This study aims to investigate whether adjunctive hyperbaric oxygen therapy, compared to guideline-directed medical therapy with the "New Four Pillars" (ARNI/ACEI/ARB + β-blocker + MRA + SGLT2 inhibitor) alone, improves cardiac function in patients with chronic heart failure, and to evaluate its efficacy and safety.
1. Study Design This is a prospective, single-center, randomized controlled clinical trial designed to evaluate the efficacy and safety of hyperbaric oxygen therapy as an adjunctive treatment for chronic heart failure. 2. Randomization After confirming eligibility, participants will be randomized in a 1:1 ratio via a web-based randomization system into either the experimental group (hyperbaric oxygen therapy plus standard medication) or the control group (standard medication alone). 3. Treatment Protocol Patients diagnosed with chronic heart failure at the center, who meet the criteria and have no absolute contraindications for hyperbaric oxygen therapy, will be enrolled. Specifically, the study will enroll patients with Heart Failure with Reduced Ejection Fraction (HFrEF, EF ≤40%) as per the latest guidelines. Experimental Group: Participants will receive hyperbaric oxygen therapy in addition to stable, guideline-directed medical therapy based on the "New Four Pillars" (ARNI/ACEI/ARB + Beta-blocker + MRA + SGLT2 inhibitor). Control Group: Participants will receive only the standard guideline-directed medical therapy ("New Four Pillars" as above) for chronic heart failure. All other aspects of care are identical to the experimental group, except for the hyperbaric oxygen therapy. Given that chronic heart failure requires long-term management, the hyperbaric oxygen protocol is divided into three courses to consolidate and maintain efficacy, as well as to improve patients' oxygen reserve capacity and tolerance. Each course consists of 10 sessions, with a one-month interval between courses. The hyperbaric oxygen treatment will be administered in a multi-place chamber at a pressure of 0.2 MPa (2 ATA). The session protocol is as follows: 20 minutes of compression, followed by two 30-minute periods of oxygen inhalation via mask, separated by a 10-minute air break, and finally 20 minutes of decompression. The total duration per session is 110 minutes. Sessions are conducted 5 times per week, making the total duration of each treatment course 14 days. 4. Follow-up After randomization and initiation of treatment, clinical follow-up visits will be conducted to collect data. For the experimental group, follow-ups will occur one day after the completion of each hyperbaric oxygen course. All participants (both groups) will undergo additional follow-ups at 3 months, 6 months, and 12 months after the complete hyperbaric oxygen treatment regimen.
The therapy is administered in a multi-place chamber at a pressure of 0.2 MPa (2 ATA). The treatment protocol per session is as follows: 20 minutes of compression, followed by two 30-minute periods of oxygen inhalation via mask, separated by a 10-minute air break, and finally 20 minutes of decompression. The total duration per session is 110 minutes.
Fujian Medical University Union Hospital
Fuzhou, Fujian, China
6-Minute Walk Test
The 6MWT is conducted on a 30-meter, flat corridor. Patients walk back and forth as far as possible in 6 minutes. They self-pace and can stop if needed. Standardized encouragement is given. Before and after, vital signs, dyspnea, and fatigue (Borg scale) are recorded. The primary outcome is the total distance walked (6MWD).
Time frame: 6MWT will be performed in the experimental group at baseline (pre-HBOT), one day after each HBOT course, and at 3, 6, and 12 months post-treatment.
Cardiac Color Doppler Ultrasound
During the test, the patient lies on their left side. A technician places a transducer with gel on the chest to obtain ultrasound images of the heart. It captures real-time images of chamber size, muscle thickness, valve motion, and pumping function (ejection fraction). The procedure is painless, takes about 30-45 minutes, and requires no special preparation.
Time frame: Echocardiograms will be performed at baseline, following each HBOT course (1-day), and at 3, 6, and 12-month follow-ups.
Cardiopulmonary Exercise Testing (CPET)
Cardiopulmonary Exercise Testing (CPET) measures how the heart, lungs, and muscles work during exercise. The patient exercises on a treadmill or stationary bike with increasing intensity while wearing a mask to analyze oxygen and carbon dioxide. Vital signs are monitored throughout. The test lasts 10-15 minutes and evaluates overall cardiopulmonary fitness.
Time frame: CPET will be performed at baseline, 1-day post-each HBOT course, and at 3/6/12-month follow-ups.
Non-Invasive Cardiac Output Monitoring
Non-Invasive Cardiac Output Monitoring (NICOM) measures heart function without inserting catheters. Electrode sensors are placed on the patient's chest to track blood flow dynamics using bioimpedance or bioreactance technology. The patient remains still during the 10-20 minute test, which provides real-time data on cardiac output and stroke volume. No special preparation is required.
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Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
150
Time frame: Non-Invasive Cardiac Output Monitoring (NICOM) results will be recorded at baseline, one day after each hyperbaric oxygen treatment course, and at 3, 6, and 12 months post-treatment.
Kansas City Cardiomyopathy Questionnaire
The KCCQ is a self-administered questionnaire. Patients answer 23 items about their heart failure symptoms and how it impacts their life over the past 2 weeks. It takes about 5-10 minutes to complete and produces scores from 0-100, where higher scores indicate better health status and quality of life.
Time frame: KCCQ will be administered at baseline, 1-day post-each HBOT course, and during 3/6/12-month follow-ups.
Meta-Analysis Global Group in Chronic Heart Failure
The MAGGIC questionnaire is a 13-item prognostic risk score for heart failure patients. It combines patient data (age, gender, BMI, smoking status) with clinical metrics (ejection fraction, systolic BP, creatinine, NYHA class, medication use) and disease history (diabetes, COPD, heart failure duration). Clinicians collect these parameters to calculate a risk score predicting 1- and 3-year mortality. Completion time is 5 minutes.
Time frame: The MAGGIC risk score will be calculated at baseline, one day after each hyperbaric oxygen treatment course, and at 3, 6, and 12 months post-treatment.
Pittsburgh Sleep Quality Index (PSQI)
The PSQI is a self-rated questionnaire assessing sleep quality over a 1-month interval. It contains 19 items generating seven component scores: subjective quality, latency, duration, efficiency, disturbances, medication use, and daytime dysfunction. These components yield a global score (0-21), with higher scores indicating worse sleep quality. Administration requires 5-10 minutes.
Time frame: PSQI will be administered at baseline, 1-day post-each HBOT course, and during 3/6/12-month follow-ups.