Global electrophysiological mapping of the atrium: Computerized three-dimensional mapping system

The atria are anatomically complex three-dimensional (3-D) structures. Impulse propagation is dynamic and complex during both normal conduction and arrhythmia. Atrial activation has traditionally been represented on two-dimensional surface maps, which have inherent inaccuracies and are difficult to interpret. Interactive, computerized 3-D display facilitates interpretation of complex atrial activation sequence data obtained from form-fitting multipoint electrodes. Accordingly, the purpose 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 this laboratory for the study of complex cardiac arrhythmias. Computer generated 3-D surface models are created from a database of serial cross-sectional anatomical images. Points chosen on endocardial and epicardial surfaces in each cross-sectional image are processed to create polygons defining myocardial wall boundaries. The polygons from adjacent serial images are then combined, to create a 3-D surface model. The discrete anatomical locations of unit electrodes on multipoint electrode templates are then assigned in the proper position on the surface model. 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 surface model in a color spectrum correlating with a user-defined time scale. Activation sequence maps can be visualized as static isochrone maps, interval maps, or as dynamic maps at variable speeds, from any 3-D perspective. Thus, an interactive computerized 3-D display system is described, which allows anatomically superior analysis and interpretation of complex atrial arrhythmias.