EGMs vs LI in non fully transmural scar configurations
Regions with pathologically altered substrate have been identified as potentially responsible for atrial fibrillation (AFib) and atrial flutter (AFlut) maintenance. However, these areas are not well characterized using magnetic resonance imaging or low voltage maps as they entail drawbacks when concluding on the underlying substrate. Local impedance (LI) measurements have recently gained attention in radiofrequency ablation and substrate characterization because changes in conductivity may indicate alterations in myocardial electrophysiology. LI values are expected to distinguish between healthy and scar tissue independently from the atrial rhythm, which can improve the understanding of underlying substrate. Moreover, based on impedance reconstruction simulations performed at our institute, non fully transmural patterns are able to be detected when a certain scar thickness is considered. Up to our knowledge, using voltage to characterize the atrial substrate by means of electrograms does not account for non full transmurality. To prove this can give more insights towards the use of LI measurements when accounting for scar detection at ablation procedures.