Acute Coronary Syndromes Algorithm

Step 1:
Symptoms suggestive of ischemia or infarction

Step 2:
EMS assessment and care and hospital preparation:
     • Monitor, support ABCs. Be prepared to provide CPR and defibrillation
     • Administer aspirin and consider oxygen, nitroglycerin, and morphine if needed
     • Obtain 12-lead ECG; if ST elevation:
     • Notify receiving hospital with transmission or interpretation; note time of onset and first medical contact
     • Notified hospital should mobilize hospital resources to respond to STEMI
     • If considering prehospital fibrinolysis, use fibrinolytic checklist

Step 3:
Concurrent ED assessment (<10 minutes)
     • Check vital signs; evaluate oxygen saturation
     • Establish IV access
     • Perform brief, targeted history, physical exam
     • Review/complete fibrinolytic checklist (Figure 2); check contraindications (Table 5)
     • Obtain initial cardiac marker levels, initial electrolyte and coagulation studies
     • Obtain portable chest x-ray (<30 minutes)

Immediate ED general treatment
     • If O2 sat <94%, start oxygen at 4 L/min, titrate
     • Aspirin 160 to 325 mg ( if not given by EMS)
     • Nitroglycerin sublingual or spray
     • Morphine IV if discomfort not relieved by nitroglycerin

Step 4:
ECG interpretation
[Proceed to Step 5, Step 9, or Step 13]

Step 5:
ST elevation or new or presumably new LBBB; strongly suspicious for injury
ST-elevation MI (STEMI)
[Proceed to Step 6]

Step 6:
     • Start adjunctive therapies as indicated (see text)
     • Do not delay reperfusion
[Proceed to Step 7]

Step 7:
Time from onset of symptoms

≤12 hours? [Proceed to Step 8]
>12 hours? [Proceed to Step 10]

Step 8:
Reperfusion goals:
Therapy defined by patient and center criteria (Table 1)
     • Door-to-balloon inflation (PCI) goal of 90 minutes
     • Door-to-needle (fibrinolysis) goal of 30 minutes

Step 9:
ST depression or dynamic T-wave inversion; strongly suspicious for ischemia
High-risk unstable angina/non-ST-elevation MI (UA/NSTEMI)
[Proceed to Step 10]

Step 10:
Troponin elevated or high-risk patient
(Tables 3, 4 for risk stratification).
Consider early invasive strategy if:
     • Refractory ischemic chest discomfort
     • Recurrent/persistent ST deviation
     • Ventricular tachycardia
     • Hemodynamic instability
     • Signs of heart failure
[Proceed to Step 11]

Step 11:
Start adjunctive treatments as indicated (see text)
     • Nitroglycerin
     • Heparin (UFH or LMWH)
     • Consider: PO β-blockers
     • Consider: Clopidogrel
     • Consider: Glycoprotein IIb/IIIa inhibitor
[Proceed to Step 12]

Step 12:
Admit to monitored bed
Assess risk status (Tables 3, 4)
Continue ASA, heparin, and other therapies as indicated
     • ACE inhibitor/ARB
     • HMG CoA reductase inhibitor (statin therapy)
     • Not at high risk: cardiology to risk stratify

Step 13:
Normal or nondiagnostic changes in ST segment or T wave
Low-/Intermediate-risk ACS

Step 14:
Consider admission to ED chest pain unit or to appropriate bed and follow:
     • Serial cardiac markers (including troponin)
     • Repeat ECG/continuous ST-segment monitoring
     • Consider noninvasive diagnostic test

Step 15:
Develops 1 or more:
     • Clinical high-risk features
     • Dynamic ECG changes consistent with ischemia
     • Troponin elevated
Yes [Proceed to Step 10]
No  [Proceed to Step 16]


Step 16:
Abnormal diagnostic noninvasive imaging or physiologic testing?
Yes [Proceed to Step 12]
No  [Proceed to Step 17]

Step 17:
If no evidence of ischemia or infarction by testing, can discharge with follow-up

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