Atrial fibrillation (AF) is one of the most common clinical arrhythmias. Catheter ablation is an effective therapeutic strategy; however, recurrence rates remain substantial, ranging from 20% to 45%. Previous studies have established a strong association between obstructive sleep apnea (OSA) and the risk of AF recurrence following ablation. While continuous positive airway pressure (CPAP) is the standard intervention for OSA, and some observational studies suggest it may reduce post-ablation recurrence in patients with comorbid OSA, small randomized controlled trials have failed to confirm a clear benefit, potentially due to poor adherence.

This study aims to evaluate the clinical benefit of post-ablation CPAP therapy in AF patients with comorbid OSA.

Participants will:

• Be randomly assigned to either the CPAP group or the usual care group.
• If in the CPAP group, use a CPAP device for 12 months.
• Wear an ambulatory ECG recorder for a 7-day period at 3, 6, 9, and 12 months post-operation.
• Complete follow-up checkups either at the clinic or over the phone at 1, 3, 6, and 12 months after their procedure.

Atrial fibrillation (AF) is a common sustained cardiac arrhythmia, with recurrence rates of 20-45% after catheter ablation. Obstructive sleep apnea (OSA) is a common comorbidity and an important modifiable risk factor for post-ablation AF recurrence. Continuous positive airway pressure (CPAP) is the standard therapy for OSA, but its effect on reducing AF recurrence after ablation remains uncertain.This study evaluates whether CPAP therapy, compared with usual care, reduces atrial arrhythmia recurrence within 12 months after first-time catheter ablation in patients with AF and comorbid OSA.

This prospective, multicenter, open-label, parallel-group randomized controlled trial will be conducted at approximately 20 centers in mainland China. Approximately 658 adults aged 18-75 years with persistent AF and diagnosed OSA who have successfully undergone first-time catheter ablation will be enrolled.

After confirmation of eligibility and informed consent, participants will be randomized in a 1:1 ratio to receive either CPAP therapy plus usual care or usual care alone. CPAP therapy will be provided for 12 months, with treatment parameters determined by pressure titration, and adherence monitored using device-recorded data. Participants in the usual care group will receive standard AF management and standardized education regarding OSA; additional OSA treatments outside the study protocol will be permitted and documented.All participants will receive guideline-directed medical therapy for AF.

Follow-up will last at least 12 months, with assessments at approximately 1, 3, 6, and 12 months after randomization. Atrial arrhythmia monitoring will be performed primarily using ambulatory ECG recorders.

The primary outcome is freedom from atrial arrhythmia recurrence within 12 months after catheter ablation. Secondary outcomes include atrial arrhythmia recurrence patterns, arrhythmia-related interventions, atrial fibrillation burden, and changes in quality-of-life and psychological assessment scores.

Inclusion Criteria:

Patients must meet all of the following conditions to be eligible for the study:

• Age 18-75 years.
• Patients with persistent AF scheduled for first-time catheter ablation.
• Diagnosed with OSA.
• Able to tolerate CPAP therapy.
• Capable of understanding and complying with the study protocol.
• Willing to sign the informed consent form.

Exclusion Criteria:

Patients meeting any of the following criteria will be excluded from the study:

• Secondary AF.
• Left atrial anteroposterior diameter 60mm (measured via parasternal long-axis view).
• Left ventricular ejection fraction < 30%.
• Comorbid moderate-to-severe mitral stenosis or history of prosthetic valve replacement (mechanical or bioprosthetic).
• Pregnant or breastfeeding women.
• History of myocardial infarction, percutaneous coronary intervention, or cardiac surgery within 3 months prior to screening.
• History of stroke or transient ischemic attack within 6 months prior to screening.
• Perioperative complications related to the ablation procedure occurring prior to randomization.
• Inability to discontinue antiarrhythmic drugs (AADs) post-procedure due to other reasons.
• Life expectancy < 1 year.
• Central sleep apnea.
• Conditions requiring ventilatory support, including obesity hypoventilation syndrome (defined as BMI > 30kg/m² and awake PaCO₂ > 45mmHg), amyotrophic lateral sclerosis, or chronic obstructive pulmonary disease with > 1 episode of respiratory failure or hypercapnia.
• Treatment-emergent central sleep apnea during CPAP tolerance assessment that cannot be corrected prior to randomization.
• Receipt of instrumental or surgical treatment for OSA within 3 months prior to screening, including CPAP, oral appliances, ENT surgery, or bariatric surgery.
• Use of glucagon-like peptide-1 receptor agonists, glucose-dependent insulinotropic peptide receptor agonists, or glucagon receptor agonists for weight loss within 3 months prior to screening, or plans to initiate such medications within the next year.
• Current participation in other drug or device trials.