Associations of the Low Arousal Threshold With Arrhythmia Burden and Heart Rate Variability in Obstructive Sleep Apnea Using Polysomnography With 24‐h Holter Electrocardiography

Obstructive sleep apnea (OSA) is a widespread condition that increases the risk of arrhythmias. Recently, the role of specific OSA phenotypes, including the low respiratory arousal threshold (ArTH) phenotype, has been largely explored. This study aimed to assess whether the estimated low ArTH in patients with obstructive sleep apnea is significantly associated with arrhythmia burden and alterations in heart rate variability (HRV). Data from adults who underwent full-night video-polysomnography (vPSG) with 24-h 12-lead Holter electrocardiography (ECG) were included. ArTH was estimated noninvasively using the Edwards method. Arrhythmias were scored and counted. HRV was quantified in time, geometric, and frequency domains using ECG across a predefined circadian schedule. The analysis included 166 participants; 134 were classified as low ArTH, and 32 as high ArTH. The low ArTH group had a lower supraventricular arrhythmia burden, including fewer supraventricular premature contractions (SVPC), fewer SVPC pairs, and fewer supraventricular tachycardia (SVT) episodes than the high ArTH group. Daytime HRV differed between the groups, with higher RMSSD in low ArTH and higher LF power. In multivariable analyses, low ArTH remained associated with SVPC and SVPC pairs. Differences in HRV parameters were limited and were largely attenuated after adjustment for clinical confounders. The results suggest the potential importance of the ArTH phenotype as an independent indicator of arrhythmia in patients with OSA. However, the results should be interpreted as exploratory and hypothesis gathering. Further, prospective studies are needed to assess the utility of ArTH in risk stratification.