Pulsed Transmission Waveform to Mitigate Tissue Thermal Effects in Transcutaneous Wireless Energy Supply Systems for High-Power Rated Medical Implants

Abstract

Therapeutic options in end stage heart failure include cardiac transplantation or mechanical circulatory support: Left Ventricular Assist Device (LVAD) or Total Artificial Heart (TAH). These devices have relatively high power requirements (5–80 W). Existing power supplies to LVAD and TAH are via percutaneous drivelines with a high frequency of complications including infection. We have developed a wireless Transcutaneous Energy Transmission (TET) waveform protocol and system technology which address the major clinical drawbacks of existing systems: skin tissue thermal effect and system durability. Conventional single-channel TET solutions have significant limitations, including inefficient energy transfer characteristics and high energy density levels producing tissue thermal effects. A reduced lifetime of the internal rechargeable battery is an additional drawback. In the proposed novel system, a multi-channel, time-space multiplexed and pulsed RF transmission waveform transcutaneous power delivery approach, is presented for sustained internal energy supply to high-power rated implantable devices. The bench system prototype performance evaluation results, revealed excellent high-energy transfer efficiency and safer management of lower energy density levels. In conclusion, the proposed pulsed transmission waveform protocol and multi-channel concepts can be configured for individual high-power rated LVAD devices to effectively mitigate tissue thermal effects and to prolong backup battery lifetime.