K. Naib. Development of a novel multielectrode array using microsystem technology for measurements of extracellular potentials in rat myocardium. Institute of Biomedical Engineering, Karlsruhe Institute of Technology (KIT). Masterarbeit. 2016
Cardiac arrhythmias are an increasing health care issue, especially in developed countries. Currently, the most prevalent treatment is radio frequency ablation. With however, the most common significantly detrimental arrhythmia, atrial fibrillation, having a recurrence rate of about 20 % at the 18-month mark, a deeper understanding of ablation lesion physiology is necessary to improve the radio frequency ablation procedure.An in vitro set-up is used to investigate electrophysiological behaviour before and directly after the creation of an ablation lesion on vital rat myocardium. A sensor is required to acquire electrical signals needed to compute intracardiac electrograms. A multielectrode design with eight measuring sites serves as a basis for the sensor. This multielectrode array has to integrate into the existing in vitro set-up and avoid adversely affecting the cardiac tissue sample.A morphological analysis is used to create multiple concepts by breaking down the design task into constituent subfunctions. These concepts are assessed, reworked, and then turned into a final design for construction. Using a casting process in specialised moulds, a flexible, durable, and biocompatible multielectrode array is manufactured from polydimethylsiloxane and silver. Roadblocks encountered in insulating individual silver wires, to prevent electrical shorts, are circumvented by improving the manufacturing process. Finished multielectrode array prototypes undergo various electrical tests, including a vital tissue test, to investigate their function.With a satisfactory design accuracy, the prototypes manage to perform electrophysiological signal acquisition as intended. Further research using the multielectrode array in the in vitro set-up, aims to further understanding in the underlying mechanisms of cardiac tissue ablation.