Introduction: The effectiveness of pulmonary vein isolation (PVI) has lead to a rising number of patients with recurrent atrial fibrillation (AF) despite persistent PVI. The correct approach in these cases remains controversial. Thus, we aimed at evaluating the efficacy of different ablation strategies on AF recurrence and patient satisfaction in patients with recurrent AF despite persistent PVI after primary Cryoballoon ablation.

Methods and results: From a prospective single centre register, we identified a total of 29 patients (mean age: 61 ± 11 years; mean BMI: 27± 4 kg/m²; mean LAVI: 37± 9 ml/m², mean CHA₂DS₂-Vasc score: 2 ±1; mean left ventricular ejection fraction: 56± 8 %) which underwent a redo procedure for recurrent AF after an index PVI with the 2^nd generation Medtronic Cryoballoon despite persistent isolation of all PVs. Redo procedures were performed with high density 3D Mapping systems and single tip RF catheters. All patients showed a moderate degree of left atrial (LA) scarring (Voltage ≤ 0,5 mV). At the operator’s discretion we performed a substrate-based ablation (n = 23) or a wide antral circumferential enlargement of the ablation lesion (n = 6). The patients were followed in our outpatient program and contacted via phone for follow-up 1.5 ± 0.7 years after the redo procedure. None of the patients suffered short- or long-term procedure related complications. Based on a quality-of-life (QoL) questionnaire 87.5 % of the patients who underwent a substrate-based ablation (3 patients remained on amiodarone, 2 on flecainide and 3 on dronedarone) and 80 % of the patients who received an empirical enlargement of the circumferential ablation lines (1 patient remained on amiodarone and 1 on flecainide) reported a significant decrease in AF related symptoms.  However, in patients with a gain in QoL, after a blanking period of 3 months following the redo procedure, at least one symptomatic AF recurrence in the substrate-based ablation group (57%) and the enlargement of the circumferential ablation lines group (100%) occurred.

Conclusions: In this prospective observational study of patients with symptomatic AF recurrence despite persistent PVI after an index Cryoballoon ablation and a comparable degree of LA scarring, a greater percentage of patients report a gain in QoL in the substrate-based ablation group. However, during a mean follow-up of about 1,5 years a relevant percentage of our patients who reported a gain in QoL still showed at least one symptomatic episode of AF. This illustrates the limitations of endpoints in AF and underlines the importance of assessing quality of life and most likely AF burden in ongoing studies.