Cardiac Autonomic Function in Obstructive Sleep Apnoea: Implications for Cardiovascular Risk

Abstract

Purpose: This study examines the link between obstructive sleep apnoea (OSA) and cardiovascular disease. Factors such as intermittent hypoxia, sleep arousal, and intrathoracic pressure swings activate the sympathetic nervous system, causing blood pressure and heart rate surges negatively effecting cardiovascular function. This thesis aims identify OSA patients at higher cardiovascular risk and determine if treating OSA restores cardiovascular autonomic function.

Methods: Chapter 3 investigates excessive daytime sleepiness and its association with cardiovascular risk. Chapter 4 explores the rapid eye movement (REM)-related OSA and nocturnal heart rate variability (HRV) profiles. Chapter 5 examines OSA severity and cardiac autonomic function in patients with coronary artery disease. Chapter 6 evaluates the effect of OSA therapy on cardiac autonomic function. Chapter 7 assesses whether six-month OSA therapy improves cardiac autonomic function in OSA patients with heigher cardiovascular risk.

Results: Chapter 3 shows vagal withdrawal in patients with excessive daytime sleepiness. Chapter 4 finds that patients with REM-related OSA have higher cardiac vagal modulation. Chapter 5 shows no significant associations in cardiac autonomic function in the context of OSA and coronary artery disease. Chapter 6 indicates that MAS therapy for OSA increases cardiac vagal modulation. Chapter 7 demonstrates that a six-month MAS therapy intervention results in increased HRV, improving cardiac autonomic adaptability in OSA patients with higher cardiovascular risk.

Conclusion: Cardiac autonomic function markers may help identify higher cardiovascular risk, particularly those with excessive daytime sleepiness. Confounding factors, such as sex, might alter this pathway. The effect of OSA severity in patients with existing cardiovascular disease requires further investigation. OSA therapy improves cardiac autonomic adaptability in patients with higher cardiovascular risk.