Obstructive sleep apnoea syndrome and recurrent vasovagal syncope: Insights from a multicentre observational study

Resolution of recurrent syncopal episodes after the diagnosis and treatment of obstructive sleep apnoea syndrome (OSA) has been reported in a few cases, but it is unknown whether a true syncope is associated with OSA.

To evaluate the impact of diagnosing and treating OSA on the frequency of recurrent vasovagal syncope (RVS) episodes in patients with OSA and co-morbid RVS.

A multicentre interventional observational study was conducted in patients with OSA and RVS. Patients underwent continuous positive airway pressure (CPAP) therapy for at least 12 months. The frequency of RVS episodes (with and without loss of consciousness), quality of life and polysomnographic variables were assessed during the 6 months before CPAP initiation and during the last 6 months before the follow-up visits after CPAP therapy.

Twenty-seven patients (66.7% female; mean age 42.1±12.8 years; mean body mass index 25.6±3.5kg/m²; mean apnoea-hypopnoea index 22.2±12.1 events/hour) completed 12 months of CPAP therapy. The frequency of RVS episodes decreased significantly following treatment. Episodes with loss of consciousness declined from 25.7±38.6 to 17.7±40.3 (P<0.05), and episodes without loss of consciousness dropped from 39.7±78.6 to 9.3±8.5 (P<0.05). CPAP therapy was also associated with significant improvements in daytime sleepiness (Epworth Sleepiness Scale: 9.3±6.5 to 3.9±5.7; P=0.0016; 95% confidence interval 2.24 to 8.50), fatigue (Pichot Scale: 16.0±9.8 to 3.9±5.1; P=0.000001; 95% confidence interval 8.13 to 16.09) and percentage of patients with positive depression scores (35.3% to 9.1%; P=0.00025; 95% confidence interval -4.96 to-1.96). No statistically significant changes were observed in heart rate variability or 24-hour blood pressure variables.

CPAP therapy significantly reduces RVS recurrence in patients with OSA, suggesting that it is a modifiable risk factor for RVS. These findings highlight the importance of OSA screening in patients with unexplained syncope. Randomized controlled trials are required to mitigate potential results bias caused by the observational study design.