Prognostic impact of sustained new-onset atrial fibrillation in critically ill patients

Purpose: The development of new-onset atrial fibrillation (AF) in critically ill patients may be associated with poor outcomes. However, it is unknown whether sustained new-onset AF contributes to worse outcome. The aim of this study was to assess whether sustained new-onset AF is associated with stroke and death and to look for a possible dose–response relationship between AF duration and death. Methods: In a prospective cohort study conducted in 32 intensive care units in Japan from 2017 to 2018, we enrolled adult patients with new-onset AF. We compared patients with AF duration longer than 48 h with those with AF duration shorter than 48 h. To assess a dose–response relationship between AF duration and hospital mortality, we conducted landmark analysis and time-dependent Cox regression analysis. Results: Among a total of 423 new-onset AF patients, hospital mortality was 25%, and the incidence of in-hospital stroke was 4.6%. AF duration longer than 48 h was not independently associated with hospital mortality (adjusted odds ratio: 1.52; 95% Confidence Interval: 0.87–2.64). The incidence of in-hospital stroke was 7.6% in patients with AF duration longer than 48 h and 3.8% in those with AF duration shorter than 48 h (p = 0.154). When analyzing time more continuously, we observed a time-dependent association between AF duration and hospital mortality (p = 0.005 by landmark analysis and p = 0.019 by Cox analysis). Conclusions: Sustained new-onset AF was time-dependently associated with hospital mortality in ICU patients, albeit with some uncertainty since AF duration longer than 48 h was not independently associated with in-hospital death or stroke.