title: Noninvasive Imaging of Human Atrial Activation during Atrial Flutter and Normal Rhythm from Body Surface Potential Maps.
abstract: BACKGROUND
  Knowledge of atrial electrophysiological properties is crucial for clinical intervention of atrial arrhythmias and the investigation of the underlying mechanism. This study aims to evaluate the feasibility of a novel noninvasive cardiac electrical imaging technique in imaging bi-atrial activation sequences from body surface potential maps (BSPMs).
  
  
  METHODS
  The study includes 7 subjects, with 3 atrial flutter patients, and 4 healthy subjects with normal atrial activations. The subject-specific heart-torso geometries were obtained from MRI/CT images. The equivalent current densities were reconstructed from 208-channel BSPMs by solving the inverse problem using individual heart-torso geometry models. The activation times were estimated from the time instant corresponding to the highest peak in the time course of the equivalent current densities. To evaluate the performance, a total of 32 cycles of atrial flutter were analyzed. The imaged activation maps obtained from single beats were compared with the average maps and the activation maps measured from CARTO, by using correlation coefficient (CC) and relative error (RE).
  
  
  RESULTS
  The cardiac electrical imaging technique is capable of imaging both focal and reentrant activations. The imaged activation maps for normal atrial activations are consistent with findings from isolated human hearts. Activation maps for isthmus-dependent counterclockwise reentry were reconstructed on three patients with typical atrial flutter. The method was capable of imaging macro counterclockwise reentrant loop in the right atrium and showed inter-atria electrical conduction through coronary sinus. The imaged activation sequences obtained from single beats showed good correlation with both the average activation maps (CC = 0.91±0.03, RE = 0.29±0.05) and the clinical endocardial findings using CARTO (CC = 0.70±0.04, RE = 0.42±0.05).
  
  
  CONCLUSIONS
  The noninvasive cardiac electrical imaging technique is able to reconstruct complex atrial reentrant activations and focal activation patterns in good consistency with clinical electrophysiological mapping. It offers the potential to assist in radio-frequency ablation of atrial arrhythmia and help defining the underlying arrhythmic mechanism.
authors.affiliation: Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota, United States of America.
authors.forename: Zhaoye
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: Department of Cardiology, Ruijin Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Jin
authors.affiliation: Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota, United States of America.
authors.forename: Long
authors.initials: L
authors.lastname: Yu
authors.affiliation: Department of Cardiology, Ruijin Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China.
authors.forename: Liqun
authors.initials: L
authors.lastname: Wu
authors.affiliation: Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota, United States of America.|Institute for Engineering in Medicine, University of Minnesota, Minneapolis, Minnesota, United States of America.
authors.forename: Bin
authors.initials: B
authors.lastname: He
mesh_terms: D000328:Adult; D000368:Aged; D001282:Atrial Flutter / Q000175:diagnosis* / Q000503:physiopathology; D018780:Body Surface Potential Mapping / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D006325:Heart Atria / Q000503:physiopathology*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D008875:Middle Aged