This is a clinical study to evaluate the effectiveness and explore the possible working mechanisms of a traditional Chinese herbal formula called Yixin Powder. The study focuses on patients with stable angina pectoris (chest pain) caused by coronary heart disease (CHD), who are diagnosed with a specific Chinese medicine pattern known as "qi deficiency and blood stasis," based on the "weak pulse at yang and wiry pulse at yin" theory.

The study hypothesizes that adding Yixin Powder to standard Western medication will be beneficial for these patients. To test this, participants diagnosed with this condition will be randomly assigned to one of two groups. One group will receive standard medication alone, while the other group will receive the same standard medication plus Yixin Powder. The effects of the treatments will be compared between the two groups.

Inclusion Criteria:

• Diagnosis of CHD-induced stable angina pectoris according to Western medicine diagnostic criteria；
• Diagnosis of qi deficiency and blood stasis pattern according to TCM pattern differentiation;
• Age between 40 and 70 years, regardless of sex;
• Stable vital signs and normal liver and renal function before enrollment;
• Angina severity graded between I and III;
• Voluntary participation with signed informed consent.

Exclusion Criteria:

• Uncontrolled severe hypertension (BP ≥180/110 mmHg);
• Severe comorbid conditions involving major organs or systems, including heart, brain, liver, or kidneys;
• Known allergy to, or intolerance of, any of the study medications; (3) Presence of psychiatric disorders;
• Requirement for long-term use of medications that could interfere with study outcomes;
• Coexisting infectious diseases.