| Title | Heart rate variability during wakefulness as a marker of obstructive sleep apnea severity. | ||
| Author | Qin, Hua; Keenan, Brendan T; Mazzotti, Diego R; Vaquerizo-Villar, Fernando; Kraemer, Jan F; Wessel, Niels; Tufik, Sergio; Bittencourt, Lia; Cistulli, Peter A; de Chazal, Philip; Sutherland, Kate; Singh, Bhajan; Pack, Allan I; Chen, Ning-Hung; Fietze, Ingo; Gislason, Thorarinn; Holfinger, Steven; Magalang, Ulysses J; Penzel, Thomas | ||
| Journal | Sleep | Publication Year/Month | 2021-May |
| PMID | 33506267 | PMCID | PMC8120337 |
| Affiliation + expend | 1.Interdisciplinary Center of Sleep Medicine, Charite-Universitatsmedizin Berlin, Berlin, Germany. | ||
STUDY OBJECTIVES: Patients with obstructive sleep apnea (OSA) exhibit heterogeneous heart rate variability (HRV) during wakefulness and sleep. We investigated the influence of OSA severity on HRV parameters during wakefulness in a large international clinical sample. METHODS: 1247 subjects (426 without OSA and 821 patients with OSA) were enrolled from the Sleep Apnea Global Interdisciplinary Consortium. HRV parameters were calculated during a 5-minute wakefulness period with spontaneous breathing prior to the sleep study, using time-domain, frequency-domain and nonlinear methods. Differences in HRV were evaluated among groups using analysis of covariance, controlling for relevant covariates. RESULTS: Patients with OSA showed significantly lower time-domain variations and less complexity of heartbeats compared to individuals without OSA. Those with severe OSA had remarkably reduced HRV compared to all other groups. Compared to non-OSA patients, those with severe OSA had lower HRV based on SDNN (adjusted mean: 37.4 vs. 46.2 ms; p < 0.0001), RMSSD (21.5 vs. 27.9 ms; p < 0.0001), ShanEn (1.83 vs. 2.01; p < 0.0001), and Forbword (36.7 vs. 33.0; p = 0.0001). While no differences were found in frequency-domain measures overall, among obese patients there was a shift to sympathetic dominance in severe OSA, with a higher LF/HF ratio compared to obese non-OSA patients (4.2 vs. 2.7; p = 0.009). CONCLUSIONS: Time-domain and nonlinear HRV measures during wakefulness are associated with OSA severity, with severe patients having remarkably reduced and less complex HRV. Frequency-domain measures show a shift to sympathetic dominance only in obese OSA patients. Thus, HRV during wakefulness could provide additional information about cardiovascular physiology in OSA patients. CLINICAL TRIAL INFORMATION: A Prospective Observational Cohort to Study the Genetics of Obstructive Sleep Apnea and Associated Co-Morbidities (German Clinical Trials Register - DKRS, DRKS00003966) https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00003966.