Atrial Fibrillation in Critically Ill Patients: Incidence and Outcomes

BACKGROUND

Atrial fibrillation (AF), either chronic or new onset, is common in critically ill patients. Its epidemiology and relationship with clinical outcomes are poorly known.

OBJECTIVE

To understand the burden of AF in patients admitted to the ICU and its impact on patients' outcomes.

METHODS

This is a single-center, retrospective cohort study evaluating all patients with AF admitted to a non-cardiac intensive care unit over the course of 54 months. Clinical outcomes were evaluated in the short (hospital discharge) and long term (two-year follow-up). The hazard ratio (HR) with 95% CI was computed for the whole population as well as for propensity score-matched patients, with or without AF.

RESULTS

A total of 1357 patients were screened (59.1% male), with a mean age of 75 ± 15.2 years, length of intensive care unit stay of 4.7 ± 5.1 days, and hospital mortality of 26%. A diagnosis of AF was found in 215 patients (15.8%), 142 of whom had chronic AF. The hospital all-cause mortality was similar in patients with chronic or new-onset AF (31% vs. 28.8%, p = 0.779). Patients with AF had higher in-hospital, one-year, and two-year crude mortality (30.2% vs. 22.9%, p = 0.024; 47.9% vs. 35.3%, p = 0.001; 52.6% vs. 38.4%, p < 0.001). However, after propensity score matching (N = 213), this difference was no longer significant for in-hospital mortality (OR: 1.17; 95% CI: 0.77-1.79), one-year mortality (OR: 1.38; 95% CI: 0.94-2.03), or two-year mortality (OR: 1.30; 95% CI: 0.89-1.90).

CONCLUSIONS

In ICU patients, the prevalence of AF, either chronic or new-onset, was 15.8%, and these patients had higher crude mortality. However, after adjustment for age and severity on admission, no significant differences were found in the short- and long-term mortality.