Modeling of cardiac stimulation by externally applied electromagnetic fields

Magnetic Resonance Imaging (MRI) employs magnetic gradient fields that are switched in the kHz frequency range to spatially encode the image. These time-varying magnetic fields induce electric fields (E-fields) in the patient that can become strong enough to interact with excitable tissues. A paramount safety concern is that high E-field amplitudes can stimulate the heart and cause potentially life-threatening arrhythmias [1]. The lack of experimental data on magnetic cardiac stimulation (CS) in humans has required a conservative approach in the definition of safety regulations for MRI gradient coils (e.g. IEC 60601-2-33), which can restrict the usable performance of high-performance systems.