Quantitative Analysis of Electro-Anatomical Maps: Application to anExperimental Model of Left Bundle Branch Block/Cardiac ResynchronizationTherapy

摘要

Electro-anatomical maps (EAMs) are commonly acquired in clinical routine for guiding ablation therapies. They provide voltage and activation time information on a 3-D anatomical mesh representation, making them useful for analyzing the electrical activation patterns in specific pathologies. However, the variability between the different acquisitions and anatomies hampers the comparison between different maps. This paper presents two contributions for the analysis of electrical patterns in EAM data from biventricular surfaces of cardiac chambers. The first contribution is an integrated automatic 2-D disk representation (2-D bull’s eye plot) of the left ventricle (LV) and right ventricle (RV) obtained with a quasi-conformal mapping from the 3-D EAM meshes, that allows an analysis of cardiac resynchronization therapy (CRT) lead positioning, interpretation of global (total activation time), and local indices (local activation time (LAT), surrogates of conduction velocity, inter-ventricular, and transmural delays) that characterize changes in the electrical activation pattern. The second contribution is a set of indices derived from the electrical activation: speed maps, computed from LAT values, to study the electrical wave propagation, and histograms of isochrones to analyze regional electrical heterogeneities in the ventricles. We have applied the proposed methods to look forthe underlying physiological mechanisms of left bundle branch block (LBBB) and CRT,with the goal of optimizing the therapy by improving CRT response. To betterillustrate the benefits of the proposed tools, we created a set of syntheticallygenerated and fully controlled activation patterns, where the proposed representationand indices were validated. Then, the proposed analysis tools are used to analyze EAMdata from an experimental swine model of induced LBBB with an implanted CRT device.We have analyzed and compared the electrical activation patterns at baseline, LBBB,and CRT stages in four animals: two without any structural disease and two with aninduced infarction. By relating the CRT lead location with electrical dyssynchrony,we evaluated current hypotheses about lead placement in CRT and showed that optimalpacing sites should target the RV lead close to the apex and the LV one distant fromit.