Operational elements that standardize care and reduce missed ACS.
Time Targets
ECG completed and interpreted: ≤10 minutes
Repeat ECG: for persistent/recurring pain or dynamic changes
hs‑cTn repeat draw: 1 hour (preferred) or 2 hours per assay validation
hs‑cTn Algorithms
0/1‑h: baseline and 1‑h hs‑cTn; use assay‑specific rule‑out/rule‑in cutoffs and absolute delta
0/2‑h: alternative when 1‑h logistics limited
Single‑sample rule‑out possible if symptom onset >3 h and very low hs‑cTn, nonischemic ECG, low clinical risk [2], [3]
Risk Scores (with hs‑cTn)
HEART score: history, ECG, age, risk factors, troponin
EDACS: symptom characteristics + risk factors + age
Use scores to guide disposition; target <1% 30‑day MACE for discharge cohorts [4], [2]
Red Flags for Immediate Action
ST‑elevation or new LBBB with ischemic symptoms
Hypotension, shock, new/worsening heart failure
Refractory chest pain or dynamic ST‑T changes
Concern for aortic dissection, PE, tamponade, tension pneumothorax
ACS Initial Therapies
Aspirin loading if no contraindication
Nitrates for pain/ischemia; avoid if hypotension, RV infarct, or PDE‑5 inhibitors
Anticoagulation for NSTEMI/UA when diagnosis likely
High‑intensity statin initiation for confirmed ACS
Beta‑blocker if no contraindications; defer in shock/acute HF
Disposition Guide
Low risk + negative hs‑cTn algorithm + nonischemic ECG: discharge with expedited follow‑up
Intermediate risk: observation, serial hs‑cTn/ECG ± functional or anatomic testing
High risk or positive algorithm: admit; STEMI/NSTEMI pathways