Effect of using foil electrodes to measure transcardiac current fraction during transthoracic defibrillation

This study explores the effect of using foil electrodes to experimentally measure the fraction of current (F/sub c/) that flows through the heart during transthoracic defibrillation. Since the effect of foil electrodes on current redistribution is poorly understood, a mathematical model specially suited for spherical geometries has been developed. It is a form of boundary element method based on Legendre series expansions. Results from the model show that foil electrodes produce a high degree of transcardiac current redistribution which placed in doubt the validity of F/sub c/ values obtained by the use of foil electrodes.<>