Design and implementation of a relay-based switching system for allowing bioimpedance measurements during pulsed-field ablation

Gaitan Conde, Felipe

Design and implementation of a relay-based switching system for allowing bioimpedance measurements during pulsed-field ablation

Citation

Gaitan Conde, F. Design and implementation of a relay-based switching system for allowing bioimpedance measurements during pulsed-field ablation. 2022. handle: http://hdl.handle.net/10230/54583

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Abstract

Catheter ablation can be applied for the treatment of atrial fibrillation. Ablation using thermal energies such as radiofrequency or cryotherapy may result in discontinuous lesions and nontargeted tissue injury. Pulsed-field ablation (PFA) —also referred to irreversible electroporation (IRE)—, a novel ablation modality, uses short high-intensity electric pulses which result in cell death at target tissue by irreversibly permeabilizing the cell membrane. Faster tissue regeneration, tissue specificity and non-thermal damage, are among the bene- fits claimed for PFA, which may result in an improved safety profile during the procedure. It is widely known that the phenomenon of electroporation and the consequent perme- abilization of the cell membrane leads to a change in the electrical properties of the tissue. Consequently, some studies on IRE have assayed the use of impedance measurements to monitor the effect of electroporation —such studies were focused on the use of IRE for tumor eradication—. The switching mechanism between both systems (the high-voltage electroporation system and the small-signal impedance measuring system) plays an impor- tant role in the overall process, since ideally, measurements before, in between, and after the pulses need to be carried out without interruption. The most common approach is the use of electromechanical relays controlled by a master controller software. However, the design and architecture of the circuit is key in the pursuit of a fail-safe system (i.e., a switching system that will prevent damage even if one of its components fails catastroph- ically), since if a high-voltage signal is leaked and reaches the measuring system it could get damaged. The present thesis describes the design, implementation, and assay of a robust switching system based on reed relays capable of rapidly switching between the high voltage pulses needed to electroporate the tissue and the impedance measuring system, useful to quantify the level of the lesion. The relays are under the control of a master software run on a microcontroller board (Arduino).