Understanding the Relationship Between Sleep Apnea, Atrial Fibrillation

For patients with atrial fibrillation (AF), current guidelines on diagnosis and management of AF by the European Society for Cardiology (ESC) highlight the importance of identifying and managing risk factors that may exacerbate adverse events.

In a commentary published by IJC Heart & Vasculature, authors Dominik Linz, MD, PhD, Department of Cardiology, Maastricht University Medical Center and Cardiovascular Research Institute, and Dobromir Dobrev, MD, Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, discussed the implications that management of sleep-disordered breathing (SBD), which is among the listed risk factors, can have on outcomes in patients with AF.

Notably, SDB is highly prevalent in patients with AF. In a recent study that screened for sleep apnea in patients with paroxysmal AF (n = 579), 82.7% of those assessed were found to have an apnea-hypopnea index (AHI) of 5 or greater, indicating mild sleep apnea, and 42.1% received a diagnosis of moderate to severe sleep apnea (AHI ≥ 15).

As authors highlight, patients with more severe SDB had a higher AF burden, severity, and symptom score. “This suggests that SDB could represent a modifiable determinant of symptom burden in patients with AF and should warrant consequent management.”

So, which types of SDB should be monitored and treated in patients with AF?

In looking at the current ESC guidelines, authors say that obstructive sleep apnea (OSA) should be the main focus when assessing diagnosis and management of AF. While this relationship has been established, they say that it remains to be known what the pathophysiological link is between central sleep apnea (CSA) or Cheyne Stokes respiration and AF.

“Mechanisms including apnea-induced hypoxia with intermittent arousal, fluctuating levels of carbon dioxide, enhanced sympathetic/neurohormonal activation, and oxidative stress causing inflammation have been implicated as etiologic causes of AF within this subpopulation,” expanded the researchers. “However, it remains unclear how and whether CSA represents a treatment target to control sinus rhythm.”

Speaking on how to screen for SDB in patients with AF, researchers wrote that diagnosis and treatment of sleep apnea requires a “close interdisciplinary collaboration between the electrophysiologist/cardiologist and sleep specialists, possibly within an integrated care model.”

Moreover, assessing for SDB may require several assessments, as SDB may show a high visit-to-visit or even day-to-day variability. “Importantly, this visit-to-visit or day-to-day variability does not just complicate the detection of AF risk factors, including SDB, but may also directly result in a dynamic substrate for AF by apnea associated transient arrhythmogenic effects.”

Utilizing a longitudinal and remote structured monitoring infrastructure was referenced as a potential strategy, which may be achieved through mobile health applications and technologies such as Bluetooth-linked devices.

In concluding, researchers emphasized that the lack of symptoms characteristic of excessive daytime sleepiness in patients with AF should not preclude these populations from being investigated for potentially comorbid SDB.

“Although technologies for longitudinal monitoring of lifestyle components and AF risk factors, including SDB monitoring, are available, legal considerations and missing reimbursement models are still blocking the wide implementation in existing clinical pathways,” they wrote.

Reference

Linz D, Dobrev D. Sleep apnea and atrial fibrillation: update 2020. Int J Cardiol Heart Vasc. Published online November 27, 2020. doi:10.1016/j.ijcha.2020.100681