GLOBAL ELECTROPHYSIOLOGICAL MAPPING OF THE ATRIUM - COMPUTERIZED 3-DIMENSIONAL MAPPING SYSTEM

The atria are anatomically complex three-dimensional (3-D) structures. Impulse propagation is dynamic and complex during both normal conduct ion and arrhythmia. Atrial activation has traditionally been represent ed on two-dimensional surface maps, which have inherent inaccuracies a nd are difficult to interpret. Interactive, computerized 3-D display f acilitates interpretation of complex atrial activation sequence data o btained from form-fitting multipoint electrodes. Accordingly, the purp ose of this article is to describe the application of 3-D form-fitting electrode molds to the 3-D mapping and display system developed in th is laboratory for the study of complex cardiac arrhythmias. Computer g enerated 3-D surface models are created from a database of serial cros s-sectional anatomical images. Points chosen on endocardial and epicar dial surfaces in each cross-sectional image are processed to create po lygons defining myocardial wall boundaries. The polygons from adjacent serial images are then combined, to create a 3-D surface model. The d iscrete anatomical locations of unit electrodes on multipoint electrod e templates are then assigned in the proper position on the surface mo del. Computer analysis of simultaneous activation data from each unit electrode is performed based on parameters set by the user. Activation data from each unit electrode site are displayed on the computer surf ace model in a color spectrum correlating with a user-defined time sca le. Activation sequence maps can be visualized as static isochrone map s, interval maps, or as dynamic maps at variable speeds, from any 3-D perspective. Thus, an interactive computerized 3-D display system is d escribed, which allows anatomically superior analysis and interpretati on of complex atrial arrhythmias.