Computed Tomography-Derived Left Atrial Volume Index, Gender, and Age to Predict the Presence and the Extent of Left Atrial Low Voltage Zones in Patients with Atrial Fibrillation: the ZAQ Score.

BACKGROUND: Pulmonary vein isolation is the cornerstone of catheter ablation in patients with atrial fibrillation (AF). However, with advanced left atrial (LA) structural changes, additional targeted catheter ablation of low voltage zones (LVZs) has produced favorable results. Therefore, with the advent of single-shot techniques, it would be helpful to predict the presence of LVZs before an ablation procedure.

OBJECTIVE: We hypothesized that computed tomography-derived (CT) left atrial volume index (LAVI), in combination with other objective parameters, could be used to develop a score able to predict the presence of LVZs.

METHODS: In a large cohort of patients undergoing their first AF ablations, comprehensive echocardiographic evaluations and cardiac CT were performed. During the electrophysiological studies, LA geometry and electro-anatomic voltage maps were created. LVZs were defined as areas ≥1cm2 with bipolar peak-to-peak voltage amplitudes ≤0.5 mV.

RESULTS: In a derivation cohort of 374 patients, predictors of LVZs were identified by regression analysis and used to build the ZAQ score (age≥65 years, female gender and CT LAVI≥57ml/m2 ). The ZAQ score of 2 points accurately identified the presence and the extent of LVZs (AUC 0.809, 95% CI 0.758-0.861, p<0.001; 3 cm2 [IQR 1.5-4.5] vs 7 cm2 [IQR 4-9], p 0.001). In a validation cohort of 103 patients, the predictive value of the score was confirmed (AUC 0.793, 95% CI 0.709-0.878, p<0.001; 4 cm2 [IQR 2-7] vs 11.5 cm2 [IQR 8-16.5], p 0.001).

CONCLUSIONS: The ZAQ score identifies LVZs and may be useful for planning the ablation strategy ahead of time. This article is protected by copyright. All rights reserved.