0117 Differences In Ventricular Repolarization Between NREM And REM Sleep

Introduction Ventricular repolarization is a critical time during the cardiac cycle given its role in the pathophysiology of malignant arrhythmias. The QT Variability Index (QTVi), a measure of repolarization lability, has been associated with increased risk of ventricular arrhythmias including sudden cardiac death. Given that autonomic tone can vary during sleep, the aim of this study was to characterize NREM-REM differences in QTVi. To describe the ultradian variation, QTVi during NREM-REM sleep was examined in healthy adults. Methods A cohort of healthy men and women was identified from the Sleep Heart Health Study. Prevalent medical comorbidity such as hypertension, cardiovascular disease, and stroke were exclusionary. The ECG signal was extracted from the full montage home sleep recording and analyzed in Matlab to characterize QTVi in 30-second epochs. Given the skewed distribution of QTV, a log transformation was used. Mixed model regression was used to compare QTVi during wakefulness, NREM, and REM sleep with adjustments for age, sex and BMI. Results The sample included 87 healthy participants. The mean BMI and age was 26.6 kg/m2 and 56.2 years, respectively. The fully adjusted QTVi values for men and women during wakefulness were -1.62 and -1.39, respectively (p