Ultra-high Density Mapping With Multielectrode Catheter vs Conventional Point by Point Mapping for Ventricular Tachycardia Substrate Ablation

This is a prospective, randomized controlled study. Twenty patients with sustained ventricular tachycardia and structurally abnormal ventricle(s) will be prospectively enrolled. In all patients a detailed pre and post-ablation electroanatomical mapping will be performed, and these maps will be merged with CT and/or MRI images. Patients will be randomly assigned to two groups. In Group A patients both pre and post-ablation mapping will be performed firstly by conventional point by point mapping using a Navistar Thermocool catheter, and secondly by multielectrode contact mapping using a Pentaray catheter. In this group, target ablation sites will be guided by point by point map. In Group B patients, both pre and post-ablation mapping will be performed firstly by multielectrode contact mapping using a Pentaray catheter, and secondly by conventional point by point mapping using a Navistar Thermocool catheter. In this group target ablation sites will be guided by multielectrode contact mapping.

Slow conduction channels will be identified by color-coded voltage map adjustment of the lower and upper thresholds and also the presence of fractioned electrograms with the delayed component showing sequential orthodromic activation. The entrances of these channels will be the target of the ablation sites (scar dechanneling technique).