How do tissue conductivities impact on forward-calculated ECGs? An efficient prediction based on principal component analysis

Abstract

Potential distributions on the body surface resulting from a given electrical activity of the heart can be simulated by forward calculations. However, variations in tissue conductivities impact decisively on the results.We used Principal Component Analysis (PCA) to identify the effect of an organ's conductivity on the body surface potentials for both atrial and ventricular signals. Signal changes were described by a mean signal and one pre-dominant variation pattern calculated using the first PCA eigenvector. Knowing this eigenvector the body surface potentials corresponding to any conductivity value could be constructed. The original and reconstructed signals showed a good match based on the analysis of the root mean squared error. Using an interpolation technique, surface potentials were reconstructed for conductivity values that were not part of the initial sample. This allowed for efficiently predicting the impact of tissue conductivities on the body surface potentials for a wide range of conductivity values from few sample simulations.