What is the probability of detecting myocardial ischemia with an electrocardiogram (ECG)?

The accuracy rate of ECG in diagnosing myocardial ischemia is around 80%, indicating that ECG is one of the effective methods for detecting myocardial ischemia, although not 100% accurate. ECG can reflect changes in the heart's electrical activity during myocardial ischemia, such as characteristic findings including ST-segment depression and T-wave inversion. However, due to the complexity and variability of myocardial ischemia and the inherent limitations of ECG—for instance, its possible insensitivity to transient episodes or mild myocardial ischemia—other diagnostic tools are sometimes needed to confirm the diagnosis. These may include echocardiography, exercise stress ECG, 24-hour Holter monitoring, and even coronary CTA or coronary angiography. ECG plays an important role in diagnosing myocardial ischemia, but its accuracy can be influenced by multiple factors and should be interpreted comprehensively.