Obstructive sleep apnea as a predictor of reduced heart rate variability.

PURPOSE: This study aimed to analyze the relationship between the occurrence of obstructive sleep apnea (OSA) and heart rate variability (HRV) in a group of patients with clinical suggestion of OSA.

METHODS: 104 patients with clinical suspicion of OSA were qualified to participate in the study (age: 53.15 ± 13.43 years). All participants took part in a survey and were subjected to laboratory tests, 24-hour ECG Holter monitoring, and polysomnography. The participants were divided into groups depending on the criterion of the presence of OSA.

RESULTS: The analysis of time HRV demonstrated lower parameters of SDNN for the entire recording and a 15-minute fragment of daily activity, as well as a lower pNN50 for the entire recording in those patients with diagnosed OSA. A statistically significant difference was observed for the spectral analysis of the LF/HF which was higher in the participants with OSA during the 15-minute fragment of N3 sleep. A negative correlation was observed between AHI and the following parameters: SDSD from the entire Holter recording (r = -0.21, p < 0.05) and from the 15-minute fragment of daily activity (r = -0.19, p < 0.05), mRR from the fragment of N3 sleep (r = -0.19, p < 0.05) and VLF from the entire Holter recording (r = -0.26, p < 0.05). A statistically significant positive correlation between AHI and LF/HF in 15-minute fragments of N3 sleep was found (r = 0.26, p < 0.05).

CONCLUSIONS: The study group of patients with OSA is characterized by reduced HRV. The higher AHI constitutes an independent predictor of reduced HRV, both in the sympathetic and parasympathetic components, and the sympathetic-parasympathetic balance.