Impact of high-resolution 3D-mapping with micro-electrodes on catheter ablation of Wolff-Parkinson-White syndrome

Background: It is currently unknown whether high-resolution 3D-mapping and micro-electrodes add meaningful benefits in catheter ablation of Wolff-Parkinson-White (WPW) syndrome and challenging, e.g. para -Hisian accessory pathways (APs). Objectives: To compare the mapping resolution, acute success and complication rates in patients with WPW syndrome undergoing a first-time catheter ablation using only a contact force-sensing ablation catheter for mapping or a multi-electrode high-resolution mapping catheter. Methods: Fifty consecutive 3D-mapping procedures for WPW syndrome using a 3.5-mm ablation catheter (n = 27) or a multi-electrode high-resolution catheter (n = 23) were retrospectively analyzed regarding mapping resolution defined as first 5/10 msec isochronal activation area, number of RF applications to achieve AP block, occurence of AP automaticity during RF delivery, and acute success and complication rates. Results: Catheter ablation was successful in 48/50 patients with a median of 1 (IQR 1 - 2) RF applications. Compared to ablation catheter mapping, high-resolution mapping showed a significantly smaller isochronal activation area in the first 5/10 msec (1.25 +/- 0.29 vs 0.15 +/- 0.03 cm (2 ); P < 0.001 and 3.41 +/- 0.58 vs 0.55 +/- 0.12 cm (2 ); P < 0.0001) and significantly higher incidence of AP automaticity during RF delivery (0 vs 22 %; P < 0.05). In para -Hisian APs, micro-electrodes recorded distinct His electrograms and AP potentials without fusion and without AP bumping permitting safe and effective para -Hisian AP ablation. Conclusions: High-resolution mapping increases the mapping accuracy of the AP and its insertion site leading to a significantly higher incidence of AP automaticity during RF delivery. Micro-electrodes provide clinically relevant advantages in para -hisian AP mapping improving efficacy and safety of para -Hisian AP ablation.