Left atrial deceleration outperforms regional conduction velocity in predicting arrhythmia recurrence following atrial fibrillation ablation.

Background: The slowest regional conduction velocity (CV) is associated with atrial arrhythmia (AA) recurrence following atrial fibrillation (AF) ablation; however, the role of conduction deceleration has not been investigated.

Objective: The study sought to assess whether true deceleration (TD) is a better marker than CV in identifying abnormal left atrial (LA) substrate and AA recurrence in patients undergoing de novo pulmonary vein isolation (PVI).

Methods: Eighty AF patients and 6 control subjects underwent LA electroanatomic mapping during atrial pacing. The LA was divided into 6 anatomical regions and the regional low-voltage area (LVA), CV, and maximum true deceleration (TD) were quantified. TD was calculated as the largest continuous decline in CV along the propagating wavefront divided by the change in activation time. AF patients underwent PVI and AA recurrence was assessed during 12-month follow-up.

Results: A median of 1 to 2 TDs were found in each LA region of AF patients, and the TD only weakly correlated with the regional CV. AF patients with AA recurrence had a significantly larger LVA, lower CV, and greater TD on the anterior wall. Multivariate modeling demonstrated that the TD (when >110 m/s) and not the CV (when <0.2 m/s) predicted AA recurrence (C-statistic = 0.74). Clinical TD sites (defined as TD >110 m/s) only colocalized with LVA sites in a minority of LA regions (range 13%-44%) and were absent from control subjects.

Conclusion: TD is a novel metric for quantifying LA remodeling and predicting AA recurrence post-PVI that outperforms CV. This may guide future trials focusing on improving success from substrate-based AF ablation.