Device-Detected Atrial Fibrillation Before and After Hospitalisation for Noncardiac Surgery or Medical Illness: Insights From ASSERT

Background Atrial fibrillation (AF) is often detected during hospitalisation for surgery or medical illness and is often assumed to be due to the acute condition. Methods The Asymptomatic Atrial Fibrillation and Stroke Evaluation in Pacemaker Patients and the Atrial Fibrillation Reduction Atrial Pacing Trial (ASSERT) study enrolled patients ≥ 65 years old without AF. Pacemakers or implantable cardioverter-defibrillators recorded device-detected AF. We identified participants who were hospitalised and compared the prevalence of AF before and after hospitalisation. Results Among 2580 participants, 436 (16.9%) had a surgical or medical hospitalisation. In the 30 days following a first hospitalisation, 43 participants (9.9%, 95% confidence interval [CI] 7.2%-13.1%) had > 6 minutes of device-detected AF; 20 (4.6%, 95% CI 2.8%-7.0%) had > 6 hours. More participants had AF > 6 minutes in the 30 days following hospitalisation compared with the period 30-60 days before hospitalisation (9.9% vs 4.4%; P 6 hours (4.6% vs 2.3%, P = 0.03). Roughly half of participants with device-detected AF in the 30 days following hospitalisation had at least 1 episode of the same duration in the 6 months before (50% [95% CI 31.3%-68.7%] for > 6 min; 68.8% [95% CI 41.3%-89.0%] for > 6 h). Those with AF in the 30 days following hospitalisation were more likely to have had AF in the past (adjusted odds ratio [OR] 7.2, 95% CI 3.2-15.8 for > 6 min; adjusted OR 32.6, 95% CI 10.3-103.4 for > 6 h). Conclusions The prevalence of device-detected AF increases around the time of hospitalisation for noncardiac surgery or medical illness. About half of patients with AF around the time of hospitalisation previously had similar episodes.