Introduction: For patients with persistent atrial fibrillation (PeAF), pulmonary vein isolation (PVI) remains the standard of care, although outcomes are often sub-optimal. AcQMap is a novel non-contact high resolution imaging and AF mapping system using dipole density mapping to identify areas triggering and maintaining AF.
Purpose: This two-centre retrospective observational study aimed to assess whether combined Cryoballoon PVI and AcQMap-guided
non-PVI ablation resulted in improved outcomes compared with Cryoballoon PVI alone or Carto-guided radiofrequency (RF) ablation in patients undergoing first time ablation for PeAF.
Methods: Data was collected from all patients who underwent first time ablation for PeAF at Freeman Hospital in Newcastle upon Tyne and Liverpool Heart and Chest Hospital between August 2016 and June 2018 with a minimum of 6 months of follow-up data. The use of combined AcQMap/Cryoballoon, Cryoballoon alone or Carto-guided PVI (with or without additional linear lesions) was as per operator preference. The primary endpoint was AF/atrial tachycardia (AT) recurrence after a 3-month blanking period.
Results: Two-hundred-and-seventeen patients (79% male, mean age 62 ± 10 years, 19.9% with severe LA dilatation, mean CHA2DS2-VASc score 1.48 ± 1.22) were included for analysis. Mean follow-up was 350 ± 122 days and was similar between the 3 groups, as were patient characteristics. Outcomes from the three strategies are shown in Table 1.
AF/AT recurrence following the initial procedure was similar for AcQMap/Cryoballoon and Carto-guided RF ablation (43% versus 46%). However, there were strong trends towards a higher recurrence rate with Cryoballoon alone (61%) when compared to these technologies, although these did not reach statistical significance (P=0.078 and P=0.058, respectively). In patients with arrhythmia recurrence following
AcQMap/Cryoballoon, this was most commonly AT (60%) rather than AF, whereas AF predominated following Cryoballoon only (94%) or Carto-guided ablation (94%). Overall success rates (after including redo procedures) were superior following an initial procedure with
AcQMap/Cryoballoon (73%) or Carto-guided RF (66%) compared to Cryoballoon alone (48%; p=0.017 and p=0.028, respectively).
Conclusion: Our two-centre real-world observational study showed similar first procedure outcomes with AcQMap/Cryoballoon and Carto-guided PVI ± substrate modification, with a strong trend towards inferior outcomes for Cryoballoon alone and significantly lower success rates for this technology after including redo procedures. Recurrence following AcQMap was most commonly AT, which may have contributed to improved outcomes being achieved after including redo procedures. Randomised controlled trials will be required to evaluate the efficacy of this costlier combined initial procedure against existing treatment modalities.