Yiqi Fumai Lyophilized Injection for Improving Exercise Tolerance in Chronic Heart Failure: Protocol for a Prospective Cohort Study.

Background: High mortality and prevalence rates are hallmarks of chronic heart failure (CHF). Patients frequently have a much lower quality of life as a result of diminished exercise tolerance. Chinese guidelines have recommended Yiqi Fumai lyophilized injection (YQFM) for the treatment of heart failure, although there is currently inadequate evidence to support its effectiveness in increasing exercise tolerance in these patients. Objective: The purpose of this cohort study is to examine the relationship between the improvement of exercise tolerance in patients with CHF and the addition of YQFM to guideline-directed medical therapy. Methods: In total, 216 hospitalized patients with CHF with New York Heart Association (NYHA) functional classes II-IV were to be enrolled in the prospective, observational cohort trial design. The participants were divided into a YQFM group (exposed group: n=144) and a non-YQFM group (nonexposed group: n=72) at a 2:1 ratio based on real clinical medication and patient preference. Standard guideline-directed medical therapy was administered to both groups; however, the YQFM group also got a 10-day YQFM exposure. The change in metabolic equivalents measured by the Veterans Specific Activity Questionnaire was the main outcome. The 6-minute walk distance, Kansas City Cardiomyopathy Questionnaire score, NYHA functional class, N-terminal pro-B-type natriuretic peptide levels, and echocardiographic parameters were among the secondary objectives. Traditional Chinese medicine syndrome scores and the frequency of hard clinical occurrences were the exploratory objectives. A linear mixed-effects model was used to examine repeated measurement data, and propensity score weighting was used to account for baseline confounding variables. Results: The first patient was registered in June 2024, and all 216 patients had been recruited and followed up with by December 2025. Data cleaning and statistical analysis began in January 2026, with final results scheduled to be published in the autumn of 2026. Conclusions: This study, using a prospective cohort design, intends to offer high-quality, real-world evidence for the use of YQFM in cardiac rehabilitation for heart failure. This will aid in the optimization of preventative and treatment strategies for CHF that combine traditional Chinese and Western medicine, giving an objective basis for enhancing patients' long-term quality of life.