HEART Score for Excluding ACS in the Emergency Department
The HEART score is a validated 5-component risk stratification tool (History, ECG, Age, Risk factors, Troponin) that safely identifies low-risk chest pain patients (score 0-3) who can be discharged from the ED with less than 2% risk of 30-day major adverse cardiac events (MACE), outperforming older tools like TIMI and GRACE scores. 1, 2, 3, 4
Components and Scoring System
The HEART score assigns 0-2 points for each of five components, creating a total score range of 0-10 2, 5:
History: Highly suspicious presentations (exertional chest pain relieved by rest, associated symptoms like orthopnea, nausea, or "indigestion") receive 2 points; moderately suspicious receive 1 point; non-suspicious receive 0 points 2, 6
ECG: Significant ST-segment depression receives 2 points; nonspecific repolarization abnormalities receive 1 point; completely normal ECG receives 0 points 2, 5
Age: Patients ≥65 years receive 2 points; age 45-64 receives 1 point; <45 years receives 0 points 2
Risk factors: Three or more traditional cardiovascular risk factors (hypertension, hyperlipidemia, diabetes, smoking, family history, obesity) receive 2 points; 1-2 risk factors receive 1 point; none receive 0 points 2, 5
Troponin: Levels >3× the upper limit of normal receive 2 points; 1-3× normal receive 1 point; normal receives 0 points 2
Risk Stratification Categories
The American College of Cardiology recommends three distinct risk categories 2, 5:
Low risk (0-3 points): <1-2% risk of 30-day MACE, supporting immediate discharge without further cardiac testing 2, 3, 4
Intermediate risk (4-6 points): 16.6% risk of MACE, requiring observation with serial troponins or stress testing 4
High risk (7-10 points): 50-65% risk of MACE within 6 weeks, mandating immediate admission with cardiology consultation and likely cardiac catheterization 6, 4
Integration with High-Sensitivity Troponin Protocols
The American Heart Association recommends combining the HEART score with serial high-sensitivity troponin measurements at 0 and 2 hours for optimal risk stratification 2, 5. When both measurements are below the 99th percentile with a HEART score of 0-3, the false negative rate drops to 0.8-0.9% for 30-day MACE 1. This accelerated diagnostic protocol safely decreases hospital admissions while maintaining acceptable miss rates of 1-2% 2.
Performance Compared to Other Risk Scores
The HEART score demonstrates superior discrimination compared to historical tools 1, 3, 4:
C-statistic of 0.83 versus TIMI (0.75) and GRACE (0.70), with statistically significant superiority (p<0.0001) 3, 4
The American College of Radiology notes that older scores like TIMI, GRACE, and PURSUIT are being replaced by the HEART score, which was specifically designed for ED chest pain evaluation without a diagnosis of ACS 1
International consensus guidelines from 2010 explicitly state that scoring systems derived from in-patient populations (TIMI, Goldman Criteria) are not appropriate for ED use and should not be used to select patients for safe discharge 1
Critical Implementation Pitfalls
Serial ECG monitoring is crucial when the initial ECG is nondiagnostic, as dynamic changes may emerge that alter risk stratification 2, 5. The HEART score may be less accurate in very early presenters (within 2-3 hours of symptom onset) where troponin elevation hasn't yet occurred 2.
A 2021 prospective study found only moderate agreement (78%, kappa 0.48) between clinician-generated and research-generated HEART scores, with the lowest agreement in the History (72%) and ECG (85%) components 7. This highlights the subjective nature of certain components and the need for standardized interpretation.
Do not attribute troponin elevation solely to demand ischemia or hypertensive emergency without excluding Type 1 MI through coronary angiography, particularly when troponin shows a rising pattern 6. Patients with exertional patterns, rising troponin, and ECG changes require revascularization evaluation regardless of blood pressure 6.
Clinical Application Algorithm
For patients presenting with chest pain 2, 5, 6:
Calculate HEART score immediately after obtaining initial ECG and troponin results
Score 0-3: Discharge home with outpatient cardiology follow-up if needed; no further inpatient cardiac testing required
Score 4-6: Admit for observation with repeat troponin at 2-3 hours, or proceed to stress imaging (PET/SPECT, CMR, or stress echocardiography) for known CAD patients
Score 7-10: Immediate hospital admission with cardiology consultation; proceed to invasive coronary angiography
Borderline scores (3-4): Use shared decision-making and consider repeat troponin measurement before final disposition
The American College of Emergency Physicians endorses achieving a miss rate of 1-2% for 30-day MACE, which the HEART score reliably achieves when properly applied 2. However, avoid overreliance on a single parameter while ignoring clinical context 5.