left jaw, associated with diaphoresis and nausea. He has hypertension, smokes 20 cigarettes/day, and his father died of an MI at 55. BP 148/88, HR 96, RR 18, SpO2 96% on room air, afebrile. ECG shows 0.5 mm ST depression in V4–V6 with T-wave inversion, no ST elevation. First high-sensitivity troponin is below the limit of detection, drawn 2 hours after symptom onset. The nearest PCI centre is 2 hours by road; there is no on-site cath lab and no helicopter available until 07:00.
1. How do you risk-stratify and disposition this patient, and why is a single undetectable troponin insufficient?
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Risk stratification:
- HEART score: History (highly suspicious, 2), ECG (ST depression/T inversion, 2), Age 58 (1), Risk factors ≥3 (2), Troponin undetectable (0) = 7 → high risk (~50–65% MACE at 6 weeks).
- The undetectable troponin at 2 hours does not exclude MI. High-sensitivity assays require a 0- and 1-hour (or 0- and 3-hour) serial strategy. A single value at 2 hours cannot rule out a rise, and NSTEMI can present with an initially normal troponin.
Disposition reasoning:
- This is a high-risk NSTE-ACS picture. Admit to a monitored bed, start aspirin 162–325 mg chewed, P2Y12 inhibitor per local protocol, anticoagulation per protocol, high-intensity statin, beta-blocker if no contraindication, and nitroglycerin for ongoing pain.
- Repeat troponin at 1 hour (or 3 hours if using a 0/3 protocol) and again at 6 hours.
- Transfer decision: with a 2-hour road transfer and no cath lab until 07:00, the question is timing, not whether. High-risk NSTE-ACS benefits from an early invasive strategy within 24 hours. Arrange transfer for the morning, but if he develops refractory pain, dynamic ECG changes, heart failure, or hemodynamic instability, transfer immediately by road.
Do not discharge on a single negative troponin with a HEART score of 7.
2. At 05:30 he develops 2 mm ST elevation in II, III, and aVF with worsening pain. What is your plan?
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This is now an inferior STEMI. Reassess and act.
Immediate steps:
- Confirm the ECG (repeat, check lead placement), and look for reciprocal changes in I and aVL.
- Check for right ventricular involvement: obtain V4R. If RV infarct is present, nitroglycerin and other preload-reducing agents can cause profound hypotension - avoid them.
- Aspirin already given; add a P2Y12 inhibitor and anticoagulation per STEMI protocol.
- Assess for contraindications to fibrinolysis: recent surgery, stroke, bleeding, BP >180/110, etc.
Reperfusion decision - the core judgement:
- PCI is preferred if it can be achieved within 120 minutes of first medical contact. Here, road transfer is 2 hours and it is now 05:30, so PCI is not achievable within 120 minutes.
- Therefore fibrinolysis is indicated if there are no contraindications, given symptom onset was ~03:00–05:30 (well within 12 hours). Door-to-needle should be as fast as possible.
- After lysis, transfer to the PCI centre for rescue or routine early angiography regardless of reperfusion status.
If fibrinolysis is contraindicated: transfer immediately for rescue PCI, accepting the 2-hour delay.
Monitor for reperfusion arrhythmias, bleeding, and failed reperfusion (persistent pain, persistent ST elevation at 60–90 min) → rescue PCI.