A Critical Perspective on the Role of Catheter Ablation in Management of Atrial Fibrillation

Optimal substrate modification strategies using catheter ablation in patients with persistent atrial fibrillation: 3-year follow-up outcomes

Objectives

This study aimed to assess the comparative efficacy of four ablation strategies on the incidence rates of freedom from atrial fibrillation (AF) or atrial tachycardia (AT) through a 3‐year follow‐up in patients with persistent AF.

Background

The optimal substrate modification strategies using catheter ablation for patients with persistent AF remain unclear.

Methods

Patients with persistent AF were enrolled consecutively to undergo each of four ablation strategies: (a) Group 1 (Gp 1, n = 69), pulmonary vein isolation (PVI) plus rotor ablation assisted by similarity index and phase mapping; (b) Gp 2 (n = 75), PVI plus linear ablations at the left atrium; (c) Gp 3 (n = 42), PVI plus the elimination of complex fractionated atrial electrograms; (d) Gp 4 (n = 67), PVI only. Potential confounders were adjusted via a multivariate survival parametric model.

Results

Baseline characteristics were similar across the four groups. At a follow‐up period of 34.9 ± 38.6 months, patients in Gp 1 showed the highest rate of freedom from AF compared with the other three groups (p = .002), while patients in Gp 3 and 4 showed lower rates of freedom from AT than those of the other two groups (p = .006). Independent predictors of recurrence of AF were the ablation strategy (p = .002) and left atrial diameter (LAD) (p = .01).

Conclusion

In patients with persistent AF, a substrate modification strategy using rotor ablation assisted by similarity index and phase mapping provided a benefit for maintaining sinus rhythm compared with the other strategies. Both ablation strategy and baseline LAD predicted the 3‐year outcomes of freedom from AT/AF

Approaches to catheter ablation for persistent atrial fibrillation

BACKGROUND

Catheter ablation is less successful for persistent atrial fibrillation than for paroxysmal atrial fibrillation. Guidelines suggest that adjuvant substrate modification in addition to pulmonary-vein isolation is required in persistent atrial fibrillation.

METHODS

We randomly assigned 589 patients with persistent atrial fibrillation in a 1:4:4 ratio to ablation with pulmonary-vein isolation alone (67 patients), pulmonary-vein isolation plus ablation of electrograms showing complex fractionated activity (263 patients), or pulmonary-vein isolation plus additional linear ablation across the left atrial roof and mitral valve isthmus (259 patients). The duration of follow-up was 18 months. The primary end point was freedom from any documented recurrence of atrial fibrillation lasting longer than 30 seconds after a single ablation procedure.

RESULTS

Procedure time was significantly shorter for pulmonary-vein isolation alone than for the other two procedures (P<0.001). After 18 months, 59% of patients assigned to pulmonary-vein isolation alone were free from recurrent atrial fibrillation, as compared with 49% of patients assigned to pulmonary-vein isolation plus complex electrogram ablation and 46% of patients assigned to pulmonary-vein isolation plus linear ablation (P=0.15). There were also no significant differences among the three groups for the secondary end points, including freedom from atrial fibrillation after two ablation procedures and freedom from any atrial arrhythmia. Complications included tamponade (three patients), stroke or transient ischemic attack (three patients), and atrioesophageal fistula (one patient).

CONCLUSIONS

Among patients with persistent atrial fibrillation, we found no reduction in the rate of recurrent atrial fibrillation when either linear ablation or ablation of complex fractionated electrograms was performed in addition to pulmonary-vein isolation. (Funded by St. Jude Medical; ClinicalTrials.gov number, NCT01203748.).

Staged transthoracic approach to persistent atrial fibrillation (TOP-AF): study protocol for a randomized trial

Background

Persistent atrial fibrillation frequently shows multiple different electrophysiological mechanisms of induction. This heterogeneity causes a low success rate of single procedures of ablation and a high incidence of recurrence. Surgical ablation through bilateral thoracotomy demonstrates better results after a single procedure. Prospective observational studies in inhomogeneous populations without control groups report a remarkable 90% of success with hybrid or staged procedures of surgical ablation coupled with catheter ablation. In this trial, we will examine the hypothesis that a staged approach involving initial minimally invasive surgical ablation of persistent atrial fibrillation, followed by a second percutaneous procedure in case of recurrence, has a higher success rate than repeated percutaneous procedures.

Methods/Design

This is a controlled (2:1) randomized trial comparing use of a percutaneous catheter with minimally invasive transthoracic surgical ablation of persistent atrial fibrillation. The inclusion and exclusion criteria, definitions, and treatment protocols are those reported by the 2012 Expert Consensus Statement on catheter and surgical ablation of atrial fibrillation. Patients will be randomized to either percutaneous catheter (n = 100) or surgical (n = 50) ablation as the first procedure. After 3 months, they are re-evaluated, according to the same guidelines, and receive a second procedure if necessary. Crossover will be allowed and data analyzed on an “intention-to-treat” basis. Primary outcomes are the incidence of sinus rhythm at 6 and 12 months and the proportions of patients requiring a second procedure.

Discussion

The use of a staged strategy combining surgical and percutaneous approaches might be more favorable in treatment of persistent atrial fibrillation than the controversial single percutaneous ablation.

Trial registration

ISRCTN08035058 Reg 06.20.2013