Effect of Yangyin Shuxin Decoction on Exercise Capacity in Patients with Heart Failure with Normal Ejection Fraction: Rationale and Design of a Randomized Controlled Trial

Abstract Background The incidence of heart failure with normal ejection fraction (HFNEF) is increasing yearly, accounting for approximately half of all heart failure cases. Even after standardized treatment, the patient's prognosis is not good. Therefore, it is necessary to explore new treatment methods for HFNEF. Yangyin Shuxin Decoction, a traditional Chinese medicine prescription from our clinical experience in the treatment of HFNEF, has a potential cardioprotective effect. Preliminary clinical trials have shown that this prescription can improve the quality of life of HFNEF. This prompted us to use more objective indicators to further evaluate whether Yangyin Shuxin Decoction can improve the exercise capacity in HENEF patients. Methods This is a single-center parallel randomized controlled trial. The 64 patients who met the inclusion criteria were from the Cardiovascular Clinic. They will be randomly assigned to the treatment group (Yangying Shuxin Decoction combined with standard treatment) or the control group (standard treatment) according to the ratio of 1:1. The course of treatment will be 2 weeks. Both groups were interviewed at the following time points: of at enrollment (V1), and week 2 (V2), week 4 (V3), week 8 (V4), and week 12 (V5) after enrollment. The primary indicator is the peak oxygen consumption(Peak VO2) of the cardiopulmonary exercise test (CPET). Secondary indicators include CPET indicators such as anaerobic threshold oxygen consumption, carbon dioxide ventilation equivalent slope, echocardiographic indicators such as the ratio of mitral peak velocity of early filling to early diastolic mitral annular velocity(E/e′), left atrial volume index (LAVI), left ventricular mass index (LVMI), the peak velocity of tricuspid regurgitation (TR), B-type natriuretic peptide (BNP), New York Heart Association (NYHA) cardiac function grading, and so on. These indicators will be used to evaluate the effect of Yangyin Shuxin Decoction on exercise capacity in patients with HFNEF. Discussion At present, it is unclear whether the exercise capacity can be maintained after long-term use of Yangyin Shuxin Decoction. In this study, we will evaluate whether Yangyin Shuxin Decoction can improve the exercise capacity and quality of life of patients with HFNEF. This will provide an objective basis for the therapeutic effect of traditional Chinese medicine on HFNEF.