Immediate Management of STEMI
For patients presenting with STEMI, immediately activate the catheterization laboratory and transfer for primary PCI within 120 minutes of first medical contact, while simultaneously administering aspirin 150-325 mg (chewable or IV), a P2Y12 inhibitor, anticoagulation, and supplemental oxygen only if hypoxic (SpO2 <90%). 1, 2
Initial Assessment and Stabilization (Within 10 Minutes)
- Obtain 12-lead ECG within 10 minutes of first medical contact to confirm STEMI diagnosis 2
- Initiate continuous cardiac monitoring with defibrillator capacity immediately 1
- Administer oxygen only if oxygen saturation <90%—routine supplemental oxygen in normoxic patients has not shown benefit and should be avoided 2, 1
Immediate Pharmacotherapy
Antiplatelet Therapy
- Aspirin 150-325 mg chewable (or 250-500 mg IV if oral not possible) immediately upon STEMI recognition 1, 3
- P2Y12 inhibitor before or at time of PCI:
Anticoagulation
- Unfractionated heparin (UFH) weight-adjusted IV bolus followed by infusion, or enoxaparin as alternative 1, 2
- Prehospital administration of enoxaparin is reasonable as alternative to UFH in systems currently using UFH 2
Symptom Management
- Morphine 4-8 mg IV with additional 2 mg doses at 5-15 minute intervals for pain control 5
- Nitroglycerin (sublingual or IV) for ongoing chest pain, avoiding use if hypotensive, marked bradycardia/tachycardia, or right ventricular infarction 5
Reperfusion Strategy Decision Algorithm
Primary PCI Available Within 120 Minutes
- Immediate transfer to PCI-capable facility without fibrinolysis (Class I recommendation) 2, 1
- Bypass emergency department and transfer directly to catheterization laboratory if diagnosed prehospitally 2
- Door-to-device time must not exceed 90 minutes (or 60 minutes if presenting within 120 minutes of symptom onset) 2
Primary PCI NOT Available Within 120 Minutes
- Administer fibrinolytic therapy within 30 minutes of first medical contact if no contraindications 2
- Use fibrin-specific agent (alteplase, reteplase, or tenecteplase at full dose for patients <75 years; half dose for ≥75 years) 6
- Immediately transfer to PCI-capable center for angiography within 3-24 hours after fibrinolysis 2, 1
Special Timing Considerations
- For patients presenting within 2 hours of symptom onset: immediate fibrinolysis may be considered if expected delay to PCI >60 minutes 2
- For prehospital fibrinolysis: reasonable when transport times to PCI exceed 30 minutes 2
Critical Pitfalls to Avoid
- DO NOT combine fibrinolytic therapy with immediate PCI—this combination increases harm without mortality benefit (Class III: Harm) 2, 1
- DO NOT delay reperfusion beyond 120 minutes—every minute of delay significantly increases mortality 2, 1
- DO NOT administer routine supplemental oxygen to normoxic patients—no benefit demonstrated and may be harmful 2, 1
- DO NOT use prasugrel in patients with prior stroke/TIA—contraindicated due to increased intracranial hemorrhage risk 4
- DO NOT administer prasugrel loading dose before coronary anatomy is known in UA/NSTEMI—increased bleeding risk in patients requiring urgent CABG 4
Post-Cardiac Arrest Considerations
- For patients with return of spontaneous circulation (ROSC) after cardiac arrest with STEMI: perform emergent coronary angiography immediately rather than delayed or not at all 1
Regional Network Requirements
- Ambulance teams must be trained and equipped to identify STEMI with ECG recorders and telemetry, and administer initial therapy 2
- Primary PCI-capable centers must deliver 24/7 service and be able to start primary PCI within 60 minutes from initial call 2
- All hospitals and EMS must record and monitor delay times to achieve quality targets: first medical contact to ECG ≤10 minutes, first medical contact to PCI ≤90 minutes 2