The NIA algorithm is similar to the traditional 12-lead ECG equipment. By analyzing patient data, NIA algorithm provides more detailed results compared to traditional 12-lead ECG. Patients with suspected coronary artery disease are conventionally diagnosed and treated by cardiac catheterization. However, cardiac catheterization is invasive procedure. Unless clinical diagnosis is evident before cardiac catheterization, a treadmill exercise test, a nuclear medicine myocardial perfusion test, or a multi-direction coronary CT angiogram is usually performed to increase the accuracy of diagnosis. But these examinations are not accessible to all patients, and are time-consuming and costly.

In this project, the investigators hope to compare the data collected under this new technology of NIA algorithm with results from final diagnoses of cardiac catheterization. As the NIA algorithm is a fast and less costly, if it provides more sensitivity and specificity than does exercise ECG, nuclear myocardial perfusion test, and high-resolution coronary CT angiogram, it will expedite diagnosis for patients with coronary artery disease.

Inclusion Criteria:

• patient with acute coronary syndrome who accepted percutaneous coronary intervention

Exclusion Criteria:

• no percutaneous coronary intervention

myocardial Ischemia