Continuous positive airway pressure reduces nocturnal arrhythmia avalanche burden in obstructive sleep apnea: An adherence-dependent effect.

BACKGROUND

Continuous positive airway pressure (CPAP) is the primary treatment for obstructive sleep apnea (OSA), but randomized evidence for arrhythmia reduction is lacking. Nocturnal arrhythmia avalanches (NAAs)-frequent, nonsustained arrhythmic episodes associated with cardiovascular mortality-may provide enhanced statistical power for detecting treatment effects.

OBJECTIVE

This study aimed to determine whether CPAP therapy reduces NAA burden in patients with OSA and whether this effect is dependent on treatment adherence.

METHODS

We conducted a secondary analysis of electrocardiographic data from the Heart Biomarker Evaluation in Apnea Treatment randomized trial. Participants with OSA (apnea-hypopnea index 15-50 events/h) were randomized to sleep hygiene education (control), CPAP plus education, or nocturnal supplemental oxygen plus education. NAAs were defined as ≥30% drops in R-R intervals followed by a return to 90% of baseline. The primary end point was the change in NAA burden; secondary end points included adherence effects and risk factor interactions.

RESULTS

Among 245 participants with complete electrocardiographic data, baseline NAA characteristics were well balanced across groups (all P > .49). CPAP reduced NAA burden by 260 episodes (40% reduction; 95% confidence interval -510.5 to -9.5; P = .024), whereas control and nocturnal supplemental oxygen groups showed no significant change. Each additional day of effective CPAP use (≥4 h/night) was associated with 88.8 fewer NAAs (95% confidence interval -149.2 to -28.5; P = .004), a 14% reduction/adherent-night. Both high body mass index (P = .009) and smoking (P = .015) reduced CPAP therapy effectiveness.

CONCLUSION

CPAP therapy produces an adherence-dependent reduction in nocturnal arrhythmic burden in patients with OSA. This represents CPAP's positive effects on nocturnal nonsustained arrhythmic episodes, with efficacy modulated by body mass index and smoking status.