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Heart rate variability in obstructive sleep apnea: a prospective study and frequency domain analysis
Lorne J Gula1, Andrew D Krahn, Allan Skanes
1Divisions of Cardiology and Respirology University of Western Ontario London, Ont, Canada.
Summary
Heart rate variability analysis in obstructive sleep apnea (OSA) reveals increased sympathetic activity in moderate OSA. Continuous positive airway pressure (CPAP) may help restore autonomic balance in severe OSA patients.
Area of Science:
- Cardiology
- Sleep Medicine
- Autonomic Neuroscience
Background:
- Obstructive sleep apnea (OSA) is associated with cyclic heart rate variations during apneic events.
- Autonomic nervous system dysfunction is suspected to influence heart rate variability (HRV) in OSA patients.
Purpose of the Study:
- To investigate the impact of OSA severity on frequency-domain measures of HRV.
- To assess changes in sympathovagal balance using the low-frequency to high-frequency (LF:HF) power ratio.
Main Methods:
- Polysomnography and Holter monitoring were used in patients with varying OSA severity and those on CPAP.
- Spectral analysis calculated LF and HF power in 5-minute intervals.
- Comparisons were made between severe OSA, moderate OSA, normal, and CPAP groups.
Main Results:
- No significant differences in overall LF or HF power were found between groups.
- The LF:HF ratio was elevated in moderate OSA compared to normal and severe OSA groups.
- The standard deviation of the LF:HF ratio was higher in moderate OSA and in CPAP users compared to normal and severe OSA.
Conclusions:
- Moderate OSA exhibits increased sympathetic tone and sympathovagal discordance, which is less pronounced in severe OSA.
- Continuous positive airway pressure (CPAP) may normalize autonomic dysregulation, shifting severe OSA towards moderate OSA characteristics.