Clinical implications of redefining recurrence of atrial fibrillation following catheter ablation

In the LINQ AF study published in the November 2018 issue of EP Europace, Wechselberger et al.1 demonstrated the utility of insertable cardiac monitors (ICMs) for monitoring after atrial fibrillation (AF) ablation. The authors conclude that AF episodes <6 min are rare and of questionable clinical relevance, and suggest revision of the current definition of AF recurrence to duration >6 min and AF burden >10 min/week. We agree that brief episodes of AF are of uncertain thromboembolic risk and that ICMs offer unique advantages with regards to arrhythmia monitoring. We would however caution against premature abandonment of current guidelines and argue that further studies in this area are needed. Departure from the current HRS/EHRA consensus definition of AF recurrence after ablation (>30 s)2 and adoption of more liberal cut-offs may give false comfort in obviating the use of oral anticoagulant (OAC) therapy, and may lead to the routine use of ICMs for AF monitoring post-ablation. These devices have been better studied for unexplained syncope and detection of subclinical AF after stroke and are not universally used in practice following AF ablation.3 Only one small observational study (N = 65) from Zuern et al.4 has described use of ICMs following AF ablation to guide OAC management. The authors showed that two-thirds of patients in this cohort were able to remain off OAC post-AF ablation based on low AF burden as detected by ICMs. While these findings are promising, we should remember that reduction in stroke risk following AF ablation has not been observed in randomized data. Furthermore, discontinuation of OAC after AF ablation is currently not recommended in the guidelines in patients with high CHA2DS2-VASc scores, regardless of procedural success. The forthcoming REACT-AF and OCEAN randomized controlled trials may inform future practice.5 Until more data are available demonstrating improvement in meaningful outcomes and cost-effectiveness of more liberal cut-offs for AF recurrence, we should continue to support the current guidelines. Conflict of interest: J.C.H. has received honoraria from Medtronic, Abbott, Boston Scientific, Biotronik, Janssen Pharmaceutical, Bristol-Myers Squibb, and Biosense-Webster and has received research grants from Biosense-Webster and Biotronik. All other authors declared no conflict of interest.