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2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR Chest Pain Guideline

Clinical Quick Reference — Evaluation and Diagnosis of Chest Pain

Published: Journal of the American College of Cardiology (November 2021)
Societies: AHA, ACC, ASE, CHEST, SAEM, SCCT, SCMR
DOI: 10.1016/j.jacc.2021.07.053
View Full Guideline PDF

What's New in 2021

Initial Assessment of Acute Chest Pain

History and Physical Examination

Key Historical Features

  • Chest pain character (sharp, pressure, tearing, pleuritic), location, radiation
  • Associated symptoms: dyspnea, diaphoresis, nausea, syncope, palpitations
  • Risk factors: age, sex, diabetes, hypertension, smoking, dyslipidemia, family history
  • Prior cardiac history: MI, revascularization, HF, arrhythmia
  • Recent illness, immobilization, or surgery

12-Lead ECG

IObtain within 10 minutes of presentation.

  • ST Elevation (≥1 mm contiguous): STEMI—emergent reperfusion
  • ST Depression or T-Wave Changes: High-risk NSTE-ACS
  • Nonspecific Changes: Do not exclude ACS; serial ECG and troponin essential
  • Normal ECG: Does not exclude MI (5-10% of ACS have initially normal ECG)

High-Sensitivity Cardiac Troponin

IHigh-sensitivity troponins are preferred standard for biomarker diagnosis of acute myocardial infarction.

  • Draw at presentation (may be negative in first 2–3 hours)
  • Serial troponins per protocol (0/1h or 0/3h algorithms)
  • Any elevation above 99th percentile URL suggests myocardial injury
  • Distinguish AMI from troponin elevation due to HF, sepsis, PE, renal disease, arrhythmia

Do

  • Obtain ECG within 10 minutes
  • Draw troponin at presentation and per protocol
  • Assess for high-risk features (hemodynamic instability, ischemic ECG changes)
  • Perform serial ECGs if high clinical suspicion
  • Maintain high suspicion in women, elderly, and diabetics (atypical presentations)

Don't

  • Delay ECG based on perceived low-risk presentation
  • Rely on single negative troponin in early presentation
  • Assume normal ECG excludes ACS
  • Overlook atypical presentations (dyspnea, nausea without chest pain)

Risk Stratification of Acute Chest Pain

HEART Score

ICalculate HEART score in all acute chest pain patients for risk assessment and disposition.

Component012
HistoryTypical non-ACSAtypicalTypical ACS
ECGNormalNonspecific ST/TSignificant ST/T or LBBB
Age<4545–64≥65
Risk FactorsNone1–2 present≥3 present
TroponinNormal0.01–0.03>0.03

Risk Stratification

  • 0–3 (Low): ~1% MACE; consider discharge with outpatient testing
  • 4–6 (Intermediate): ~10% MACE; observation, serial biomarkers, testing
  • ≥7 (High): ~35% MACE; admission, serial troponins, cardiology consult

High-Sensitivity Troponin Protocols

0/1-Hour Algorithm (Preferred)

Draw hs-cTn at 0 and 60 minutes
Both < Lower Limit of Detection → ACS ruled out
Either ≥99th percentile URL → ACS ruled in, admit
0-to-1h rise >45% but < URL → Intermediate, may need 3-hour troponin

0/3-Hour Algorithm (Alternative)

Draw hs-cTn at 0 and 180 minutes
Both < URL → ACS ruled out
Either ≥ 99th percentile → ACS ruled in

Other Risk Tools

ToolComponentsUse
TIMI UA/NSTEMIAge, angina, risk factors, ECG, biomarkers14-day death/MI/revascularization risk
GRACEAge, Killip, BP, HR, Cr, troponin, ST changesIn-hospital and 6-month mortality

Acute Coronary Syndrome — ACS Pathway Management

STEMI Recognition and Reperfusion

IPatients with STEMI require emergent reperfusion via primary PCI or fibrinolysis.

Immediate Actions (<10 min)

  • Call 9-1-1; activate EMS for transport
  • 12-lead ECG within 10 minutes
  • IV access, labs (troponin, CBC, CMP, coagulation)
  • Aspirin 325 mg (chewed) + P2Y12 inhibitor (ticagrelor 180 mg preferred)
  • Anticoagulation (unfractionated heparin or enoxaparin)
  • Morphine for pain (2–4 mg IV, repeat as needed)
  • Activate cardiac catheterization lab

Reperfusion Strategy

  • Primary PCI (Preferred): Door-to-balloon <120 min from first ECG
  • Fibrinolysis: If PCI not available and transfer >120 min; door-to-drug <30 min

NSTE-ACS (Unstable Angina / NSTEMI)

IDual antiplatelet therapy, anticoagulation, and risk-based invasive strategy.

