Left atrial substrate characterization based on bipolar voltage electrograms acquired with multipolar, focal and mini-electrode catheters- the CHAZE-Substrate study

BackgroundBipolar voltage (BV) electrograms for left atrial (LA) substrate characterization depend on catheter design and electrode configuration. The aim of the study was to investigate the relationship between the BV amplitude (BVA) using four different catheters and to identify their specific LA cutoffs for scar and healthy tissue. MethodsConsecutive high-resolution electroanatomic mapping was performed using a multipolar Orion catheter (Orion-map), a duo-decapolar variable circular mapping catheter (Lasso-Map) and an irrigated focal ablation catheter with minielectrodes (Mifi-map). Virtual remapping using the Mifi-map was performed with a 4.5 mm tip-size electrode configuration (Nav-map). BVAs were compared in voxels of 3x3x3 mm3. The equivalent BVA cutoff for every catheter was calculated for established reference cutoff values of 0.1 mV, 0.2 mV, 0.5 mV, 1.0 mV, and 1.5 mV. ResultsWe analyzed 25 patients (72% men, age 68{+/-}15 years). For scar tissue, a 0.5 mV cutoff using the Nav corresponds to a lower cutoff of 0.35 mV for the Orion and of 0.48 mV for the Lasso. Accordingly, a 0.2 mV cutoff corresponds to a cutoff of 0.09 mV for the Orion and of 0.14 mV for the Lasso. For a healthy tissue cutoff at 1.5 mV, a larger BVA cutoff for the small electrodes of the Orion and the Lasso was determined of 1.68 mV and 2.21 mV, respectively. ConclusionsWhen measuring LA BVA in scar and healthy tissue, relevant differences were seen between focal, multielectrode and mini-electrode catheters. Adapted cutoffs for scar and healthy tissue are required.