Variability of Sleep Apnea Severity and Risk of Atrial Fibrillation The VARIOSA-AF Study

OBJECTIVES This study sought to determine night-to-night variability in the severity of steep-disordered breathing (SDB) and the dynamic intraindividual relationship to daily risk of incident atrial fibrillation (AF) by using simultaneous tong-term day-by-day SDB and AF monitoring. BACKGROUND Night-to-night variability in SDB severity may result in a dynamic exposure to SOB related conditions impacting the timing and extent of cardiovascular responses. METHODS This study was an observational cohort study. Daily data for AF burden and average respiratory disturbance index (RDI) were extracted from pacemakers capable of monitoring nightly SOB and daily AF burden in 72 patients. Nightly RDI values were grouped into quartiles of severity within each patient. AF burdens of >5 min, >1 h, and >12 h were the outcome variables. RESULTS A total of 32% of patients had a mean RDI of >20/h, indicative of overall severe SDB. There was significant night-to-night variation in RDI reflected by an absolute SD of +/- 6.3 events/h (range 2 to 14 events/h) within any given patient. Within each patient, the nights with the highest RDI On their highest quartile) conferred a 1.7-fold (1.2 to 2.2; p < 0.001), 2.3-fold (1.6 to 3.5; p < 0.001), and 10.2-fold (3.5 to 29.9; p < 0.001) increase risk of having at least 5 min, 1 h, and 12 h, respectively, of AF during the same day compared with the best steep nights (in their lowest quartiles). CONCLUSIONS There is considerable night-to-night variability in SDB seventy which cannot be detected by 1 single overnight steep study. SDB burden may be a better metric with which to assess the extent of dynamic SDB related cardiovascular responses such as daily AF risk than the categorical diagnosis of SDB. Crown Copyright (C) 2019 Published by Elsevier on behalf of the American College of Cardiology Foundation. All rights reserved.