Epidemiology and outcome of new-onset atrial fibrillation in the medical intensive care unit.

OBJECTIVE: To assess the incidence of new-onset atrial fibrillation (NOAF) in the medical intensive care unit setting and describe associated characteristics and implications for long-term outcomes.

MATERIALS AND METHODS: A single-center, retrospective study of patients admitted to a medical intensive care unit from January 1, 2008, to December 31, 2013, was conducted. Atrial fibrillation (AF) diagnosis was categorized as NOAF or preexisting (PEAF). Intensive care unit characteristics along with in-hospital and long-term outcomes were compared.

RESULTS: A total of 10, 836 patients were included, 582 (5%) with NOAF, 2368 (22%) with PEAF, and 7886 (73%) with non-AF. Adjusted ICU management differed (P< .001) between all groups (NOAF vs PEAF vs non-AF) in regard to incidence of vasopressor use, mechanical ventilation, and renal replacement therapy, occurring more frequently in NOAF. Although ICU mortality was greater for NOAF (odds ratio, 1.40; 95% confidence interval, 1.03-1.87; P= .03), NOAF was not predictive of in-hospital mortality after adjustment for greater disease severity. One-year survival after ICU discharge was similar for both AF groups when compared with non-AF (54%, 52%, 75%; P< .001, log-rank).

CONCLUSIONS: Risk factors for AF were less common in NOAF than in PEAF, yet NOAF incidence was associated with greater ICU disease severity and poorer short-term ICU outcomes. New-onset AF was not independently predictive of in-hospital mortality.