Evaluation of the Feasibility of Three Custom-made Tetrapolar Probes for Electrical Characterization of Cardiac Tissue

Non-thermal cardiac ablation can be used to treat atrial fibrillation and consists in applying a pattern of electrical pulses to the targeted tissue. Knowing the conductivity of the tissue gives an extent of the pulse parameters needed for the ablation. However, there is a lack of conductivity data for cardiac tissues in the range of frequencies of non-thermal ablation. To this extent, this paper presents a feasibility study for the use of three tetrapolar probes, a planar probe, a needle probe and a pin probe, for cardiac tissue electrical characterization. Probe performance was evaluated across the range of 0.1-100 kHz. The planar probe was the most accurate in reference liquid measurements. Thus, it was used to characterize ovine ex vivo cardiac tissue, which measured conductivity is lower than that from the literature. These results suggest the need for a probe design optimization to improve the contact with the tissue.