Atrial substrate characterization based on bipolar voltage electrograms acquired with multipolar, focal and mini-electrode catheters

Background: Bipolar voltage (BV) electrograms for left atrial (LA) substrate characterization depend on catheter design and electrode configuration.

Aims: The aim of the study was to investigate the relationship between the BV amplitude (BVA) using four catheters with different electrode design and to identify their specific LA cutoffs for scar and healthy tissue.

Methods and results: Consecutive high-resolution electroanatomic mapping was performed using a multipolar-minielectrode Orion catheter (Orion-map), a duo-decapolar 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 3 × 3 × 3 mm3. The equivalent BVA cutoff for every catheter was calculated for established reference cutoff values of 0.1, 0.2, 0.5, 1.0, and 1.5 mV. We 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 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 and 2.21 mV, respectively.

Conclusion: When measuring LA BVA, significant differences were seen between focal, multielectrode, and minielectrode catheters. Adapted cutoffs for scar and healthy tissue are required for different catheters.