Stroke Risk in Transient Hospital-Onset Atrial Fibrillation

The clinical significance of new-onset atrial fibrillation that occurs transiently in patients hospitalized for other reasons is unclear: It can be fleeting, provoked by stress, or it can be a harbinger of further episodes and indicate elevated stroke risk. Guidelines offer no definitive recommendations; however, evidence from 2025 sheds light on this topic.

Researchers in Canada examined 20,000 older medical and surgical inpatients who developed new-onset atrial fibrillation as a secondary diagnosis. One-year stroke risk without anticoagulation was consistently low (1.0%–1.3%) and substantially lower than risk typically seen in patients admitted for atrial fibrillation. When stratified by CHA₂DS₂-VA score, patients with scores of ≤4 had par…