Ventricular surface. See the following three figures for detailed description.

Ventricular surface represented by a triangulated mesh. Nodes of the mesh formed locations of electrodes mounted on a nylon sock, which was used to conduct cardiac potential recording. RV = right ventricle; LV = left ventricle; LAD = left anterior descending coronary artery; and RCA = right coronary artery.

Multi-electrode needle configuration. In this in situ experiment, electric potentials were measured from 56 plunge needles inserted in the free wall of the left ventricle. Each needle contained 12 electrodes separated by 1.6 mm between each other.

Simulated excitation times in a slab of tissue. Stimulation was applied in the center of the myocardium, which has anisotropic tissue property. An idealized Purkinje network at the endocardium was activated at around 25 ms after the pacing.

Electrical potentials on the epicardial surface during a ventricular stimulation. Here potentials are drawn as a height field. The "fault" demonstrates the large potential gradients associated with the excitation wave in the space. The lower panel shows a sample electrogram at one of the electrode. The red bar indicates the time instance of the potential map.

Comparison of linear and wave-equation based (WEB) interpolations of electric potentials on the epicardial surface. Upper row contains isopotential maps all derived from original recordings from 16X electrodes with 1.5 mm spacing (leftmost panel), interpolated results from a 4X sub-sampling grid (marked by large dots) using the WEB interpolation (center panel), and using standard linear interpolation (rightmost panel). The time instant selected was 13 ms after pacing, as marked by vertical line in the single time signal shown in the bottom left hand panel, which was located at the site marked by the red circle in the left hand map.