Comparison of the residual unipolar voltage following left atrial posterior wall isolation with radiofrequency and cryoballoon catheters for persistent atrial fibrillation

Abstract

Background: Achieving transmural lesions during left atrial posterior wall isolation (LAPWI) is challenging, and the differences in lesion transmurality between radiofrequency ablation (RFA) and cryoballoon ablation (CBA) remain unclear. Endocardial unipolar voltage mapping is reported to be more sensitive than bipolar voltage mapping for detecting intramural viable myocardium, with 1.08 mV as the cutoff threshold in the atria.

Objective: The purpose of this study was to compare the residual unipolar LAPW potentials after LAPWI of persistent atrial fibrillation (PersAF) between RFA and CBA and assess their association with atrial arrhythmia recurrence.

Methods: We enrolled 183 patients with PersAF who underwent pulmonary vein isolation (PVI) and LAPWI, both evaluated as successful using bipolar voltage mapping. Among them, 97 underwent RFA (RFA group) and 86 CBA (CBA group). Residual unipolar LAPW potentials >1.08 mV were analyzed, along with residual potential area, maximum voltage, and arrhythmia recurrence rates.

Results: Residual LAPW unipolar potentials >1.08 mV were more common in the RFA group than CBA group (29.9% vs 15.1%; P = .018), with larger potential areas (1.7 ± 3.6 cm² vs 0.25 ± 0.69 cm²; P <.001) and higher maximum voltages (0.83 ± 0.41 mV vs 0.69 ± 0.32 mV; P = .0093). The 1-year atrial arrhythmia recurrence rate was higher in the RFA group patients with residual LAPW potentials (36.1% vs 18.0%; P = .033), whereas no significant difference was observed in the CBA group (15.4% vs 18.7%; P = .98).

Conclusion: Residual unipolar LAPW potentials were more prevalent and associated with arrhythmia recurrence following RFA, whereas those residual potentials had no significant impact on recurrence after CBA.

Keywords: Atrial fibrillation; Catheter ablation; Cryoballoon ablation; Left atrial posterior wall isolation; Radiofrequency ablation.