Spontaneous fluctuation in atrial fibrillation burden and duration in patients with implantable loop monitors

• Published in: Pacing and clinical electrophysiology 2024-11, Vol.47 (11), p.1454-1463
• Main Authors: Mekary, Wissam, Campbell, Martin, Bhatia, Neal K., Westerman, Stacy, Shah, Anand, Leal, Miguel, Delurgio, David, Patel, Anshul M., Tompkins, Christine, El‐Chami, Mikhael F., Merchant, Faisal M.
• Format: Article
• Language: English
• Subjects: Aged; Anticoagulants - therapeutic use; atrial fibrillation; Atrial Fibrillation - physiopathology; burden; Cardiac arrhythmia; duration; Electrocardiography, Ambulatory - instrumentation; Female; Fibrillation; Humans; implantable loop recorder; Male; Patients; Retrospective Studies; stroke; Time Factors
• ISSN: 0147-8389; 1540-8159; 1540-8159
• DOI: 10.1111/pace.15072

Background Most studies of device‐detected atrial fibrillation (AF) have recommended indefinite anticoagulation once a patient crosses a particular threshold for AF duration or burden. However, durations and burdens are known to fluctuate over time, but little is known about the magnitude of spontaneous fluctuations and the potential impact on anticoagulation decisions. Objective To quantify spontaneous fluctuations in AF duration and burden in patients with implantable loop recorders (ILRs) Methods We reviewed all ILR interrogations for patients with non‐permanent AF at our institution from 2018 to 2023. We excluded patients treated with rhythm control. The duration of longest AF episode at each interrogation was classified as  24 h, and the AF burden reported at each interrogation was classified as  11.4%. Results Out of 156 patients, the mean age at ILR implant was 70.9 ± 12.5 years, CHA2DS2‐VASc score was 4.2 ± 1.8, duration of ILR follow‐up was 23.4 ± 11.2 months, and number of ILR interrogations per patient was 18.0 ± 8.9. The duration of longest AF episode at any point during follow‐up was  24 h in 110, 30, and 16 patients, respectively. Among the 30 patients with a longest AF episode of 6–24 h at some point during follow‐up, out of 594 total ILR interrogations, only 75 (12%) showed a longest episode of 6–24 h. In the remaining 519 interrogations, the longest episode was  24 h at any point during follow‐up (n = 16), only 47 out of 320 total ILR interrogations (15%) showed an episode of > 24 h. When evaluating AF burden, 96, 38, and 22 patients had maximum reported AF burdens of  11.4% at any point during ILR follow‐up. Among those with a maximum burden of 2%–11.4% at some point during follow‐up (n = 38), out of 707 ILR interrogations, only 76 (11%) showed a burden of 2%–11.4%. In the remaining 631 interrogations, the burden was  11.4% at some point during follow‐up, only 80 out of 480 interrogations (17%) showed a burden of > 11.4%. In 65% of interrogations, the burden was  24 h at some point during follow‐up, the vast majority of interrogations show episodes of  11.4% at