Medical Therapy

  • Antiplatelet: Aspirin 325 mg + P2Y12 inhibitor (ticagrelor, prasugrel, or clopidogrel)
  • Anticoagulant: Unfractionated heparin, enoxaparin, or fondaparinux
  • Beta-Blocker: Target HR 50–60 bpm if no contraindication
  • ACE-I/ARB: For LV dysfunction or diabetes
  • High-Intensity Statin: Atorvastatin 80 mg or rosuvastatin 40 mg daily

Invasive Angiography Timing

  • Very High Risk: Emergent (<2 hours) — ST depression, positive troponin, hemodynamic instability
  • High Risk: Early (<24 hours) — Dynamic ECG changes, elevated troponin
  • Intermediate Risk: Risk-stratified approach — consider stress testing or angiography as indicated

Non-ACS Causes of Acute Chest Pain

Pulmonary Embolism (PE)

Presentation

  • Sudden pleuritic chest pain, dyspnea, tachycardia
  • Risk: immobilization, surgery, malignancy, thrombophilia

Diagnosis

  • D-dimer: High NPV in low-risk patients; rules out PE if negative
  • CT Pulmonary Angiography (CTPA): Gold standard if clinical suspicion
  • ECG/CXR: Usually nonspecific

Aortic Dissection (Type A)

Presentation

  • Sudden severe "tearing" chest/back pain; hypertension, tachycardia
  • Risk: hypertension, Marfan syndrome, aortic aneurysm history
  • Signs: pulse/BP differential between arms, aortic regurgitation murmur

Diagnosis

  • CXR: Mediastinal widening, aortic knob enlargement
  • TEE or CTA: Definitive imaging
Type A dissection can elevate troponin if dissection involves coronary ostium; back pain + pulse differential should raise suspicion.

Acute Pericarditis

Presentation

  • Pleuritic, positional chest pain (worse flat, better upright); pericardial friction rub
  • Viral prodrome common

Diagnosis

  • ECG: Diffuse ST elevation (PR depression in early phases)
  • Echocardiography: Pericardial effusion
  • Troponin: May be mildly elevated (myopericarditis)

Spontaneous Pneumothorax

Presentation

  • Sudden unilateral pleuritic pain; dyspnea
  • Signs: decreased breath sounds, hyperresonance on affected side

Diagnosis

  • CXR: Visualizes pneumothorax; measure lung-chest wall distance

Do

  • Maintain high suspicion for life-threatening mimics
  • Obtain chest imaging (CXR, CTA) if non-ACS diagnosis suspected
  • Consider D-dimer or CTPA for PE risk
  • Look for back pain, pulse differential (dissection)

Don't

  • Assume normal troponin excludes life-threatening non-ACS diagnosis
  • Miss dissection because ECG or troponin appears normal
  • Discharge without objective imaging if concerned for PE or pneumothorax

Stable Chest Pain Evaluation

Pretest Probability Assessment

IEstimate pretest probability of CAD using clinical features to guide testing strategy.

Chest Pain Categorization

  • Typical Angina: Substernal discomfort with exertion, relieved by rest/nitrates, ± radiation to arm/jaw
  • Atypical Angina: Meets 2 of 3 features above
  • Nonanginal: Meets ≤1 feature; pleuritic, positional, sharp, localized

Diamond-Forrester Pretest Probability

  • Age 45–54 males: Typical 87% | Atypical 62% | Nonanginal 34%
  • Age 45–54 females: Typical 55% | Atypical 22% | Nonanginal 7%
  • Age >65: All presentations carry higher pretest probability

Management by Risk

Low Pretest Probability (<5%)

Reassurance; minimal testing unless high-risk features

Intermediate (5–72%)

Functional testing (stress ECG/echo/nuclear) OR anatomic (CCTA)

High (>72%)

Consider direct angiography if high-risk features; stress testing if low-risk features

