Simulation of Body Surface Potentials During Ventricular Pacing

The goal of the study was to simulate body surface potentials (BSP) during ventricular pacing using a realistic homogeneous model of cardiac ventricles and the patient torso. Simulated BSP were compared with BSP measured in a real patient during pacing of the right ventricle. Ventricular activation in the model was started in the known position of the implanted stimulation electrode in the right ventricle near the apex as well as in several other sites near this position. The propagated electrical activation in the ventricular model was modeled using bidomain reaction-diffusion (RD) equations with the ionic transmembrane current density defined by the modified FitzHugh-Nagumo (FHN) equations. The torso was treated as a passive volume conductor region. The whole model was numerically solved in the Comsol Multiphysics environment. The measured BSP were compared with simulated BSP calculated for several positions of the stimulated region. The polarity and shape of selected simulated and measured ECG leads were in the best accordance when the stimulated region was close to the real position of the stimulating electrode. In this case, also the overall distribution of simulated and measured BSP was similar. In the initial phase of ventricular activation, the simulated BSP were strongly dependent on the position of the stimulated region.