This study investigates the effective power of angina pectoris after Quick-Acting Heart Reliever and isosorbide dinitrate interventing respectively the patients with moderate coronary stenosis for six months. At the same time, the studying will assess the plaque, myocardial blood-supplying,quality of life and observe the end point of the heart (including the myocardial revascularization, death and myocardial infarction). The purpose is to study the function of the blood-quickening stasis-transforming formula Quick-Acting Heart Reliever for moderate coronary stenosis lesions.

Blood-quickening stasis-transforming medicinal of Chinese medicinal can ameliorate clinical symptoms of coronary artery disease. Quick-Acting Heart Reliever is one of blood-quickening stasis-transforming medicinals to relieve angina pectoris in clinic and is especially benefit for the patients with moderate coronary stenosis who need not coronary revascularization only have medical treatment. But there is no randomized evidence that established the beneficial effects of blood-quickening stasis-transforming medicinals to treat moderate coronary stenosis lesions. This study is a randomized double-blind placebo-controlled clinical trials. A total of 120 consecutive participants with at least one moderate coronary stenosis lesion (diameter stenosis 50-75%) will be randomized to two groups: group 1(n =60) will receive Quick-Acting Heart and the placebo of isosorbide dinitrate, patients in group 2(n = 60) will receive isosorbide dinitrate and the placebo of Quick-Acting Heart for six months. The myocardial perfusion imaging and the coronary CT angiography will be used to evaluate the effective power of angina pectoris,myocardial blood-supplying，the quality and volume of the plaque, diameter stenosis after treating after 6 months and the end point of the heart (including death，myocardial infarction and myocardial revascularization which includes intracoronary stenting and coronary artery bypass grafting,) after 12 months. The purpose is to study the function of Quick-Acting Heart Reliever delaying percutaneous coronary intervention(PCI) for moderate coronary stenosis.

Inclusion Criteria:

• Male or female subjects 30-75 years of age
• Angina or CAD patient
• Diameter stenosis 50-75% in at least one main coronary artery (Confirmed by coronary arteriography or coronary CT angiography)
• Not received percutaneous coronary intervention(PCI)
• Heart blood stasis obstruction syndrome according to TCM syndrome differentiation
• Provide written informed consent.

Exclusion Criteria:

• Heart transplant or history of CABG or history of percutaneous transluminal coronary angioplasty (PTCA) with a drug-eluting stent.
• Left ventricular ejection fraction < 35%
• Acute myocardial infarction within 4 weeks prior to inclusion
• The contractive pressure > 160 mmHg or diastolic pressure >100 mmHg
• Severe valvular heart disease
• Insulin-dependent diabetes mellitus
• Serious heart, lung, liver, kidney and brain or other primary complications
• Mental patients
• Diagnosed or suspected tumor
• Allergic persons
• Pregnant, breastfeeding, or intends to become pregnant during the course of the study (females only)
• Patients not willing to or not able to give the informed consent to participate in the study
• The patients who are attending other clinical trial
• The person maybe loss for some reason such as work or life condition according to the investigator's judgement