Emergency Medicine · Cardiology
Acute Coronary Syndrome
STEMI vs NSTEMI/UA Pathway · Antiplatelets · Anticoagulants · Time Targets
STEMI
ECG: ST elevation ≥1mm (≥2 leads) or LBBB (new)
Troponin markedly elevated
Complete occlusion of coronary artery
Immediate reperfusion therapy
Primary PCI: preferred if <120min door-to-balloon
Fibrinolysis if PCI not available <120min
🎯 Door-to-Balloon: <90 min
NSTEMI
ECG: ST depression / T-wave changes / normal
Troponin elevated (positive)
Partial coronary occlusion
Risk-stratify: TIMI / GRACE score
High risk → early invasive (<24h)
Very high risk → urgent (<2h): refractory ischemia, hemodynamic instability
🎯 Cath: <24h (high risk) / <72h (intermediate)
Unstable Angina
ECG: Dynamic changes / normal
Troponin negative
New-onset severe angina, rest angina, crescendo angina
Risk-stratify with serial ECG + troponins × 3
Rule out NSTEMI (high-sensitivity troponin at 0h/1h/3h)
🎯 Risk stratify → selective invasive strategy
🏥 Initial Management — All ACS (First 10 Minutes)
M
Morphine 2–4 mg IV PRN (use cautiously — may ↑ mortality in NSTEMI)
O
O₂ if SpO₂ <90%; avoid routine O₂ if SpO₂ ≥90%
N
Nitrates SL NTG 0.4 mg q5min × 3; IV if BP ≥90; avoid if PDE-5 inhibitor ≤24–48h
A
Aspirin 325 mg PO chewed immediately (unless allergy). Continue 81 mg/day
💊 Antiplatelet Therapy (DAPT)
Aspirin STEMI + NSTEMI
Loading: 325 mg PO | Maintenance: 81 mg/day
First agent in all ACS. Lifelong dual antiplatelet.
Ticagrelor Preferred P2Y12
Loading: 180 mg PO | Maintenance: 90 mg BID
Preferred over clopidogrel (PLATO trial). Dyspnea side effect. Avoid with prior intracranial hemorrhage.
Prasugrel STEMI/PCI
Loading: 60 mg PO | Maintenance: 10 mg/day
Avoid if prior TIA/stroke, age ≥75, <60 kg (5 mg/day), pending CABG. TRITON-TIMI 38.
Clopidogrel Alternative
Loading: 300–600 mg PO | Maintenance: 75 mg/day
Use when ticagrelor/prasugrel contraindicated. Variable response (CYP2C19 polymorphism).
💉 Anticoagulation (ACT)
UFH (Heparin) STEMI + NSTEMI
60 U/kg IV bolus (max 4000U) → 12 U/kg/h (max 1000 U/h)
Target aPTT 50–70 sec. Preferred for STEMI → PCI. ACT 250–300 sec during PCI.
Enoxaparin NSTEMI preferred
1 mg/kg SC q12h (if CrCl ≥30) | or 30 mg IV bolus first
Preferred over UFH for NSTEMI (SYNERGY trial). Reduce to 1 mg/kg q24h if CrCl <30.
Bivalirudin PCI
0.75 mg/kg IV bolus → 1.75 mg/kg/h
Direct thrombin inhibitor. Preferred in HIT. Less bleeding than UFH + GPI.
Fondaparinux Conservative NSTEMI
2.5 mg SC daily
Lowest bleeding risk. Avoid as sole agent during PCI (catheter thrombosis risk — add UFH).
⏱️ Critical Time Targets (ACC/AHA Guidelines)
STEMI Door-to-Balloon (PCI)
<90 min
From first medical contact
STEMI Door-to-Needle (Lytic)
<30 min
If PCI unavailable in 120 min
NSTEMI High-Risk PCI
<24 h
GRACE >140 or troponin rise
NSTEMI Very High Risk
<2 h
Hemodynamic instability, cardiogenic shock, VF
12-Lead ECG
<10 min
From arrival / first contact
Aspirin + P2Y12
ASAP
Before PCI in all ACS
Transfer to PCI Centre
<120 min
From STEMI diagnosis
Troponin (hs-cTn)
0h/1h
Serial sampling protocol (ESC)
CCM Notes · FOAMed · Critical Care Clinical Reference
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Based on ACC/AHA & ESC ACS Guidelines
Educational use only