New-onset atrial fibrillation in critically ill patients and its association with mortality: A report from the FROG-ICU study

Atrial fibrillation (AFib) is associated with adverse outcome in critical illness, but whether this effect is independent from other risk factors remains uncertain. New-onset AFib during critical illness may be independently associated with increased in-hospital and long-term risk of death. FROG-ICU was a prospective, observational, multi-centre cohort study designed to investigate the outcome of critically ill patients. Inclusion criteria were invasive mechanical ventilation and/or treatment with a positive inotropic agent for >24 h. Heart rhythm was assessed at inclusion and during ICU stay with digital ECG recordings. Among patients who had AFib during ICU stay, new-onset and recurrent AFib were diagnosed in patients without and with previous history of AFib, respectively. Primary endpoint was in-hospital mortality; secondary endpoint was 1-year mortality among ICU survivors. The study included 1841 critically ill patients. During ICU stay, AFib occurred in 343 patients (19%). New-onset AFib (n = 212) had higher in-hospital mortality compared to no AFib (47 vs. 23%, P