A TSHRN1201 Sub-study-To Evaluate the Effects of add-on Ranolazine on Exercise Tolerance and Angina Frequency

Inclusion Criteria: 1. Male or female patients aged ≥ 20 years old. 2. A minimum 3-month history of stable angina. 3. Patients with diagnosis of coronary artery disease (CAD) via at least one of the following criteria: * Angiographic evidence of ≥ 50% stenosis of ≥ 1 major coronary artery; * CT angiographic evidence of ≥ 50% stenosis of ≥ 1 major coronary artery; * History of previous myocardial infarction (MI)\*; \*Previous MI history of patients has to be occurred and diagnosed at least 2 months prior entering this study. * A stress-induced reversible perfusion defect identified by radionuclide or echocardiographic imaging. 4. Patients present with the symptoms of stable angina after withdrawn from other antianginal drugs and given the required background therapy for at least 5 days will be qualified for entering this study and performing 1st ETT qualifying test. 5. Patients developed exercise-induced ECG ischemia during two qualifying exercise treadmill tests. The difference between twotests should be ≤ 20% of the longer test or ≤ 1 minute. 6. Willing and able to provide a written informed consent. Exclusion Criteria: 1. Factors that might compromise ECG or ETT interpretation. * Patients with resting ST-segment depression ≥ 1mm in any lead. * Left bundle-branch block. * Patients implanted with pacemaker. * Patients under Digitalis therapy. 2. Patients with family history of (or congenital) long QT syndrome. 3. Patients with congenital heart disease. 4. Patients with uncorrected valvular heart disease. 5. Patients with unstable angina, or MI, or coronary revascularization procedure ≤ 2 months prior enter this study. 6. Female who is pregnant/lactating or planning to be pregnant, or female of childbearing potential\* who is not using medically recognized method of contraception. \*Other than those who have been surgically sterilized (defined as having undergone hysterectomy or bilateral oophorectomy or bilateral salpingectomy; tubal ligation alone is not considered sufficient) or one year post-menopausal. 7. Patients are under any one of the following conditions: * New York Heart Association (NYHA) Class III or Class IV congestive heart failure (CHF); * QTc \> 450 msec at screening; * Active myocarditis, pericarditis, hypertrophic cardiomyopathy; * Uncontrolled hypertension (defined as SBP \> 180 mmHg). Voltage criteria for left ventricular hypertrophy in the absence of repolarization abnormalities will not be exclusion criteria. 8. Use of any investigational product ≤ 4 weeks prior to screening. 9. Patients with severe hepatic disease (e.g., liver cirrhosis). 10. Patients with impaired renal function (defined as serum Cr \>1.5 mg/dl). 11. Patients with any condition or disease which is considered not suitable for this study by investigator.