Energy management of implantable cardioverter-defibrillators using auxiliary power transfer

Implantable cardioverter-defibrillators (ICDs) are among the most frequently used internal battery-powered implantable systems, allowing for the permanent monitoring of heart signals and inducing cardiac shocks in the event of heart arrhythmias. Evidently, a considerable portion of the system's energy is lost when an electric shock occurs, or the system is prepared to induce an electric shock (by charging the battery), shortening the ICD service life. Then, the system should be surgically replaced in a short time. Contrary to the previous works, this study introduces a novel technique to manage and compensate for the internal energy of ICDs and develop complementary energy channels through optimized inductive links. Different inductive drivers are analyzed and compared based on the physical ICD conditions to design an efficient auxiliary inductive wireless energy transfer system. A comparison of wireless power transfer scenarios indicated that power transfer using electromagnetic field induction and coupling coils was optimal. This study also aims to simultaneously enhance the coupling factor and quality factor of the coils by employing geometric optimization in coil width, spacing, and number of turns. The analytical and simulation models were validated, and the experimental results demonstrated a maximum WPT efficiency of 51%, which outperforms similar works reported in recent literature.