A Prospective, Single-center, Randomized Controlled Clinical Study Evaluating the Efficacy and Safety of Hyperbaric Oxygen Therapy as an Adjunctive Treatment for Chronic Heart Failure

Prior treatment

• Absolute Contraindications
  • Untreated pneumothorax or pneumomediastinum.
  • Claustrophobia, agitation or inability to cooperate, or conditions unsuitable for HBOT such as angle-closure glaucoma or eustachian tube occlusion.
  • Unstable vital signs.
  • Concurrent intracranial hemorrhage, intracranial mass, malignant tumor, uncontrolled epilepsy, psychiatric disorder, coagulation dysfunction, or other severe uncontrolled comorbidities.
  • Severe pulmonary bullae or emphysema.
  • Active internal bleeding or coagulopathy.
  • Uncontrolled hyperpyrexia (body temperature \>38.0°C).
  • Concurrent use of disulfiram, bleomycin, or cisplatin chemotherapy. Relative Contraindications
  • Uncontrolled hypertension (systolic BP \>160 mmHg or diastolic BP \>100 mmHg).
  • Severe cardiac arrhythmias (e.g., third-degree atrioventricular block without a pacemaker, frequent ventricular tachycardia).
  • Chronic obstructive pulmonary disease (FEV1 \<50% of predicted) or active asthma.
  • Psychiatric or cognitive impairment preventing cooperation with the therapy. Comorbidity Restrictions
  • End-stage renal disease (dialysis-dependent).
  • Terminal malignancy (life expectancy \<6 months).
  • Pregnancy or lactation (a negative pregnancy test is required for women of childbearing potential).
  • Recent Clinical Events
  • Acute myocardial infarction or unstable angina within the past 4 weeks.
  • Hospitalization or emergency department visit for acute heart failure within the past 2 weeks.
  • Current use of intravenous positive inotropic agents.
  • Within 6 months after cardiac surgery.
  • Use of any mechanical circulatory support.
  • Participants with a 6-minute walk test result exceeding 450 meters or who are unable to complete the test.
  • Other Exclusion Conditions
  • Inability to complete follow-up (e.g., planned relocation, non-compliance with follow-up assessments).
  • Concurrent participation in any other clinical trial that may interfere with the outcomes of this study.
  • Unforeseen circumstances judged by the investigators to be ineligible.

• Diagnostic Criteria
  • Diagnosis of chronic heart failure according to the Chinese Guidelines for the Diagnosis and Management of Heart Failure (2024), and meeting the following conditions:
  • 1.1 Left Ventricular Ejection Fraction (LVEF) ≤ 40% (HFrEF group). 1.2 Presence of chronic HF symptoms (NYHA functional class II-IV) or objective evidence (e.g., elevated natriuretic peptides, structural cardiac abnormalities).
  • 1.3 Disease duration ≥ 3 months, with no adjustments to the foundational anti-heart failure regimen within the past month.
• Age and Informed Consent 2.1 Aged 18 to 70 years (inclusive). 2.2 Understand the study purpose and provide signed informed consent.
• Treatment Stability 3.1 Received guideline-recommended, standardized "New Four Pillars" anti-heart failure therapy (ARNI/ACEI/ARB + β-blocker + MRA + SGLT2 inhibitor) for at least 2 weeks prior to enrollment, with no changes in the past month.
  • 3.2 No diuretic dose adjustments within the past 5 days and no clinical signs of fluid overload (e.g., weight gain of ≥ 2 kg/week, new-onset pulmonary edema).
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