A recent study published on June 10 in the Journal of Arrhythmia suggests that the effects of sleep apnea on heart health may be more pronounced during the day than at night. According to Dr. Reena Mehra, a sleep medicine specialist at UW Medicine, these findings could enhance treatment approaches for atrial fibrillation, a condition that affects 1 in 20 adults in the U.S. and increases the risk of blood clots, stroke, and heart failure.
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Sleep apnea involves repeated breathing interruptions during sleep, leading to decreased oxygen levels, increased carbon dioxide, and elevated blood pressure, ultimately disrupting sleep quality. Chronic sleep apnea is associated with a significantly higher risk of heart problems, including a two to five times greater likelihood of developing an irregular heartbeat, particularly atrial fibrillation.
Dr. Mehra's research is part of the larger Sleep Apnea and Atrial Fibrillation Biomarkers and Electrophysiologic Atrial Triggers (SAFEBEAT) project, focusing on a group of 150 individuals diagnosed with atrial fibrillation. In their study, the team utilized electrocardiography to monitor heart rate variability, a key indicator of heart function, while assessing sleep apnea and providing treatment via continuous positive airway pressure (CPAP) machines.
Contrary to their expectations, the research revealed that heart rate variability showed greater abnormalities during wakefulness rather than during sleep. Dr. Mehra noted that this may indicate that the cumulative effects of sleep apnea may peak during the daytime or that increased physical activity during the day amplifies these effects.
These insights may prompt changes in the diagnosis and management of atrial fibrillation, suggesting that daytime monitoring could be beneficial and that medication effectiveness might improve if timed for daytime use. Following treatment with CPAP machines, patients exhibited improved sleep apnea symptoms and more normalized heart rate variability, indicating that addressing sleep apnea is crucial in the management of atrial fibrillation.
The study is exploratory, and Dr. Mehra is advancing to a randomized, controlled trial to further evaluate the impact of CPAP on atrial fibrillation. Additionally, she is investigating whether distinct biomarkers of sleep apnea and atrial fibrillation can be detected in patients’ blood. This research has received support from the National Institutes of Health National Heart, Lung and Blood Institute.