Response to Clinical Challenges in Identifying and Managing Asymptomatic Atrial Fibrillation: Insights and Limitations

We are grateful to Kataoka and Imamura for their letter regarding our manuscript evaluating atrial fibrillation (AF) event characteristics stratified by reported symptom status. The interpretation of these findings should be in the context of the demographics of this large cohort of participants with implantable cardiac monitors (ICM) in situ. A small proportion, 785 (7%) of the 11 267 participants, had their ICM implanted for management after catheter ablation. One thousand and eight hundred thirty-seven (16%) had their ICM implanted following a stroke. Four thousand and three hundred forty-three (39%) participants did not have a known AF diagnosis and only a minority had pre-existing heart failure or ischemic heart disease. Cohort demographics and relative prevalence of indications for ICM implantation are described in Table 1 of the original manuscript. The clinical significance of episode-level characteristics of AF events in patients with transvenous cardiac devices has been previously reported [1]. Our analysis is the largest study of this in participants with ICMs, demonstrating utility in this population. A prospective trial of long-term rhythm monitoring using wearable ECGs that will report AF event characteristics in a population without cardiac devices shall contribute further to our understanding of the interpretation of these parameters as well (Clinicaltrials.gov IDNCT05016791).