← Cardiology / EM Vault • AHA/ACC 2023 Guidelines

Acute Chest Pain & ACS Reperfusion Protocol

STEMI vs. NSTEMI vs. Unstable Angina Triage and Critical PCI Time Windows.

Door-to-Balloon ≤ 90 min Door-to-Needle ≤ 30 min
Step 1: 10-Min ECG Transmural Infarct

ST-Elevation MI (STEMI)

Criteria: ST elevation ≥ 1 mm in ≥ 2 contiguous leads (or ≥ 2 mm in V2–V3), new LBBB with Sgarbossa, or posterior MI (ST depression V1–V3 with tall R waves).

Biomarker: Troponin I/T elevated (do NOT delay cath lab waiting for lab values!).

Immediate Reperfusion Mandated
Step 2: Biomarker Triage Subendocardial

NSTEMI vs. Unstable Angina

ECG: ST depression, T-wave inversions, or normal ECG.

NSTEMI: Elevated high-sensitivity Cardiac Troponin with myocardial necrosis → Urgent coronary angiography (≤ 24h).

Unstable Angina: Normal cardiac enzymes; rest angina > 20 min or crescendo pattern.

Reperfusion Time Windows (Class I Recommendation) Time = Myocardium
PCI-Capable Center ≤ 90 min Door-to-Balloon Time
Transfer to PCI ≤ 120 min First Medical Contact to Device
Fibrinolysis (tPA) ≤ 30 min If transfer delay > 120 minutes
Immediate Medical Therapy & Contraindications MONA-BASH Protocol

• Aspirin: 324 mg chewable immediately (irreversible COX-1 inhibitor).

• P2Y12 Inhibitor: Ticagrelor 180 mg or Prasugrel 60 mg loading dose.

• Anticoagulation: Unfractionated Heparin (bolus + infusion, aPTT 50–70s).

• High-Intensity Statin: Atorvastatin 80 mg prior to PCI.

⚠ Nitroglycerin CONTRAINDICATION: Avoid in Right Ventricular Infarct (leads II, III, aVF; check V4R) or PDE-5 inhibitor use < 24–48h.

⚠ Beta-Blocker Warning: Avoid if acute heart failure, bradycardia, or PR > 0.24s.