## 4 Discussion  
Myocardial electrical conductivity is reported to be 0.06-0.4 S/m [23,24]; therefore, the electrical resistivity derived from this range is 2.5-16.7 \(\Omega\)m. The average resistivity exhibited by myocardium in this study (7.6 \(\pm\) 0.6 \(\Omega\)m) agrees with these literature values, thus validating the methodology. Layfomm40 soaked in 1.35% saline produced the best results, having no statistically significant difference from the control. However, resistivity values of Layfomm40 soaked with saline from 0.9% to 2.5% all fall within the literature range. During the simulations, the Layfomm40 was placed in the tank with saline at lower concentrations, meaning it would lose salinity over time and increase its resistivity. To maintain realistic resistivity for the longest duration, 1.35% saline was therefore the optimal phantom salinity. Future investigations should test the significance of change in phantom resistivity over simulation time. Intermediate impedance, as described by [PERSON] et al. [22], was reliably achieved at 0.25% tank salinity. As higher impedance reduces lesion size [22], intermediate impedance would produce more concise ablation points than low \begin{table}
\begin{tabular}{c c c} \hline \hline
**Settings** & **Experimental Simulator** & **Commercial Simulator** \\ \hline Max. Power & 76 W & 5 W \\ Mean Power & 41 W & 5 W \\ Max. Temperature & 45 \({}^{\circ}\)C & 30 \({}^{\circ}\)C \\ Mean Temperature & 37 \({}^{\circ}\)C & 25 \({}^{\circ}\)C \\ Max. Impedance & 141 \(\Omega\) & 171 \(\Omega\) \\ Mean Impedance & 125 \(\Omega\) & 149 \(\Omega\) \\ Min. Impedance & 109 \(\Omega\) & 134 \(\Omega\) \\ Max. Impedance Dorp & 23 \(\Omega\)/s & 22 \(\Omega\)/s \\ Mean Impedance Drop & 16 \(\Omega\)/s & 6 \(\Omega\)/s \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Electrophysiological ablation outcomes achieved from 15 ablation points performed on the simulators. The experimental simulator was ablated using the HPI settings. The Heartroid simulator was ablated using the HPI settings with the power set to 4 W. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Questionnaire** & **Experimental** & **Commercial** & **Unpaired** \\
**Section** & **Simulator** & **Simulator** & **Multi-Variance** \\  & & & _t-Test_\(p\) **Value** \\ \hline Cather Entry & 3.90 \(\pm\) 0.88 & 4.13 \(\pm\) 1.06 & 0.5551 \\ Phantom Geometry & 4.11 \(\pm\) 0.93 & 3.33 \(\pm\) 1.56 & 0.1709 \\ X-ray Visibility & 3.66 \(\pm\) 1.30 & 1.55 \(\pm\) 1.22 & 0.0001 \\ Mapping and Ablation & 3.41 \(\pm\) 1.01 & 3.25 \(\pm\) 1.54 & 0.5864 \\ OVERALL SCORE & 3.65 \(\pm\) 1.05 & 3.00 \(\pm\) 1.64 & 0.0033 \\ Number of Ablations & 27 \(\pm\) 16 & 57 \(\pm\) 42 & 0.2621 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Performance of the experimental simulator compared to the commercial state-of-the-art system. impedance, allowing users to gauge lesion size and deduce the original position of the catheter. Consequently, 0.25% saline was chosen to fill the tank during RCA experiments involving Layfomm40 phantoms. Experimental data show that ablation lesions created on the lateral and posterior walls were smaller (1-15 mm\({}^{2}\)) than ablation lesions generated on the anterior wall (50-120 mm\({}^{2}\)). The streaking shape of the ablation lesions suggests that this change may be caused by the thermal movement of water during ablation, resulting from the lack of flow in the system. As the water around the catheter heats up, it decreases in density and travels upwards, collecting on the top (anterior walls). Irrigation in the catheter controls temperature, resulting in smaller lesions on the anterior wall. The HPI settings produced the best results, resulting in larger lesions on the posterior and lateral walls, but smaller lesions on the anterior wall. Additionally, the streaked shape of the HPI lesions still allows the user to track the original catheter location. Though these settings produced more precise results, the shape was still affected by the movement of hot water.