Analysis of Transcutaneous Communication Delays in a Wirelessly Powered Ventricular Assist Device

Abstract

A growing heart failure population necessitates medical interventions beyond which waiting for transplants can provide. Ventricular Assist Devices (VAD) have proven a preliminarily successful bridging therapy until transplantation. Developments have enabled VADs as a destination therapy, potentially avoiding life threatening circumstances while on the transplant waiting list. The percutaneous driveline required to power, control and measure VAD performance threatens life extension premise with infections. Wireless power and data transfer proves a promising solution. To enable its demand flexibility, a feedback loop that can function despite implant environment complications, is required. This research explores the development and analysis of wireless power transfer assistive feedback communications, to reveal feedback loop delays caused by the implant environment and the hardware itself.Numerical estimates and Finite Element Simulations (FES) establish the presence of delay to a Medical Implant Communications Service (MICS) band radiofrequency signal. Experimental measurements, confirm the presence of environmentally inherent delays. Signaled measurements indicate significantly larger systemic delays. Inductive Power Transmission (IPT) simulations indicate adverse effects to the IPT system’s performance from systemic delays applied to the feedback loop. The system is adjusted to counter the effects of the adversary delay. Pre-and post-tuned responses indicate unavoidable effects of systemic delays.