Abstract 9683: Indexed Left Atrial Volume Predicts the Presence of Low Voltage Areas. The ZAQ Score

IntroductionPulmonary vein isolation (PVI) is the most efficient therapy for patients (pts) with paroxysmal atrial fibrillation (AF) and is the primary endpoint for almost all AF ablation procedures. In pts with advanced structural changes (both paroxysmal and persistent AF), substrate modification may be required although the ideal ablation strategy is still debated. Therefore, it would be helpful to assess the presence of substrate in the left atrium (LA) before the ablation. Late gadolinium enhancement MRI and electroanatomic voltage mapping (EVM) have been used for substrate characterization. Whereas the former is difficult to reproduce using standard MRI software, the latter does not allow to plan an ablation strategy before the procedure. Clinical parameters (combined in a score, e.g. DRFLASH) have been proposed as a way to predict the presence of atrial substrate, and increased LA volume is associated with higher rates of AF recurrence both with drug and ablation.HypothesisWe hypothesized that (1) indexed LA volume (LAVI) is associated with the presence of low voltage areas (LVA) identified by EVMin the left atrium and (2) that it would be helpful in developing a score that would predict the need for additional substrate modification during ablation.MethodsWe defined the cut-off value of LAVI and age which had the best accuracy to detect LVA in receiver operating characteristic curve (ROC). Clinical predictors for the presence of LVA were identified with regression analysis. These parameters were used to build a risk score (Zentralklinik Bad Berka and University of L’Aquila [ZAQ] Scoreage>65 years, female gender and LAVI>57ml/m).Results374 patients (age 62±10 years, 149 female, 222 paroxysmal AF, EF 0.56±7, LA diameter 40±5mm) were studied. The mean LA volume was 117±29ml, LAVI 58±14ml/m. In our study court, the ZAQ score correctly identified the 75 pts with LVA (AUC 0.81; CI 0.76-0.86; P