This study is a prospective, multicentre, randomized, open-label, blinded-endpoint clinical trial to evaluate the efficacy and safety of Yangxinshi tablets in the treatment of patients with chronic coronary syndrome (CCS).

This study plans to enrol 1200 CCS patients. A central randomized control group will be set up. The experimental and control groups will be populated at a 3:1 ratio. In addition to basic medication, the experimental group will be given Yangxinshi tablets (three tablets each time, three times a day); the control group will be given basic medication only. The treatment period is 24 weeks. The primary efficacy indicator is the 6-minute walking distance (6MWD).

Inclusion Criteria:

1. age 18-75 years;
2. CCS patients in stable condition and clearly diagnosed by coronary artery imaging (at least one vessel stenosis ≥ 50%): stable angina, ischaemic cardiomyopathy, asymptomatic or stable symptoms, occult coronary heart disease, acute coronary syndrome (ACS), or >3 months after coronary revascularization;
3. moderately to severely limited exercise tolerance: the maximum 6MWD is < 450 m, or the metabolic equivalent (MET) as measured by treadmill cardiopulmonary exercise testing is < 5 METs;
4. voluntary participation and signing of informed consent.

Exclusion Criteria:

1. absolute or relative contraindications for the treadmill cardiopulmonary exercise test or 6-minute walk test (6MWT);
2. serious primary diseases, mental diseases, or malignant tumours that affect lifespan;
3. pregnancy, intended or suspected pregnancy, miscarriage, breastfeeding, or delivery in the last 6 months;
4. subjects not suitable for this study in the opinion of the researchers, such as subjects who are participating in other drug clinical trials or intervention studies.