Noninvasive Testing Selection

Testing Modalities Comparison

TestSensitivitySpecificityAdvantagesDisadvantages
Stress ECG 68% 77% Inexpensive, functional capacity Limited in LBBB/LVH, baseline ST abnormality
Stress Echo 80% 86% Wall motion detail, valve assessment Operator dependent, cost
Nuclear (MPI) 85% 70% High sensitivity, extensive evidence Radiation, false positives in women/LBBB
CCTA 95% 85% High sensitivity, anatomy, rule-out Radiation, contrast, artifact from calcium

Anatomic vs. Functional Testing

Decision Framework

Prefer Functional If: Normal baseline ECG, able to exercise, good renal function, low BMI
Prefer CCTA If: Uninterpretable ECG, unable to exercise, intermediate risk, desire rule-out strategy
Consider CAC: Intermediate risk to refine probability before further testing

Coronary Artery Calcium (CAC)

IIaCAC scoring may be reasonable to modify pretest probability in symptomatic patients.

  • CAC 0: Very low risk; reassurance, medical therapy
  • CAC 1–99: Low risk; minimal CAD burden
  • CAC 100–399: Intermediate; consider stress testing or CCTA
  • CAC ≥400: High risk; aggressive therapy, further testing
CAC score of 0 has NPV ~99% in symptomatic patients; can reduce further testing need.

CCTA Indications and Interpretation

IIaCCTA reasonable as first-line in symptomatic intermediate-risk patients, especially unable to exercise or uninterpretable ECG.

  • 0% Stenosis: No CAD; medical therapy
  • 1–49%: Mild CAD; not flow-limiting
  • 50–69%: Moderate; functional testing or angiography
  • ≥70% or LM/3VD: Severe; angiography for revascularization
CCTA shows anatomy but not functional significance; 50–70% lesions may not cause ischemia. FFR or functional testing often needed.

Special Populations in Chest Pain Evaluation

Women

Unique Features

  • Atypical presentations: dyspnea, nausea, fatigue without chest pain
  • Higher mortality from ACS despite lower prevalence
  • Spontaneous coronary artery dissection (SCAD) higher in young women; consider in ACS with low CAD risk
  • Microvascular disease and vasospasm more common

Management

  • Maintain high suspicion for atypical presentations
  • Serial ECG and troponin mandatory
  • Consider coronary angiography with FFR if stress test abnormal but no obstructive CAD

Elderly (Age ≥65)

Key Challenges

  • Atypical presentations: syncope, dyspnea, or fatigue instead of chest pain
  • Multiple comorbidities (HF, renal disease, diabetes)
  • Limited exercise capacity; CCTA or stress echo often preferred
  • Higher baseline event risk; lower threshold for admission

Diabetes Mellitus

Considerations

  • Silent ischemia due to autonomic neuropathy; painless MI more common
  • More extensive and multivessel CAD
  • Elevated baseline troponin possible (prior MI or diabetic cardiomyopathy)

Approach

  • Lower threshold for ACS testing despite atypical symptoms
  • Serial troponins even with mild symptoms
  • Consider earlier revascularization if ischemia documented

Chronic Kidney Disease (CKD)

Troponin Interpretation

  • Chronically elevated troponin due to reduced clearance
  • Delta troponin (0-to-3h change) more predictive than absolute value
  • Rise/fall pattern indicates acute myocardial injury

Imaging Considerations

  • Contrast-induced nephropathy (CIN) risk; adequate hydration essential
  • Prefer functional imaging over CCTA if possible
  • If CCTA/angiography needed: minimize contrast, check renal function pre/post

Prior Revascularization

In-Stent Restenosis (ISR)

  • 5–10% BMS, <5% DES; presents with recurrent angina
  • Stress testing (caution: may not detect ISR in remote territory)
  • CCTA excellent for stent patency

Graft Failure (Post-CABG)

  • Vein graft occlusion or atherosclerosis in non-grafted vessels
  • Native vessel disease progression common

Observation Unit Protocol & Discharge Criteria

Observation Unit Approach

IChest pain observation units effective for low-to-intermediate risk patients; accelerate ACS rule-out and reduce unnecessary admission.

