Association of fragmented QRS with left atrial scarring in patients with persistent atrial fibrillation undergoing radiofrequency catheter ablation.

Background: Fragmented QRS (fQRS) on 12-lead electrocardiography is a noninvasive marker of intramyocardial conduction delay due to ventricular scarring that has not previously been studied in atrial fibrillation.
Objective: The purpose of this study was to assess the association of fQRS with left atrial (LA) scarring in patients with persistent atrial fibrillation (PsAF) undergoing first catheter ablation.
Methods: A total of 376 patients with PsAF were enrolled. Severity of LA scarring was assessed using electroanatomic mapping. Narrow fQRS was defined by the presence of an additional R wave (R') or notching in the nadir of the S wave, or the presence of >1 R' in 2 contiguous leads corresponding to inferior, lateral, or anterior myocardial regions.
Results: Both any degree (97.3% vs 63.3%) and severe (42.2% vs 6.3%) LA scarring were higher in patients with fQRS. Age and fQRS were found to be independent predictors of severe LA scarring. At multiple ventricular regions, fQRS had diagnostic accuracy of 79.8% for prediction of severe LA scarring. Nonpulmonary vein triggers were more often detected and ablated in patients with fQRS and severe LA scarring (84.4% vs 70%; P = .001). Atrial tachyarrhythmia recurrence was observed in 131 patients (34.8%) during 18.9 ± 7.7 months of follow-up, which was significantly higher in patients with fQRS (53.2% vs 16.8%). In multivariate analysis, fQRS was found to be a significant predictor of recurrence (hazard ratio 4.65; 95% interval confidence 2.91-7.42; P <.001).
Conclusion: The study results showed that fQRS is a simple, available, and noninvasive marker, and that fQRS at multiple ventricular regions is significantly associated with the severity of LA scarring in PsAF patients.
(Copyright © 2019 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)