This study adopted a randomized, double-blind, placebo-controlled, multicenter clinical design and compared the effects of Yangxinshi tablet and placebo on exercise tolerance in patients with chronic coronary syndrome (CCS).

The aim of the research is to find out if the addition of Yangxinshi tablets on the basis of conventional treatment can improve exercise tolerance of patients with chronic coronary syndrome (CCS), improve quality of life and mental health. A total of 120 qualified CCS patients were randomly divided into two groups. In addition to conventional treatment, the experimental group was given Yangxinshi tablets (3 tablets/time and 3 times/day), and the control group was given Yangxinshi tablet simulants (3 tablets/time and 3 times/day). The treatment period was 24 weeks. The primary endpoints were metabolic equivalents (METs), and peak oxygen uptake measured by cardiopulmonary exercise testing after 24 weeks of treatment.

Inclusion Criteria:

All the following criteria must be met to participate in the study:

1. Meet the diagnostic criteria for CCS in Western medicine; stable coronary heart disease (CHD) with a degree of coronary stenosis ≥50% by angiography or computed tomography angiography (CTA) (including patients with more than 1 year of revascularization)
2. Meet the TCM standard of Qi deficiency and blood stasis syndrome
3. MET < 5 measured by cardiopulmonary exercise test (treadmill)
4. Age between 18 and 75 years (including both age limits), with no limitation on sex
5. Understanding and voluntarily signing the written informed consent

Exclusion Criteria:

All the following criteria must not be met to participate in the study:

1. Individuals with lower extremity dysfunction, intermittent claudication or severe leg pain who cannot participate in cardiopulmonary exercise tests
2. Individuals with acute coronary syndrome within 1 month after percutaneous coronary intervention (PCI) or within 3 months after coronary artery bypass grafting (CABG)
3. Individuals with serious primary diseases related to the liver, kidney, and hematopoietic system, acute infectious diseases, and mental illness and individuals with other diseases who are not suitable for cardiopulmonary exercise tests
4. Individuals with a revascularization plan within a month
5. Individuals with left main stenosis ≥50% or proximal left anterior descending (LAD) diameter stenosis ≥90% without PCI or CABG
6. Individuals with absolute and relative contraindications to cardiopulmonary exercise testing (please see Appendix 11 for details)
7. Individuals with New York Heart Association (NYHA) cardiac function class III and IV
8. Individuals with acute cerebrovascular disease
9. Individuals with uncontrolled hypertension: systolic blood pressure ≥ 160 mmHg and diastolic blood pressure ≥ 100 mmHg
10. Individuals found to be in a state of severe anxiety and depression as determined using the GAD-7 and PHQ-9
11. Individuals with allergies or abnormal drug reactions to the test drugs
12. Women of childbearing age who are pregnant or breastfeeding, plan to get pregnant within six months, have a positive pregnancy test, and cannot take effective contraceptive measures during the study period
13. Individuals who have regularly taken YTs, Chinese herbal decoctions or proprietary Chinese medicines with similar curative effects within the past 7 days (please refer to Appendix 12 for the names of proprietary Chinese medicines)
14. Individuals who have participated in other clinical trials within the past 3 months
15. Individuals unsuitable for the clinical trials, as determined by the researchers