What is the role of the HEART (History, Electrocardiogram, Age, Risk factors, and Troponin) score in assessing patients with acute chest pain?

HEART Score for Acute Chest Pain Assessment

Direct Recommendation

The HEART score should be used as a validated clinical decision pathway to risk-stratify emergency department patients with acute chest pain into low-risk (0-3 points), intermediate-risk (4-6 points), and high-risk (≥7 points) categories, with low-risk patients eligible for safe discharge without admission or urgent cardiac testing. 1

Components and Scoring System

The HEART score consists of five equally weighted components, each scored 0-2 points 1:

• History: Highly suspicious (2 points), moderately suspicious (1 point), slightly suspicious (0 points) 1
• ECG: Significant ST-segment depression (2 points), nonspecific abnormalities (1 point), normal (0 points) 1
• Age: >65 years (2 points), 45-65 years (1 point), <45 years (0 points) 1
• Risk factors: ≥3 risk factors (2 points), 1-2 risk factors (1 point), no risk factors (0 points) 1
• Troponin: >3× normal limit (2 points), 1-3× normal limit (1 point), ≤normal limit (0 points) 1

Risk Stratification and Clinical Actions

Low-Risk Patients (HEART Score 0-3)

Patients with HEART scores 0-3 have <1% risk of 30-day major adverse cardiac events (MACE) and can be safely discharged from the emergency department without admission or urgent cardiac testing. 1, 2

• The low-risk category identifies approximately 28-33% of chest pain patients for safe discharge 3, 4
• Negative predictive value for 30-day MACE ranges from 98.1-99.7% 5, 3, 4
• Serial troponin measurements at 0 and 3 hours should accompany the HEART score assessment 1

Intermediate-Risk Patients (HEART Score 4-6)

Intermediate-risk patients require observation unit management with serial troponin testing and consideration for stress testing or coronary CT angiography. 1

• This group comprises approximately 70% of chest pain presentations 5
• Management in an observation unit is reasonable to shorten length of stay and lower costs compared to inpatient admission 1
• Transthoracic echocardiography is recommended as a rapid bedside test to evaluate ventricular function and wall motion abnormalities 1

High-Risk Patients (HEART Score ≥7)

High-risk patients should undergo invasive coronary angiography. 1

• This category has a 43.1% risk of 30-day MACE 3
• Patients with new ischemic ECG changes, troponin-confirmed acute myocardial injury, or hemodynamic instability should be designated as high risk 1

Integration with High-Sensitivity Troponin Testing

The HEART Pathway combines the modified HEART score (without the troponin component initially) with serial high-sensitivity troponin measurements to improve sensitivity and negative predictive value. 1

• Serial troponin measurements should occur at 1-3 hours for high-sensitivity assays or 3-6 hours for conventional assays 1
• For patients with symptom onset >3 hours before arrival, a single high-sensitivity troponin below the limit of detection can reasonably exclude myocardial injury 1
• The 0/1h and 0/2h algorithms are superior to the 0/3h algorithm for rule-out performance 1

Comparative Performance

The HEART score demonstrates superior discriminative ability compared to the TIMI score in emergency department populations, with C-statistics of 0.83 versus 0.75. 3

• The American College of Emergency Physicians recommends both HEART and TIMI scores for predicting 30-day MACE 1
• HEART score achieves 100% sensitivity for MACE when applied by clinicians, though specificity is only 27.8% 6
• The GRACE score remains superior for predicting in-hospital mortality in confirmed ACS patients 7

Critical Implementation Considerations

Subjective Component Limitations

The history and ECG components are subjective, leading to only moderate inter-rater agreement (kappa 0.48) between clinicians and researchers. 1, 6

• History component shows the lowest agreement (72%; weighted kappa 0.14) 6
• ECG interpretation agreement is 85% (weighted kappa 0.4) 6
• This subjectivity can result in clinicians over-scoring patients compared to standardized research assessments 6

Timing-Dependent Accuracy

Patients presenting very early (<3 hours from symptom onset) may have falsely reassuring low HEART scores because troponin elevation has not yet occurred. 1, 2

• Serial troponin measurements are essential in early presenters to avoid missing evolving myocardial infarction 1
• Up to 26% of patients with acute MI may be on the downslope of the troponin curve and not manifest falling patterns over short periods 1

Acceptable Miss Rate

The acceptable miss rate for emergency department physicians is 1-2% for 30-day MACE, which the HEART score achieves in low-risk patients. 1, 2

• In validation studies, 1.7% of low-risk patients (HEART score ≤3) experienced MACE 3
• Four patients with low research HEART scores had MACE in one prospective validation study 6

Algorithmic Implementation

Institutions should implement a standardized clinical decision pathway incorporating the HEART score with their specific troponin assay protocol. 1

1. Calculate HEART score on all non-STEMI chest pain patients 1
2. For HEART score 0-3 with negative serial troponins: discharge home 1, 2
3. For HEART score 4-6: observation unit with stress testing or anatomic imaging 1
4. For HEART score ≥7: invasive coronary angiography 1

The HEART score should not be used as the sole determinant of disposition but rather integrated with clinical judgment, serial ECGs, and cardiac biomarkers. 7, 6