An improved window of interest for electroanatomical mapping of atrial tachycardia

Abstract

Diagnosis of atrial tachycardia (AT) with 3D mapping system remains challenging due to fibrosis or previous ablation. This study aims to evaluate a new electroanatomical mapping annotation setting using a window of interest (WOI) adjusted at the end of the P-wave to identify the AT mechanism more accurately. Twenty patients with successful ablation of left AT using navigation system CARTO3 were evaluated. Two maps for each patient were generated offline using either conventional settings of WOI or WOI set at the end of the P-wave. Three investigators from two centres analysed the maps blindly. Mechanisms of AT were macroreentrant in 14/20 patients (70%) and focal in 6/20 (30%). WOI set at the end of the P-wave resulted in a significant increase in the percentage of correct identifications of the mechanism in 93.3 ± 13.7% vs. 58.3 ± 33.9% ( P = 0.0003) with conventional WOI. Diagnoses were performed significantly faster (27.8 ± 16.4s vs. 38.97 ± 13.65s, respectively; P = 0.0231) and with a greater confidence in the diagnosis (confidence index 2.56 ± 0.46 vs. 2.12 ± 0.45, respectively; P = 0.0024). Interestingly, in perimitral AT maps obtained with the investigational setting, “early meets late” were located closer to the anatomical region of the mitral isthmus (15.9 ± 20.9 mm vs. 48.77 ± 23.23 mm, respectively; P = 0.0028). This study found that electroanatomical mapping acquisition with a WOI set at the end of the P-wave improves the ability to diagnose the arrhythmia mechanism. It is particularly beneficial in identifying perimitral ATs.