Background: Heart failure is the severe and terminal stage of various heart diseases, which is characterized by high morbidity, mortality and readmission. There are few studies on the relationship between XinKang-I(XK-I) and chronic heart failure.

Objective: To explore the relationship between XK-I and chronic heart failure. Methods/design: The trial is a single-center, single-blind, randomized study (1:1). It will recruit 110 patients with chronic heart failure who syndrome of qi deficiency yang deficiency and blood stasis. The intervention group will receive not only Western medicine, but also XK-I. The primary end points will be the changes in oxygen consumption volume of anaerobic threshold (VO2AT), maximum oxygen volume uptake (VO2max), and 6-minute walking distance after 8 weeks of treatment. Both groups will receive 8 weeks of treatment.

Ethics and dissemination: Ethical approval was granted by Ethics Committee of Dongguan TCM Hospital. Results will be disseminated via peer-reviewed publications and presentations at international conferences.

Inclusion Criteria:

1. History of CHF or clinical findings of CHF for more than 3 months. CHF was diagnosed in accordance with the European Society of Cardiology's 2021 Guidelines for the Diagnosis and Treatment of Acute and Chronic Heart Failure.
2. Patients ranged in age from 18 to 85.
3. Cardiac function was graded at grade II-IV (New York Heart Association functional class).
4. Patients who had not used traditional Chinese medicine for treating heart failure within 1 week before enrollment;
5. Written informed consent will be obtained.

Exclusion Criteria:

1. acute cardiac insufficiency, acute myocarditis, severe valvular heart disease, malignant arrhythmia, obstructive cardiomyopathy, pericardial tamponade, constrictive pericarditis or acute coronary syndrome
2. severe lung, liver or kidney dysfunction
3. nervous and hematopoietic system
4. malignant tumors
5. hemodynamic nstability
6. pulmonary embolism
7. severe infection
8. pregnant or lactating
9. refusal to provide written informed consent for this study