Researchers have identified a link between sleep apnea, a sleep disorder, and the development of atrial fibrillation -- a common heart rhythm disorder.

Published in the Journal of the American Heart Association, the study of over 42,000 patients found that sleep-related hypoxia -- or low oxygen levels during sleep -- is associated with a higher risk of developing atrial fibrillation over time. 

The study by researchers from Cleveland Clinic found that the risk persisted even after accounting for lung function, suggesting sleep-related hypoxia independently increases atrial fibrillation risk separate from any underlying lung disease.

Atrial fibrillation (AFib) is an irregular and often very rapid heart rhythm (arrhythmia) that can lead to blood clots in the heart. The abnormally fast heart rate can lead to poor blood flow and increases the risk of stroke, heart failure and other heart-related complications.

The study showed that 5 per cent of patients were diagnosed with AFib within five years of their sleep study despite the cohort being fairly young (mean of 51 years old). It also found that for every 10 percentage point decrease in mean oxygen saturation, the risk of AFib increased by 30 per cent.

Regular screening for and treating sleep apnea may help reduce the likelihood of developing atrial fibrillation, especially in those already at high risk, according to the researchers.

The researchers plan future studies to better understand the mechanisms linking sleep-disordered breathing, which includes sleep apnea and sleep-related hypoxia, to AFib development. 

They also aim to examine whether current treatments for sleep apnea, such as CPAP, can help lower AFib risk. Their findings can inform future clinical trials of sleep-disordered breathing treatments, such as supplemental oxygen at night, the researchers said.