The first batteryless, solar-powered cardiac pacemaker.
BACKGROUND
Contemporary pacemakers (PMs) are powered by primary batteries with a limited energy-storing capacity. PM replacements because of battery depletion are common and unpleasant and bear the risk of complications. Batteryless PMs that harvest energy inside the body may overcome these limitations.


OBJECTIVE
The goal of this study was to develop a batteryless PM powered by a solar module that converts transcutaneous light into electrical energy.


METHODS
Ex vivo measurements were performed with solar modules placed under pig skin flaps exposed to different irradiation scenarios (direct sunlight, shade outdoors, and indoors). Subsequently, 2 sunlight-powered PMs featuring a 4.6-cm(2) solar module were implanted in vivo in a pig. One prototype, equipped with an energy buffer, was run in darkness for several weeks to simulate a worst-case scenario.


RESULTS
Ex vivo, median output power of the solar module was 1963 μW/cm(2) (interquartile range [IQR] 1940-2107 μW/cm(2)) under direct sunlight exposure outdoors, 206 μW/cm(2) (IQR 194-233 μW/cm(2)) in shade outdoors, and 4 μW/cm(2) (IQR 3.6-4.3 μW/cm(2)) indoors (current PMs use approximately 10-20 μW). Median skin flap thickness was 4.8 mm. In vivo, prolonged SOO pacing was performed even with short irradiation periods. Our PM was able to pace continuously at a rate of 125 bpm (3.7 V at 0.6 ms) for 1½ months in darkness.


CONCLUSIONS
Tomorrow's PMs might be batteryless and powered by sunlight. Because of the good skin penetrance of infrared light, a significant amount of energy can be harvested by a subcutaneous solar module even indoors. The use of an energy buffer allows periods of darkness to be overcome.
Department of Cardiology, Bern University Hospital and University of Bern, Bern, Switzerland; ARTORG Center for Biomedical Engineering, University of Bern, Bern, Switzerland. Electronic address: andreas.haeberlin@insel.ch.
Andreas
A
Haeberlin
ARTORG Center for Biomedical Engineering, University of Bern, Bern, Switzerland.
Adrian
A
Zurbuchen
ARTORG Center for Biomedical Engineering, University of Bern, Bern, Switzerland.
Sébastien
S
Walpen
ARTORG Center for Biomedical Engineering, University of Bern, Bern, Switzerland.
Jakob
J
Schaerer
ARTORG Center for Biomedical Engineering, University of Bern, Bern, Switzerland; Institute for Human Centered Engineering, Bern University of Applied Sciences, Biel, Switzerland.
Thomas
T
Niederhauser
Department of Cardiovascular Surgery, Bern University Hospital and University of Bern, Bern, Switzerland.
Christoph
C
Huber
Department of Cardiology, Bern University Hospital and University of Bern, Bern, Switzerland.
Hildegard
H
Tanner
Department of Cardiology, Bern University Hospital and University of Bern, Bern, Switzerland.
Helge
H
Servatius
Department of Cardiology, Bern University Hospital and University of Bern, Bern, Switzerland.
Jens
J
Seiler
Photovoltaics Laboratory, Bern University of Applied Sciences, Burgdorf, Switzerland.
Heinrich
H
Haeberlin
Department of Cardiology, Bern University Hospital and University of Bern, Bern, Switzerland.
Juerg
J
Fuhrer
ARTORG Center for Biomedical Engineering, University of Bern, Bern, Switzerland; Department of Cardiology, Buergerspital Solothurn, Solothurn, Switzerland.
Rolf
R
Vogel
D000818:Animals; D004867:Equipment Design; D008027:Light; D010138:Pacemaker, Artificial; D019919:Prosthesis Implantation / Q000379:methods; D012993:Solar Energy; D013472:Sunlight; D013552:Swine
Batteryless pacemaker; Batteryless pacing; Energy harvesting; Pacemaker; Pacemaker technology; Solar pacemaker; Sunlight; Sunlight-powered pacemaker