Symptoms concerning for ACS⁵

STEMI or new LBBB

CP/anginal equivalent⁴ with h/o CAD, CRI, PVD, age 70, or high clinical suspicion
ST s 0.5 mm; resolve when asymptomatic
ST depression 1 mm in 2 leads
T wave inversion 2 mm in 2 leads
Positive cardiac markers

End

Cardiac markers/ECG at 0/90/180 min²
Repeat ECG with recurrent/persistent symptoms

Medical management
Admit to Cardiology

Clearly noncoronary

Cardiac markers/ECG at 0/90/180 min²
Repeat ECG with recurrent/persistent symptoms

Age >55 M; >65 F, typical angina¹ or intermediate suspicion
No new significant ECG changes⁶
Normal cardiac markers

Admit to heart ED

Arrange stress test
Collaborate with Cardiology
See stress test algorithm

Medical management
Admit to Cardiology

Atypical chest pain, low clinical suspicion
No new significant ECG changes⁶
Normal cardiac markers

Admit to heart ED
OR
Discharge with PCP follow-up for outpatient stress test

Rest myocardial perfusion imaging with Tc 99m⁷

Active CP or CP in past 2 hours

Yes

No

Results normal?

Yes

No

PCP follow-up with outpatient stress test

Medical management
Admit to Cardiology

PCP follow-up

A - High risk for STEMI
B - High risk for UA/NSTEMI
C - Intermediate risk
D - Low risk
E - Very low risk

DEFINITIONS:

¹ Typical angina:

Substernal chest pain or discomfort that is
provoked by exertion or emotional stress and
relieved by rest and/or nitroglycerin

² Cardiac marker timing: Based on symptom onset; in cases of uncertainty assume symptom onset at ED arrival

³ ECG normal: No significant ST depression/T wave inversions, BBB, LVH with repolarization, conduction defect, digoxin effect

⁴ Anginal equivalent:

Any symptoms that the physician feels may represent ACS
Exertional dyspnea—most common anginal equivalent symptom

⁵ ACS:

STE-ACS—1 mm ST elevation in 2 leads
NSTE-ACS

NSTEMI—positive cardiac biomarkers
Unstable angina—ischemia with negative biomarkers

NSTEMI—positive cardiac biomarkers
Unstable angina—ischemia with negative biomarkers

⁶ New significant ECG changes:

ST s 0.5 mm; resolve when asymptomatic
ST depression 1 mm in 2 leads
T wave inversion 2 mm in 2 leads

⁷ Regadenoson is preferred agent for chemical nuclear stress test. Technetium Tc-99m tetrofosmin is the preferred tracer.

PCI

History^*
Physical examination
12-lead ECG

A

B

C

D

E

Cardiac markers/ECG at 0 min/4 hr/8 hr²
Repeat ECG with recurrent/persistent symptoms

Abnormal

Normal

CAD, Coronary artery disease; CP, chest pain; CRI, chronic renal insufficiency; ECG, electrocardiogram; ED, emergency department; h/o, history of; LBBB, left bundle branch block; NSTE, non-ST-segment elevation; NSTEMI, non-ST-segment elevation myocardial infarction; PCP, primary care physician; PVD, peripheral vascular disease; STE, ST-segment elevation; STEMI, ST-segment elevation myocardial infarction; UA, unstable angina.