TY - JOUR T1 - Obstructive sleep apnoea-related respiratory events and desaturation severity are associated with the cardiac response JF - ERJ Open Research JO - erjor DO - 10.1183/23120541.00121-2022 VL - 8 IS - 4 SP - 00121-2022 AU - Salla Hietakoste AU - Tuomas Karhu AU - Saara Sillanmäki AU - Raquel Bailón AU - Thomas Penzel AU - Juha Töyräs AU - Timo Leppänen AU - Sami Myllymaa AU - Samu Kainulainen Y1 - 2022/10/01 UR - http://openres.ersjournals.com/content/8/4/00121-2022.abstract N2 - Background Obstructive sleep apnoea (OSA) causes, among other things, intermittent blood oxygen desaturations, increasing the sympathetic tone. Yet the effect of desaturations on heart rate variability (HRV), a simple and noninvasive method for assessing sympathovagal balance, has not been comprehensively studied. We aimed to study whether desaturation severity affects the immediate HRV.Methods We retrospectively analysed the electrocardiography signals in 5-min segments (n=39 132) recorded during clinical polysomnographies of 642 patients with suspected OSA. HRV parameters were calculated for each segment. The segments were pooled into severity groups based on the desaturation severity (i.e. the integrated area under the blood oxygen saturation curve) and the respiratory event rate within the segment. Covariate-adjusted regression analyses were performed to investigate possible confounding effects.Results With increasing respiratory event rate, the normalised high-frequency band power (HFNU) decreased from 0.517 to 0.364 (p<0.01), the normalised low-frequency band power (LFNU) increased from 0.483 to 0.636 (p<0.01) and the mean RR interval decreased from 915 to 869 ms (p<0.01). Similarly, with increasing desaturation severity, the HFNU decreased from 0.499 to 0.364 (p<0.01), the LFNU increased from 0.501 to 0.636 (p<0.01) and the mean RR interval decreased from 952 to 854 ms (p<0.01). Desaturation severity-related findings were confirmed by considering the confounding factors in the regression analyses.Conclusion The short-term HRV response differs based on the desaturation severity and the respiratory event rate in patients with suspected OSA. Therefore, a more detailed analysis of HRV and desaturation characteristics could enhance OSA severity estimation.Higher short-term HRV is related to more severe oxygen desaturations and a higher rate of respiratory events. Considering HRV and desaturation characteristics in the diagnosis of OSA could be useful when assessing the cardiac consequences of OSA. https://bit.ly/3yZSYTR ER -