Incidence and burden of atrial fibrillation in cryptogenic stroke patients implanted with a cardiac monitor

Abstract Introduction Implantable cardiac monitors (ICM) are increasingly being utilized for atrial fibrillation (AF) screening after ischemic stroke, but its yield depends on patient selection and prior testing. Methods This prospective registry study included consecutive patients with a cryptogenic ischemic stroke and at least one of the following predictors of incident AF: age >65 years, NT-proBNP >400 pg/mL, left atrial diameter >44 mm, frequent atrial ectopy, or involvement of multiple cerebrovascular territories compatible with an embolic source. Prior to ICM implantation, all patients underwent in-hospital telemetry monitoring (within the first 24–72 hours post-stroke) and a 7-day Holter ECG at discharge. Patients diagnosed with AF during these tests were excluded. The primary endpoint of the study was any AF episode lasting >2 minutes detected by remote monitoring of the ICM. Results Of the 308 patients who received an ICM since January 2020, 212 (69%) were male, with a mean age at implantation of 64±12 years (Table). After a median follow-up of 17.8±13.7 months, AF was detected in 66 patients (21%) overall. Twelve months after implantation, AF was diagnosed in 19% of patients (Figure). Longest AF episodes recorded by the ICM until the end of follow-up exceeded 2 minutes in 65 patients (21.1%), 6 minutes in 59 (19.2%), one hour in 49 (15.9%), 6 hours in 27 (8.8%) and 24 hours in 8 (2.6%). In one patient, we could not retrieve any information on AF episode duration. Among patients with AF diagnosis, oral anticoagulation therapy was started in 60 patients and two patients had left atrial appendage occlusion. Oral anticoagulation was recommended in the remaining four patients. Device-related complications included vasovagal reaction during the implantation procedure in one patient and premature explantation due to infection or discomfort in seven patients. Conclusions Using sequential prior testing and a pragmatic selection approach of patients with cryptogenic ischemic stroke, AF was detected by an ICM in 19% of patients after 12 months. However, only a minority of patients had AF episodes lasting longer than 24 hours.