title: Noninvasive electrocardiographic imaging (ECGI): application of the generalized minimal residual (GMRes) method.
abstract: Electrocardiographic imaging (ECGI) is a developing imaging modality for cardiac electrophysiology and arrhythmias. It reconstructs epicardial potentials, electrograms, and isochrones from electrocardiographic body-surface potentials noninvasively. Current ECGI methodology employs Tikhonov regularization, which imposes constraints on the reconstructed potentials or their derivatives. This approach can sometimes reduce spatial resolution by smoothing the solution. Accuracy depends on a priori knowledge of solution characteristics and determination of an optimal regularization parameter. These properties led us to implement an independent, iterative approach for ECGI--the generalized minimal residual (GMRes) method--which does not apply constraints. GMRes was applied to experimental data during activation/repolarization of normal and infarcted hearts. GMRes reconstructions were compared to Tikhonov reconstructions and to measured "gold standards" in isolated hearts. Overall, the accuracy of GMRes solutions was similar to Tikhonov regularization. However, in certain cases GMRes recovered localized potential features (e.g., multiple potential minima), which were lost in the Tikhonov solution. Simultaneous use of these two complementary methods in clinical ECGI will ensure reliability and maximal extraction of diagnostic information in the absence of a priori information about a patient's condition.
authors.affiliation: Cardiac Bioelectricity Research and Training Center, Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106-7207, USA.
authors.forename: Charulatha
authors.initials: C
authors.lastname: Ramanathan
authors.forename: Ping
authors.initials: P
authors.lastname: Jia
authors.forename: Raja
authors.initials: R
authors.lastname: Ghanem
authors.forename: Daniela
authors.initials: D
authors.lastname: Calvetti
authors.forename: Yoram
authors.initials: Y
authors.lastname: Rudy
mesh_terms: D000200:Action Potentials; D000465:Algorithms; D000818:Animals; D018780:Body Surface Potential Mapping / Q000379:methods*; D002304:Cardiac Pacing, Artificial / Q000379:methods; D003198:Computer Simulation; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D004285:Dogs; D004562:Electrocardiography / Q000379:methods; D006329:Heart Conduction System / Q000503:physiopathology*; D008955:Models, Cardiovascular; D008959:Models, Neurological; D009203:Myocardial Infarction / Q000175:diagnosis / Q000503:physiopathology*; D010496:Pericardium / Q000294:innervation / Q000503:physiopathology*; D017180:Tachycardia, Ventricular / Q000175:diagnosis / Q000503:physiopathology*