This record covers the prospective interventional component of a broader integrated research program. The registered component is a multicenter, prospective, open-label, single-arm performance-goal study in 100 hospitalized adults aged 40 to 80 years with stable chronic heart failure with reduced ejection fraction caused by coronary heart disease, NYHA class II or III symptoms, left ventricular ejection fraction of 40% or less, NT-proBNP of at least 450 pg/mL, and Qi and Yin deficiency syndrome. All participants will receive Yiqi Fumai lyophilized injection in addition to stable guideline-directed medical therapy. The study drug will be administered as 8 vials once daily, diluted in 250 mL of 0.9% sodium chloride, by intravenous infusion at 35 to 40 drops per minute for a planned 10 days. Clinically necessary discharge, transfer, treatment modification, or rescue therapy will not be delayed to complete study procedures. The co-primary outcomes are Day 10 KCCQ-CSS response and Day 10 NT-proBNP response, both measured before the Day 10 infusion. KCCQ-CSS response is generally defined as an increase of at least 5 points from baseline; a participant with a baseline score of at least 95 who remains at least 95 is also a responder. NT-proBNP response is defined as a decrease of at least 30% from baseline using paired central-laboratory results. Death, heart-failure rehospitalization, major rescue therapy, or inability to complete assessment because of worsening heart failure before Day 10 is counted as nonresponse. The KCCQ-CSS performance goal is p0=50% with p1=65%, and the NT-proBNP performance goal is p0=45% with p1=60%. Testing follows a prespecified fixed order and intersection-union principle; both outcomes must pass for overall co-primary success. Follow-up assessments occur at Day 30 and Day 90. A prespecified subgroup of 50 participants, randomly selected within center and NYHA strata, will undergo paired Day 0 and Day 10 multi-omics sampling. The broader protocol also includes a separate retrospective comparative cohort of 200 patients for external triangulation and economic modeling; those retrospective patients are not part of the enrollment or design entered in this interventional record.