A Novel Score using Left Atrial Volume Index, Gender, and Age to Predict the Presence of Left Atrial Low Voltage Zones in Patients with Atrial Fibrillation: the ZAQ score

Background: Pulmonary vein isolation (PVI) is the cornerstone of catheter ablation in patients with atrial fibrillation (AF). However, in presence of advanced left atrial structural changes, additional targeted catheter ablation of left atrial low voltage zones (LVZs) showed favorable results. Therefore, with the advent of single-shot techniques, it would be helpful to predict the presence of LVZs beforehand. Objective: This study hypothesized that computed tomography derived (CT) left atrial volume index (LAVI) in combination with objective parameters is able to predict the presence of LVZs. Methods: In a large cohort of patients undergoing first AF ablation, comprehensive echocardiographic evaluation and contrast-enhanced cardiac CT for pulmonary vein anatomy delineation, and LA volume quantification were performed. During an electrophysiology study, three-dimensional (3D) LA geometry and EAVM were created. Zones with bipolar peak-to-peak voltage amplitudes <0.5 mV were defined as LVZs. Results: In the derivation cohort of 374 patients, predictors for the presence of LVZs were identified with regression analysis and used to build the ZAQ risk score (age≥65 years, female gender and LAVI≥57ml/m2). The ZAQ score with a cut-off value of 2 points correctly identified the patients with and without LVZs (AUC 0.809; 95% CI 0.758- 0.861; p<0.001). In the validation cohort of 103 patients, the predictive value of the ZAQ score was confirmed (AUC 0.786; 95% CI 0.700-0.827; p<0.001). Conclusions: The ZAQ score accurately identifies patients with or without LVZs and may be helpful to plan the ablation strategy ahead of time (i.e. single shot PVI vs 3D mapping-guided ablation).