Intracardiac Turbines Suitable for Catheter-Based Implantation—An Approach to Power Battery and Leadless Cardiac Pacemakers?

Abstract

Objective: Cardiac pacemakers are powered by batteries, which become exhausted after a few years. This is a problem in particular for leadless pacemakers as they are difficult to explant. Thus, autonomous devices powered by energy harvesters are desired. Methods: We developed an energy harvester for endocardial implantation. The device contains a microgenerator to convert a flexible turbine runner's rotation into electrical energy. The turbine runner is driven by the intracardiac blood flow; a magnetic coupling allows hermetical sealing. The energy harvester has a volume of 0.34 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> and a weight of 1.3 g. Computational simulations were performed to assess the hemodynamic impact of the implant. The device was studied on a mock circulation and an in vivo trial was performed in a domestic pig. Results: In this article, we show that an energy harvester with a 2-bladed 14-mm-diameter turbine runner delivers 10.2 ± 4.8 μW under realistic conditions (heart rate 80/min, stroke volume 75 ml) on the bench. An increased output power (>80 μW) and power density (237.1 μW/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> ) can be achieved by higher stroke volumes, increased heart rates, or larger turbine runners. The device was successfully implanted in vivo. Conclusion: The device is the first flow-based energy harvester suitable for catheter-based implantation and provides enough energy to power a leadless pacemaker. Significance: The high power density, the small volume, and the flexible turbine runner blades facilitate the integration of the energy harvester in a pacemaker. This would allow overcoming the need for batteries in leadless pacemakers.