This clinical trial is to test if a 28-channel ECG (MECG) system would efficiently differentiate the patients suspected to have CAD or ACS with acceptable sensitivity and specificity, and optimize this portable self-built-in multichannel ECG recorder system with various algorithms. The 28-channel ECG (MECG) system is a multi-channel real-time cardiovascular performance evaluation system. The system mainly includes: a multi-channel ECG signals measurement unit, a multi-channel ECG signals processing device, and an ECG signals reconstruction unit. The method uses a MAMA-END algorithm, to mark ECG signals to replace the original ECG signal and to extract and reconstruct a first signals having QRS wave, and a second signal having T wave; then method detects and marks the start of Q wave and the end of T wave on the first signal and the second signal. Therefore, the method is able to determine and evaluate if a patient does have cardiovascular disease, and to locate the lesion positions of a patient having cardiovascular disease.

We shall conduct this prospective clinical study to define the specific patterns of multichannel ECG change in adults with suspected CAD or ACS. For multichannel ECG (M-ECG) examination, the signal will be recorded with a Self-built-in ECG recorder. However, the examinations, diagnosis, medications, or procedures for the patients will only depend on the decision made by the primary care physicians through the traditional ways. The M-ECG results will not be used by the primary physicians for any diagnosis or decision-making of the patients. That is, the final diagnosis of CAD will be made with coronary angiography and the final diagnosis of ACS will be made with the traditional criteria (symptoms, traditional ECG changes, and cardiac enzyme changes).

Multichannel ECG Study The Self-built-in M-ECG recorders have passed the electrical security test. Multichannel ECG study will be performed under the approval of the Institutional Review Board. Before ECG examination, subjects will receive adequate orientation of the examination procedures and will complete inform consent.

During the ECG recording ,the patent will lie down flat on the bed, and 4 ECG leads with commercially available pads (Covidien Kendall ECG electrodes Medi-trace 200) will be applied on the 4 extremities, respectively. Using xyphoid process as a right lower reference point, a 18cm x 18cm patch integrated with 24 evenly distributed electrode pads (Covidien Kendall ECG electrodes Medi-trace Mini 100) will be applied on the left chest wall . Then, the ECG signals will be recorded through the self-built-in ECG recorders. The overall period for recording will be around 10 minutes.

The postprocessing and analysis of the ECG data will be performed with a PC computer by an analyzer without prior knowledge of the patient's clinical information. After ECG data is acquired, the analytic software will provide an electrical mapping of QTc dispersion (SIQTC).

Inclusion Criteria:

1. >20 years
2. Patients admitted for cardiac catheterization examination due to clinically suspected coronary artery disease (CAD): Those who have exertional chest pain and positive ischemic change by stress test, highly suspected lesions on non-invasive images, or very typical chest pain symptoms.
3. Patients visiting ER due to suspected ACS: Those who have sudden onset of chest pain or shortness of breath.

Exclusion Criteria:

1. Wound over the fore chest
2. Life-threatening malignancy in 5 years
3. Treatment with immunosuppressive agents
4. Any unfeasible condition or situation from the opinion of the primary care physicians (ex.

critical condition needing emergency treatment or intervention, cardio pulmonary cerebral resuscitation, etc.)