Loop Recorder Detected High Rate of Atrial Fibrillation Recurrence after a Single Balloon- or Basket-Based Ablation of Paroxysmal Atrial Fibrillation: Results of the MACPAF Study

Abstract

Purpose: Pulmonary vein isolation (PVI) is an established approach to treat symptomatic non-permanent atrial fibrillation (AF). Detecting AF recurrence after PVI is important, if discontinuation of oral anticoagulation after ablation is considered.

Methods: Patients with symptomatic paroxysmal AF were enrolled in the prospective randomized mesh ablator vs. cryoballoon pulmonary vein (PV) ablation of symptomatic paroxysmal AF study, comparing efficacy and safety of the HD Mesh Ablator® (C.R. Bard, Lowell, MA, USA) and the Arctic Front® (Medtronic, Minneapolis, MN, USA) catheter. Rhythm status post-PVI was closely monitored for 1 year using the implantable loop recorder (ILR) Reveal XT® (Medtronic Minneapolis, MN, USA).

Results: The study was terminated after the first interim analysis due to the inability of the HD Mesh Ablator® to achieve the predefined primary study endpoint, an exit block of all PVs. After a 90-day blanking period, 23 (62.2%) out of 37 study patients (median 63.0 years; 41% females) had at least one episode of AF. AF recurrence was associated with AF episodes during the blanking period {hazard ratios (HR) 5.10 [95% confidence interval (CI) 1.21-21.4]; p = 0.038}, and a common left-sided PV ostium [HR 4.17 (95%CI 1.48-11.8); p = 0.039] but not with catheter type, age, gender, cardiovascular risk profile, or left atrial volume. There was a trend toward AF recurrence in patients without complete PVI of all PV (p = 0.095). Overall, 337 (59.4%) out of 566 ILR-detected episodes represented AF. Comparing patients with AF recurrence to those without, there was no difference in cognitive performance 6 months post-ablation.

Conclusion: Using an ILR, in more than 60% of all patients with paroxysmal AF, a recurrence of AF was detected within 12 months after ablation. In patients with a common PV ostium, the first generation balloon-based catheter is obviously less effective.

Clinical trials: http://Clinicaltrials.gov NCT01061931.

Keywords: Arctic Front®; ECG monitoring; HD Mesh Ablator®; atrial fibrillation; catheter ablation; pulmonary veins.

Figures

Figure 1

Atrial fibrillation (AF)-free survival after pulmonary vein isolation (PVI) according to (A) achieved exit block of all pulmonary veins (PVs) during first PVI (p = 0.086) and (B) used catheter device (p = 0.547).

Figure 2

Boxplots of (A) automatically detected atrial fibrillation (AF) burden (%) by the implantable loop recorder and (B) computed AF burden of verified AF episodes pre-ablation and during follow-up. p values computed by the Wilcoxon signed-rank test (dotted line pre-ablation vs. day 180 post-ablation and solid line pre-ablation vs. day 365 post-ablation).