Characterisation of ablation strategies at redo catheter ablation for atrial fibrillation and predictors of arrhythmia recurrence: results from the AFREDO registry
Authors: Hoevelmann J , Kiehm A , Viljoen C A , Pavlicek V , Boehm M , Ukena C 
Published: May 2024

Abstract

Background
Patients who have undergone prior pulmonary vein isolation (PVI) for atrial fibrillation (AF) often require a repeat ablation for AF recurrence. The optimal ablative strategy for the redo procedure and predictors of AF recurrence thereafter remain largely unknown.

Purpose
We aimed to characterise the ablation strategies applied at re-PVI and identify possible predictors of AF recurrence.

Methods
Our single-centre, retrospective study included all consecutive patients who underwent first redo PVI at our centre from 2017 to 2022. Inclusion criteria required at least one available follow-up visit within the first 12 months after the redo procedure. Ablation strategies of the initial and redo procedure were captured. Kaplan-Meier curves were used to illustrate time of AF recurrence, as classified by predictors of outcome determined by multivariable regression analyses.

Results
We included 215 patients (39.1% female) with a median age of 66.6 years (IQR 58.6-73.2) at the time of redo procedure. The initial PVI was cryoablation in 39.9%, RFA in 57.7% and surgical ablation in 2.4%. After the initial procedure, 55.8% had paroxysmal AF and 44.2% had persistent AF. At the redo procedure, 25.1% of patients were found to have no PV reconnection, whereas 20.5% had a single reconnected PV, and 54.4% had two or more reconnected PVs. A left-sided flutter ablation was performed in 18.8%, a left atrial (LA) roof line in 16.9%, a posterior mitral isthmus line in 5.2%, an anterior mitral isthmus line in 27.9%, and a posterior box lesion in 8.4%. Overall, 34.4% of patients showed areas of low-voltages in the redo procedure. Patients with areas of low voltages were less likely to have any reconnected PVs in the redo-procedure (p&lt;0.001). After the second ablation procedure, 54.0% experienced AF recurrence. Univariable regression analysis revealed moderate (p=0.006) or severe (p= 0.015) LA dilatation, persistent AF (p=0.005), and posterior LA low voltage areas (p=0.011) as significant predictors of AF recurrence after the redo procedure. The number of reconnected PVs at the re-PVI did not predict AF recurrence (p=0.1090). As illustrated in Fig. 1 and 2, patients with paroxysmal AF experienced less AF recurrence compared to those with persistent AF (log-rank p=0.0025). Moreover, moderate or severe LA dilatation at baseline was associated with more frequent AF recurrences (log-rank p=0.0279).

Conclusion
A significant proportion of patients undergoing re-PVI experienced AF recurrence. We found that persistent AF and moderate or severe LA enlargement emerged as significant predictors of AF recurrence after the redo procedure. Although PV reconnection was observed in more than two thirds of patients at the re-PVI, it did not predict AF recurrence thereafter. However, patients without PV reconnection had significantly more low-voltage areas, which may be indicative of a different AF recurrence mechanism in this subgroup.Figure 1:Type of AFFigure 2:LA dilatation