Prediction of implantable ECG lead systems by using thorax models.

New implantable ECG devices may provide more stable and noiseless measurements compared to body surface ECG measurements. When the electrodes are moved to inside of the body the way the ECG measurement is done is changing. Modeling can be an effective way to study effects of implantation to the capacity of electrodes to measure ECG compared to surface measurements. This work introduces a project where effects of electrode implantation to the magnitude and direction of lead sensitivity to detect cardiac source, lead field, was studied with a model of the thorax as a volume conductor. The study was based on 3D finite difference method (FDM) featuring visible human man. The results of the study indicate that the effect of electrode implantation under the skin (5-15 mm) to the way they measure ECG is rather small. Magnitude change is dependent of the studied lead and the change of the sensitivity to heart's equivalent sources in direction of lead field is minor.