High-Performance Stimulating Coils and Eddy Currents in Magnetic Heart Stimulation

Effective stimulating coils were developed for magnetic excitation of cardiac muscle, and eddy currents produced by the coils were observed and calculated. The coils were flat solenoids made from beryllium-copper alloy, having a structure at satisfactory mechanical strength. Two coils were effectively combined to intensify stimulus fields in a target heart. The spatial distribution of the eddy current density was measured for a cylindrical volume filled with saline solution which was adopted as a model of the canine body. The result agrees well with the eddy current density calculated by the finite difference method. The performance of the present coil system is discussed from the point of view of magnetic defibrillation.