Characterization of Changes in HRV Metrics During Sleep Apnea Episodes in Pediatric Patients

Previous studies, through heart rate variability (HRV) analysis, revealed an increased sympathetic dominance during sleep in patients suffering from obstructive sleep apnea (OSA). However, a separate analysis comparing episodes of apnea and normal breathing during sleep has not been performed, to characterize whether the increased sympathetic dominance is just due to the instantaneous autonomic response to each apnea or there is a sustained sympathetic activation. The HRV metrics evaluated are the temporal and frequency HRV indices, along with new spectral bands, recently identified as specific for pediatric patients diagnosed with OSA. Nonparametric paired statistical test exhibits clear significant differences in HRV, comparing for each patient values in apnea events and normal breathing during sleep and such findings are applicable for all HRV metrics except RMSSD and HF band power, whose significance during apnea events is questionable. While all previous studies analyzed HRV either for the overnight recordings or after removing the apnea events, results obtained in this work highlight the need to perform the analysis separately, both in apnea events and in normal breathing.