Although some important progresses were made in the field of the meridian research, no breakthroughs have been achieved. Besides,there are some problems in meridian researches. Particularly, previous research of meridian phenomenon involved lots of subjective elements and outcomes.Researches that use modern scientific techniques to investigate the biological characteristics of meridian phenomenon are urgently needed. Therefore, this study is designed to assess the metabolic characteristics of meridian phenomenon for the Heart and Lung meridians by using near infrared spectroscopy. Thus, the biological characteristics of meridian phenomenon could be presented objectively in a scientific methodology.

This study will include 40 patients diagnosed with chronic stable angina pectoris (CSAP) and 40 healthy volunteers. Near infrared spectroscopy will be adopted to assess the metabolic characteristics of meridian phenomenon for Heart and Lung meridians in the physiology/pathological state. In addition, by comparing the metabolic characteristics in the acupoints along the Heart and Lung meridians, the relative specificity of the two meridians will also be investigated.

Primary outcomes will be regional oxygen saturation (rSO2). Furthermore, this study will build standardized techniques and schemes for detecting the metabolic characteristics of meridian phenomenon for Heart and Lung. The results of this study could also provide scientific foundation for traditional meridian theories.

Inclusion Criteria:

Inclusion criteria for CSAP

1. Patients should meet the diagnostic criteria of coronary heart disease, which includes the following items: 1)confirmed old myocardial infarction (MI), or a history of percutaneous coronary intervention(PCI), or coronary artery bypass grafting; 2)50% or more luminal stenosis in at least one coronary artery or major branch segment confirmed by coronary angiogram or CT angiography; 3) myocardial ischemia indicted by exercise stress radionuclide myocardial imaging; 4) treadmill exercise testing is positive (for male patients);
2. Patients should meet the diagnostic criteria of CSAP and the Canadian Cardiovascular Society(CCS) classification for CSAP is level II or III;
3. The medical history of angina pectoris ≥3 months, with at least 2 episodes per week in the last month;
4. 35 ≤ age ≤65 years, male or female;
5. Patients have clear consciousness and could communicate with others normally;
6. Patients could understand the full study protocol and have high adherence. Written informed consent is signed by themselves or their lineal kin.

Inclusion criteria for health volunteers

1. Healthy volunteers who could provide a recent (in the past 3 month) medical examination report to confirm they have not any cardiovascular, respiratory, digestive, urinary, hematological, endocrine and neurological disease;
2. 35 ≤ age ≤65 years, male or female;
3. Participants have clear consciousness and could communicate with others normally;
4. Participants could understand the full study protocol and have high adherence .Written informed consent is signed by themselves or their lineal kin.

Exclusion Criteria:

Exclusion criteria for CSAP

1. Patients with acute coronary syndrome (including acute myocardial infarction and unstable angina) and severe arrhythmias (such as severe atrioventricular block, ventricular tachycardia, supraventricular tachycardia, frequent premature beats and premature ventricular contraction);
2. Patients' chest pain is caused by valvular heart disease, hypertrophic cardiomyopathy and dilated cardiomyopathy;
3. Patients' chest pain is caused by non-cardiac disease (such as severe neurosis, climacteric syndrome, cervical spondylosis, and esophageal/pulmonary/chest wall lesions);
4. Patients have concomitant conditions of lung diseases, such as COPD;
5. Patients have serious concomitant conditions and and fail to treat them effectively, such as diseases of the digestive, urinary, respiratory, hematological and nervous system;
6. Patients have mental illness, severe depression, alcohol dependence or history of drug abuse;
7. Pregnant or lactating patients;
8. Patients are participating in other trials.

Exclusion criteria of health volunteers

1. Participants have sudden severe diseases during the trial, such as cardiovascular diseases, liver diseases, kidney diseases, urinary diseases and hematological diseases.
2. Participants have mental illness, severe depression, alcohol dependence or history of drug abuse;
3. Pregnant or lactating participants ;
4. Participants are participating in other trials.

40 patients with chronic stable angina pectoris (CSAP) and 40 healthy volunteer.