Does obstructive sleep apnoea modulate cardiac autonomic function in paroxysmal atrial fibrillation?

Area of Science:

• Cardiology
• Sleep Medicine
• Autonomic Neuroscience

Background:

• The autonomic nervous system plays a crucial role in regulating cardiac function and may mediate conditions like atrial fibrillation (AF).
• Obstructive sleep apnoea (OSA) is increasingly recognized as a potential contributor to cardiovascular diseases, including AF.
• Understanding the interplay between OSA and cardiac autonomic function in patients with paroxysmal atrial fibrillation (PAF) is essential for risk stratification and management.

Purpose of the Study:

• To compare cardiac autonomic function, assessed via heart rate variability (HRV), in patients diagnosed with paroxysmal atrial fibrillation (PAF) with and without obstructive sleep apnoea (OSA).
• To investigate potential differences in autonomic modulation between these groups during different sleep stages (REM vs. Non-REM).

Main Methods:

• A case-control study involving 101 patients with PAF recruited from two tertiary centers.
• All participants underwent in-laboratory polysomnography to diagnose OSA.
• Cardiac autonomic function was evaluated using heart rate variability (HRV) analysis of ECG signals during steady-state sinus rhythm, stratified by sleep stage (REM vs. Non-REM) and OSA status.

Main Results:

• No significant differences in global HRV measures were observed between PAF patients with and without OSA during either REM or Non-REM sleep.
• Frequency-domain analysis during Non-REM sleep revealed significantly increased cardiac parasympathetic modulation (higher HF-nu) and reduced cardiac sympathetic modulation (lower LF-nu and LF/HF ratio) in PAF patients with OSA compared to those without.
• These findings remained statistically significant after adjusting for age, sex, and BMI, with no differences noted during REM sleep.

Conclusions:

• This study provides novel insights into heart rate variability in PAF patients with and without OSA, indicating limited overall HRV differences between the groups.
• However, the results suggest a chronic state of increased parasympathetic and relatively reduced sympathetic nervous system modulation in PAF patients with OSA during Non-REM sleep.
• Further research is warranted to elucidate the long-term implications of these autonomic alterations in the context of OSA and atrial fibrillation.