High-Density Grid Catheter for Detailed Mapping of Sinus Rhythm and Scar-Related Ventricular Tachycardia: Comparison With a Linear Duodecapolar Catheter

Objectives: This study aimed to evaluate the feasibility and accuracy of using a novel grid mapping catheter during scar-related ventricular tachycardia (VT) ablation. Background: Ultra–high-density (UHD) mapping improves identification of local abnormal ventricular activities (LAVAs) and characterization of scar substrates. Methods: Consecutive patients underwent endocardial and/or epicardial ablation guided by a HD grid mapping catheter. A linear duodecapolar catheter was used in the initial cases for systematic correlation. Isochronal late activation mapping was performed during sinus rhythm to identify deceleration zones, and activation mapping of VT was performed when tolerated. Results: In 38 patients, 51 electroanatomic maps (left ventricle: 26, epicardium: 21, right ventricle: 4) were created using a grid catheter. LAVAs were identified in 98% of cases and deceleration zones were observed in 86%. High-frequency electrograms with diastolic activation were identified during 44 sustained monomorphic VTs, and the critical isthmus was colocalized to deceleration zones during sinus rhythm in 96% of cases. In 17 cases that underwent sequential mapping with both grid and linear catheters, the low voltage area detected using the grid (HD wave) was significantly smaller, with ratios of 0.61 (<0.5 mV) and 0.81 (<1.5 mV) relative to the duodecapolar catheter. Conclusions: VT ablation guided by a novel HD grid catheter is safe and feasible for clinical use in human scar-related VT via both endocardial and epicardial approaches. Automated selection of larger bipolar amplitudes among orthogonal pairs consistently displayed smaller low voltage areas than a previously validated linear catheter.