Sleep-related hypoxemia was found to be a better predictor of atrial fibrillation (AF) risk was compared to the traditionally used apnea-hypopnea index (AHI).

The study showed that among 42,057 people without AF at baseline, 1947 developed AF over the following five years. In a multivariate model, incident AF rose by 6% for each 10-unit boom in percentage sleep time with oxygen saturation much less than 90% (T90) (chance ratio [HR], 1.06; 95%  CI, 1.04-1.08). Also, in comparison to people with T90 of much less than 0.1 %, patients with the highest T90 (11.6%) had 28% higher risk of developing AF compared to reference patients with T90 of less than 0.1% (HR, 1.28; 95% CI, 1.11-1.47).

The prevalence of AF accelerated by 9% (HR, 1.09; 95% CI, 1.03-1.15) for each 10-unit decrease in minimal oxygen saturation (SaO2) and by 30% (HR, 1.3; 95% CI, 1.18-1.42), for each 10-unit decrease in mean SaO2, while a 2% increase in the threat of developing AF (HR, 1.02; 95% CI, 1.00-1.03) was seen for each 10-unit increase in AHI.

The data imply that sleep-related hypoxia is a "significant factor" in the onset of AF. The mechanisms underlying hypoxemia and atrial fibrillation are linked to autonomic dysfunction, or surges of sympathetic activity and oxidative stress on tissues at the cellular level, which result in changes in the cardiac substrate, such as fibrosis, which then lead to arrhythmia, particularly atrial fibrillation. The findings were presented at SLEEP 2022, the 36th annual meeting of the Associated Professional Sleep Societies. (Medscape - Jun 07, 2022.)