Clin Res Cardiol (2023). https://doi.org/10.1007/s00392-023-02302-4

Bioresorbable Molybdenum Electrodes: Towards a Novel Generation of Temporary Epicardial Pacing Wires
M.-E. Prieto Jarabo1, C. Redlich2, A. Schauer1, C. Guder2, G. Pöhle2, T. Weißgärber2, V. Adams1, U. Kappert1, A. El-Armouche3, A. Linke1, M. Wagner1
1Klinik für Innere Medizin und Kardiologie, Herzzentrum Dresden GmbH an der TU Dresden, Dresden; 2Institut für Fertigungstechnik und angewandte Materialforschung, Fraunhofer IFAM, Dresden; 3Institut für Pharmakologie und Toxikologie, Medizinische Fakultät Carl Gustav Carus der TU Dresden, Dresden;

Cardiac pacing with temporary epicardial pacing wires (TEPW) is used to treat rhythm disturbances after cardiac surgery. Wires typically begin to fail around postoperative day four and are extracted. Occasionally, TEPW cannot be mechanically removed, have to stay in the thorax and may rarely cause serious complications like migration and infection. We aim to develop novel, bioresorbable TEPW which will dissolve over time, even if postoperative removal is unsuccessful. We manufactured prototypical braided molybdenum (Mo) leads (16 Mo wires of 40 µM diameter each, length 18 cm for ex-vivo, 7.5 cm for in-vivo experiments) coated with the biodegradable polymers poly(lactide-co-glycolic acid) (PLGA, inner coating) and polycaprolactone (PCL, outer coating) for shaping and electrical insulation. Mo electrodes showed similar pacing and sensing properties as conventional steel electrodes (Osypka) in Langendorff-perfused rat hearts, even with somewhat lower stimulation thresholds. In artificial body fluid at 37°C, the polymer-coated Mo electrodes dissolved at a rate of 1.6 ± 0.3 µg/cm2·d (n=5) compared to uncoated electrodes with 30.3 ± 0.8 µg/cm2·d (n = 4, p < 0.001). Assessing apoptosis and necrosis in human cardiomyocytes and cardiac fibroblasts, we detected no toxicity at Mo concentrations up to 0.52 mM. To test the in vivo properties of Mo TEPW, we sutured them epicardially onto the anterior wall of the heart of female Wistar rats, led them out of the thorax through an intercostal space and placed them in a subcutaneous pocket. Electrophysiological properties were tested directly after implantation, after two weeks and after one month. Mo electrodes showed similar pacing and sensing properties directly upon implantation and after two weeks, with only impedance and slew rate of the sensed R-wave decreasing time-dependently. After one month, all but one pair of Mo electrodes were mechanically broken at their exit from the thorax, the site of the assumedly highest mechanical stress. The conventional steel TEPW we used as control had similar electrical properties directly after implantation, after two weeks and after one month, without signs of broken electrodes. We demonstrate that Mo TEPW can feasibly be used for epicardial pacing in vivo for up to two weeks. These findings represent an important step in the development of innovative, bioresorbable TEPW as a novel and even safer approach to temporary epicardial pacing.


https://dgk.org/kongress_programme/ht2023/aBS150.html