title: Electrodynamic heart model construction and ECG simulation.
abstract: OBJECTIVE
  In this paper, we present a unified electrodynamic heart model that permits simulations of the body surface potentials generated by the heart in motion. The inclusion of motion in the heart model significantly improves the accuracy of the simulated body surface potentials and therefore also the 12-lead ECG.
  
  
  METHODS
  The key step is to construct an electromechanical heart model. The cardiac excitation propagation is simulated by an electrical heart model, and the resulting cardiac active forces are used to calculate the ventricular wall motion based on a mechanical model. The source-field point relative position changes during heart systole and diastole. These can be obtained, and then used to calculate body surface ECG based on the electrical heart-torso model.
  
  
  RESULTS
  An electromechanical biventricular heart model is constructed and a standard 12-lead ECG is simulated. Compared with a simulated ECG based on the static electrical heart model, the simulated ECG based on the dynamic heart model is more accordant with a clinically recorded ECG, especially for the ST segment and T wave of a V1-V6 lead ECG. For slight-degree myocardial ischemia ECG simulation, the ST segment and T wave changes can be observed from the simulated ECG based on a dynamic heart model, while the ST segment and T wave of simulated ECG based on a static heart model is almost unchanged when compared with a normal ECG.
  
  
  CONCLUSIONS
  This study confirms the importance of the mechanical factor in the ECG simulation. The dynamic heart model could provide more accurate ECG simulation, especially for myocardial ischemia or infarction simulation, since the main ECG changes occur at the ST segment and T wave, which correspond with cardiac systole and diastole phases.
authors.affiliation: Department of Biomedical Engineering, Zhejiang University, Hangzhou 310027, China. xialing@zju.edu.cn
authors.forename: L
authors.initials: L
authors.lastname: Xia
authors.forename: M
authors.initials: M
authors.lastname: Huo
authors.forename: Q
authors.initials: Q
authors.lastname: Wei
authors.forename: F
authors.initials: F
authors.lastname: Liu
authors.forename: S
authors.initials: S
authors.lastname: Crozier
mesh_terms: D004562:Electrocardiography; D020342:Finite Element Analysis; D006321:Heart / Q000502:physiology*; D006801:Humans; D008953:Models, Anatomic; D017202:Myocardial Ischemia / Q000503:physiopathology