Risk of thromboembolism in patients developing critical illness-associated atrial fibrillation.

Although common, the long-term significance of -developing atrial fibrillation (AF) during a period of critical illness is unclear. We undertook a retrospective cohort analysis to -assess the rate of thromboembolism (TE) in patients -developing atrial fibrillation de novo during admission to our intensive care unit. In total, 1,955 patients were followed up (-maximum follow-up 1,276 days) for the occurrence of TE, of which 220 (11.3%) had developed AF or atrial flutter during their critical care admission. There were 11 TE events among the patients with new AF (0.053 events per patient-year), compared with 18 in the non-AF group (0.0059 events per patient-year). The unadjusted hazard ratio for TE in patients developing new AF compared with those not developing AF was 8.09 (95% CI 3.08-17.19, p