What is the accuracy percentage of stress electrocardiogram (ECG) in detecting coronary artery disease?

Accuracy of Stress ECG in Detecting Coronary Artery Disease

Stress ECG has a modest diagnostic accuracy for detecting coronary artery disease with a sensitivity of approximately 45-50% and specificity of 70-77%, making it significantly less accurate than stress imaging modalities. 1

Diagnostic Accuracy of Stress ECG

• Standard exercise ECG testing has a sensitivity of only 45-50% and specificity ranging from 70-77% for detecting obstructive coronary artery disease (CAD) 1
• When studies are designed to minimize workup bias, the sensitivity of exercise ECG is even lower at 45% with a specificity of 85% 1
• The diagnostic accuracy of stress ECG is particularly limited in women, with lower sensitivity compared to men 1
• In "real-world" clinical settings, stress ECG demonstrates sensitivity of 47%, specificity of 53%, positive predictive value of 51%, and negative predictive value of 49% 2

Factors Affecting Stress ECG Accuracy

• Multiple factors influence the accuracy of exercise ECG testing, including:

  • Inability to achieve maximal exercise levels 1
  • Resting ECG abnormalities (LV hypertrophy, LBBB, ventricular-paced rhythm) 1
  • Medications such as digitalis that can produce false positive findings 1
  • Anti-ischemic therapies that can reduce heart rate and myocardial workload, leading to false negative results 1

• Patients who are candidates for exercise ECG must:

  • Be able to exercise adequately 1
  • Have an interpretable ECG (normal 12-lead ECG or minimal resting ST-T-wave abnormalities <0.5 mm) 1

Comparison with Stress Imaging Modalities

• Stress echocardiography has significantly better diagnostic performance:

  • Exercise stress echocardiography: sensitivity 80-85%, specificity 77-89% 1
  • Dobutamine stress echocardiography: sensitivity 79-83%, specificity 84-90% 1
  • Overall diagnostic accuracy of stress echocardiography is approximately 85% 3

• Nuclear myocardial perfusion imaging also outperforms stress ECG:

  • Exercise stress SPECT: sensitivity 73-92% 1
  • Vasodilator stress SPECT: sensitivity 90-91% 1
  • MIBI-SPECT has the highest sensitivity (87%) but lower specificity (70%) compared to stress echocardiography 4

Gender Differences in Stress ECG Performance

• The diagnostic accuracy of stress ECG is generally lower in women compared to men 1
• In women, exercise echocardiography has improved diagnostic sensitivity and specificity compared with exercise ECG alone 1
• For women with suspected ischemic heart disease, stress echocardiography has a diagnostic sensitivity of 79% (95% CI, 74%-83%) and specificity of 83% (95% CI, 74%-89%) 1
• Dobutamine stress echocardiography in women has reported sensitivities ranging from 75% to 93% and specificities from 79% to 92% 1

Recent Advances in Stress ECG

• Artificial intelligence approaches show promise for improving stress ECG performance:
  • A recent transformer-based AI model demonstrated sensitivity of 93.6%, specificity of 93.2%, and overall accuracy of 93.4% in detecting CAD 5
  • This represents a potential absolute increase in sensitivity of 40.9% in women and 44.6% in men compared to conventional interpretation 5

Clinical Implications and Recommendations

• Due to its limited sensitivity, a negative stress ECG cannot definitively exclude hemodynamically significant CAD, especially in high-risk patients 6

• For patients with intermediate to high pretest probability of CAD, stress imaging modalities are preferred over standard exercise ECG 1

• Exercise ECG remains useful as a first-line test for patients with:

  • Low to intermediate pretest probability of CAD 1
  • Normal resting ECG 1
  • Ability to exercise adequately 1
  • No digoxin therapy 3

• When stress ECG results are inconclusive or equivocal, additional testing with stress imaging is recommended 1, 6