Successful pacing using a batteryless sunlightpowered pacemaker

Abstract

Aims: Today's cardiac pacemakers are powered by batteries with limited energy capacity. As the battery's lifetime ends, the pacemaker needs to be replaced. This surgical re-intervention is costly and bears the risk of complications. Thus, a pacemaker without primary batteries is desirable. The goal of this study was to test whether transcutaneous solar light could power a pacemaker. Methods and results: We used a three-step approach to investigate the feasibility of sunlight-powered cardiac pacing. First, the harvestable power was estimated. Theoretically, a subcutaneously implanted 1 cm2 solar module may harvest ∼2500 μW from sunlight (3 mm implantation depth). Secondly, ex vivo measurements were performed with solar cells placed under pig skin flaps exposed to a solar simulator and real sunlight. Ex vivo measurements under real sunlight resulted in a median output power of 4941 μW/cm2 [interquartile range (IQR) 3767-5598 μW/cm2, median skin flap thickness 3.0 mm (IQR 2.7-3.3 mm)]. The outputpower strongly depended on implantation depth (rSpearman = 20.86, P < 0.001). Finally, a batteryless single-chamber pacemaker powered by a 3.24 cm2 solar module was implanted in vivo in a pig to measure output power and to pace. In vivo measurements showed a median output power of <3500 μW/cm2 (skin flap thickness 2.8-3.84 mm). Successful batteryless VVI pacing using a subcutaneously implanted solar module was performed. Conclusion: Based on our results, we estimate that a few minutes of direct sunlight (irradiating an implanted solar module) allow powering a pacemaker for 24 h using a suitable energy storage. Thus, powering a pacemaker by sunlight is feasible and may be an alternative energy supply for tomorrow's pacemakers. Published on behalf of the European Society of Cardiology. All rights reserved.