A Study to Evaluate the Safety and Efficacy of NT-88

Inclusion Criteria: 1. Aged ≥18 years, no gender restriction; 2. Willing to participate in the study, understand and sign the informed consent form (ICF); 3. Established diagnosis of heart failure with signs and/or symptoms of heart failure; Symptoms: Dyspnea, reduced exercise tolerance, fatigue, exhaustion, etc.;Signs: Scattered moist rales in limited lung fields (clinically defined as: sparse, discontinuous, fine bubbling sounds heard in 1-2 localized lung areas during mid-to-late inspiration) or accompanied by mild cardiac murmur; Diagnostic examinations (key for confirmation): Echocardiography, natriuretic peptide testing, electrocardiography. 4. Cardiac imaging examination (primarily echocardiography) demonstrating LVEF 41%-49%; 5. New York Heart Association (NYHA) functional Class II-III (see Appendix 1); 6. Clinically stable condition with no significant changes in symptoms, signs, or treatment regimen for at least 3 months; 7. Normal cognitive function. Exclusion Criteria: 1. Known allergy to any component of the investigational product; 2. Complicated with cardiogenic shock, acute severe myocarditis, poorly controlled malignantarrhythmia, hypertrophic obstructive cardiomyopathy, constrictive pericarditis, cardiac tamponade, severevalvular disease requiring surgical intervention, or pulmonary embolism, among others; 3. Hospitalization for acute heart failure decompensation within the past 3 months; 4. Implantation of implantable cardioverter-defibrillator (ICD) or cardiac resynchronization therapy(CRT) within 3 months; 5. Uncontrolled hypertension, defined as resting systolic blood pressure ≥180 mmHg and/or diastolicblood pressure ≥110 mmHg at two separate assessments prior to randomization; 6. Alanine aminotransferase (ALT) or aspartate aminotransferase (AST), or total bilirubin \>3 times theupper limit of normal (ULN) due to non-cardiac causes; estimated glomerular filtration rate (eGFR) \<15mL/min/1.73 m²; or serum potassium \>5.5 mmol/L; 7. Acute coronary syndrome, stroke, or transient ischemic attack within 3 months; cardiac, carotid, orother major vascular surgery; percutaneous coronary intervention (PCI), carotid angioplasty, coronary arterybypass grafting (CABG), or other cardiac surgery within 3 months; or recent onset of non-cardiac conditions affecting exercise capacity, or conditions that may be exacerbated by vigorous exercise (such as infection,hepatic or renal failure, thyrotoxicosis, etc.); 8. Major surgery within 6 months; 9. Serious primary diseases of the liver, kidney, hematopoietic system, nervous system, endocrinesystem, or other severe systemic diseases; malignancy; or psychiatric disorders; 10. Acute infection; 11. Positive for human immunodeficiency virus (HIV) antibody, positive syphilis test, or hepatitis B orhepatitis C infection; 12. Life expectancy \<1 year; 13. Known hypersensitivity to any study drug, or history of chronic urinary tract infection, or prior orplanned bariatric surgery; 14. Women who are pregnant, breastfeeding, or planning pregnancy; 15. Participation in another clinical study within 3 months; 16. Subjects deemed unsuitable for participation in this trial by the investigator.