## 4 Discussion
Future efforts should aim to eliminate this phenomenon by investigating the effects of flow, like in the Heartroid simulator, to disrupt the formation of thermal streams during ablation. The overall scores from the questionnaire suggest that both simulators are effective and realistic training systems for CA training. The experimental simulator made effective use of 3D printing and laser cutting to improve and consolidate the methods previously proposed by [PERSON] et al. [13]. The silicone leg block for catheter entry provided a useful and effective layer of realism during catheter manipulation. The two simulators compared in this study performed similarly in the field of catheter entry (\(p\) = 0.5551), with scores of approximately 4. The 3D printed phantoms in the experimental simulator provide radiographic landmarks to trainees. The sedimentation of the contrast powders during printing of the vertebrae caused the resins to exhibit a lower CT number than expected; however, the contrast of the spine was realistic against its surroundings. The vertebral phantoms aimed to recreate the average CT number of the vertebrae; future iterations should render the outlines of the vertebrae more evident by adding a layer of cortical bone. In the Heartroid simulator, the lack of radiopaque phantoms and the presence of metal components obstructing the field of view caused it to significantly underperform during X-ray imaging. The placement of patches inside the saline made the electrical connections in the experimental simulator more reliable and robust than in the Heartroid simulator, which was often subject to contact failures; however, this feature increases the costs of operation. Despite the versatility presented by the laser cut tank, its large volume (48 L) makes the assembly process more laborious and impractical. Conversely, the Heartroid system has a volume of only 6 L, making it more practical to fill and drain with saline. 3D printing was an effective manufacturing modality to replicate the geometry of the heart in both simulators. Both simulators achieved high scores in the field of phantom geometry, showing that they both have satisfactory anatomical realism to fit the needs of atrial CA training. In this field, the difference was statistically insignificant (\(p\) = 0.1709). The Heartroid had excellent geometry, containing the necessary physical landmarks for atrial and ventricular CA, whereas the experimental phantom was only adapted to atrial CA. Physiologists suggested that it may be \"too easy\" to access the left atrium through the transeptal apertures in the Heartroid, while, in the experimental simulator, the transeptal hole was considered \"too stiff\" or \"hard\", making it more difficult to maneuver, especially as the contact response between catheter and model is specific to the model material and the behavior of the catheter within the beating heart is observed to be different. Both of the 3D-printed phantoms could be mapped and ablated with ease; however, the higher number of ablations performed on the Heartroid suggests that it was easier to navigate through the commercial simulator. Comments indicate that this was caused by the stiffness of Layfomm40, which complicated navigation and manipulation through the transeptal hole. The new simulator prototype proposed in this article successfully made use of the concepts previously presented by [PERSON] et al. [13] to create a more realistic and reliable training system. The large tank design enabled users to place the patches in realistic positions away from the fluoroscopy field of view. As reported in the feedback, the addition of the leg phantom and the spine phantom improved the overall realism of the system. The use of the HPI setting, paired with the more realistic electrical environment inside the tank, result in a more predictable ablation outcome compared to the previous simulator prototype.