Typical 6–12 Hour Protocol

  • Serial ECGs (0, 1–3 hr, 6–12 hr)
  • Serial troponins per protocol (0/1h or 0/3h)
  • Continuous monitoring if high-risk features
  • Stress test or CCTA before discharge
  • Assess response to antianginal therapy

Safe Discharge Criteria

Safe to Discharge If ALL Present:

  • Low-to-intermediate pretest probability
  • Negative serial troponins (per protocol)
  • Normal or nonspecific stable ECG
  • No high-risk features (hemodynamic instability, recurrent angina)
  • Stress test OR CCTA negative, OR CAC 0
  • Reliable follow-up arranged within 72 hours
  • Patient able to recognize and respond to recurrent symptoms

Do Not Discharge If:

  • Ongoing ischemic symptoms despite therapy
  • Positive troponin
  • New or evolving ECG changes
  • Positive stress test or significant CCTA stenosis
  • Hemodynamic instability
  • High pretest probability without rule-out testing
  • Unreliable follow-up or inability to recognize symptoms

Outpatient Follow-Up

Clinical Pearls & Pitfalls

Pearl 1: Negative troponin in first 2–3 hours does NOT exclude ACS; serial measurements essential.
Pearl 2: Women present atypically; maintain high suspicion for dyspnea, nausea, fatigue without typical chest pain.
Pearl 3: Up to 5–10% of acute MIs have initially normal ECG; serial ECG and troponin critical.
Pearl 4: CAC score 0 has ~99% negative predictive value; reassurance and medical therapy appropriate in selected patients.
Pearl 5: Serial ECG (10–20 min intervals) if high clinical suspicion; dynamic changes increase diagnostic certainty.
Pearl 6: HEART score ≤3 identifies very low-risk patients safe for ED discharge with outpatient follow-up.
Pitfall 1: "Doesn't sound like ACS" — Atypical presentations are common; use systematic risk stratification, not clinical impression alone.
Pitfall 2: Type A Aortic Dissection — Severe back pain, pulse differential, mediastinal widening should trigger urgent TEE/CTA, not assume ACS.
Pitfall 3: Premature discharge without testing — Low pretest probability does not equal zero risk; stress testing or CCTA often warranted.
Pitfall 4: Confusing CAC with stenosis percent — High CAC does not indicate degree of stenosis; functional or anatomic testing still needed.
Pitfall 5: Over-interpreting CCTA stenosis — 50–70% lesions may not be flow-limiting; FFR or functional testing often necessary.
Pitfall 6: Ignoring renal function in CKD — Adequate hydration and contrast minimization essential to prevent contrast-induced nephropathy.

Related Risk Calculators

Use these validated tools for rapid risk quantification and clinical decision support in chest pain evaluation and ACS management.

HEART Score

Rapid ED assessment; predicts MACE in acute chest pain; identifies safe discharge candidates.

GRACE ACS Score

In-hospital and 6-month mortality prediction in acute coronary syndrome.

GRACE In-Hospital Mortality

Risk prediction for in-hospital death in ACS patients.

TIMI UA/NSTEMI Risk

Predicts 14-day death, MI, or recurrent angina in unstable angina/NSTEMI.

Wells PE Score

Clinical probability assessment for pulmonary embolism; guides D-dimer and imaging use.

Geneva Revised Score

Alternative PE probability assessment based on clinical and radiologic findings.

PESI Score

Pulmonary Embolism Severity Index; predicts 30-day mortality and complications in PE.

ASCVD Risk Calculator

10-year atherosclerotic CVD risk; guides primary prevention strategies.

MESA CAC Risk

Predicts presence and extent of coronary artery calcium; refines risk in asymptomatic patients.

Adult GFR Calculator

Estimates glomerular filtration rate; essential for renal dosing and risk assessment.

Creatinine Clearance (Cockroft-Gault)

Assesses renal function for drug and contrast dosing.

Corrected QT (QTc)

Calculates heart-rate corrected QT interval; assesses torsades de pointes risk.

PREVENT Calculator

Personalized Risk Estimation for Vascular Events and Nonfatal Outcomes; newer ASCVD risk assessment tool.

Disclaimer: This quick reference is educational. Always consult the full 2021 AHA/ACC Chest Pain Guideline and apply clinical judgment; risk stratification should incorporate institutional protocols and patient-specific factors.

Citation: Gulati M, Levy PD, Mukherjee D, et al. 2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR Guideline for the Evaluation and Diagnosis of Chest Pain. J Am Coll Cardiol. 2021;78(22):e187–e285. DOI: 10.1016/j.jacc.2021.07.053