Fastest pulmonary vein atrial fibrillation cycle length Identifies PVI responders beyond clinical atrial fibrillation pattern: the FARS-AF II study

Background Atrial fibrillation cycle length (AF CL) measured in the pulmonary veins (PV) with a novel simple method (the average of the 10 consecutive Fastest Atrial Repetitive Similar signal interval [FARS10]) accurately identified pulmonary vein isolation (PVI) responders in a preliminary study. Aim To evaluate differences in PV-FARS10-AF CL between paroxysmal and persistent AF and to define the optimal cutoff to predict PVI-only approach success in a large population. Methods We prospectively enrolled consecutive patients with persistent or paroxysmal AF undergoing first PVI in a single center study. The primary endpoint was atrial arrhythmia recurrence. Results 219 patients (61.8 ± 11.2 years, 25.1% female) were included, with 70 patients (32%) having paroxysmal AF and 149 patients (68%) persistent AF. After a median follow-up of 18.0 (IQR 10.2 – 42.3) months, 72 (32.9%) patients experienced AF/AFL/AT recurrence. Patients with PV-FARS10-AF CL ≤155ms had a lower rate of AF/AFL/AT recurrence compared to those with PV-FARS10-AF CL >155ms in the overall population (HR 0.34, p < .001), in persistent AF (HR 0.40, p = .002) and in paroxysmal AF (HR 0.18, p = .01). In multivariable analysis – which included age, sex, BMI, CHA2DS2-VA score, obstructive sleep apnea syndrome (OSAS), duration of AF, AF type (paroxysmal vs. persistent), left ventricular ejection fraction (LVEF), left atrial volume index (LAVI), and AF termination during ablation – only the fastest PV-FARS10-AF CL ≤155ms was significant predictor of AF/AFL/AT recurrence free survival in the overall population (HR 0.45, CI: 0.26-0.78, p = .005). Paroxysmal AF patients more frequently had fastest PV-FARS10-AF CL ≤155ms than persistent AF patients (61.4% vs 42.3%, p = .009). Conclusion PV-FARS10-AF CL can accurately identify PVI-responders among patients with persistent and paroxysmal AF. Patients with slow PV-FARS10-AF CL (> 155ms) experience a higher rate of AF/AFL/AT recurrence after PVI only approach. The fastest PV-FARS10-AF CL ≤ 155ms occurs more frequently in paroxysmal AF patients than in persistent AF patients.