Noninvasive assessment of cardiac electrophysiology for predicting arrhythmogenic risk: are we getting closer?

Identification of patients at significant risk of arrhythmia and sudden cardiac death is one of today’s major cardiology challenges. Although tremendous progress has been made in detecting and characterizing cardiac disease and its progression, largely through imaging modalities, progress in detecting and monitoring changes in arrhythmogenic states has been incremental and has not resulted in robust, reliable methods of assessment. In this issue of Circulation, Ghosh et al1 demonstrate the application of an evolving technology, electrocardiographic imaging (ECGI), for noninvasive assessment of cardiac electrophysiology. They provide convincing data documenting the success of the method for localizing preexcitation (accessory) pathways in Wolff-ParkinsonWhite patients as well as for assessing short-term remodeling of ventricular repolarization after pathway ablation. The method requires detailed, high-resolution 3-dimensional computed tomographic imaging of the patient’s torso, body surface potential mapping of the torso with the use of hundreds of leads during any rhythms and conditions of interest, and mathematical modeling of the 3-dimensional electric fields to yield “inverse” estimates of epicardial potential distributions and electrograms. Once the 1-time anatomic imaging and modeling are completed (presumed constant for each patient), the body surface potential mapping recorded during any rhythm or cardiac condition can be transformed to the level of the epicardium to visualize epicardial isopotential map sequences, electrograms, and consequently activation and repolarization sequences.