Background: Although accurate modeling of the thermal performance of irrigated-tip\nelectrodes in radiofrequency cardiac ablation requires the solution of a triple coupled\nproblem involving simultaneous electrical conduction, heat transfer, and fluid dynamics,\nin certain cases it is difficult to combine the software with the expertise necessary\nto solve these coupled problems, so that reduced models have to be considered. We\nhere focus on a reduced model which avoids the fluid dynamics problem by setting a\nconstant temperature at the electrode tip. Our aim was to compare the reduced and\nfull models in terms of predicting lesion dimensions and the temperatures reached in\ntissue and blood.\nResults: The results showed that the reduced model overestimates the lesion surface\nwidth by up to 5 mm (i.e. 70%) for any electrode insertion depth and blood flow rate.\nLikewise, it drastically overestimates the maximum blood temperature by more than\n15 �°C in all cases. However, the reduced model is able to predict lesion depth reasonably\nwell (within 0.1 mm of the full model), and also the maximum tissue temperature\n(difference always less than 3 �°C). These results were valid throughout the entire\nablation time (60 s) and regardless of blood flow rate and electrode insertion depth\n(ranging from 0.5 to 1.5 mm).\nConclusions: The findings suggest that the reduced model is not able to predict\neither the lesion surface width or the maximum temperature reached in the blood,\nand so would not be suitable for the study of issues related to blood temperature,\nsuch as the incidence of thrombus formation during ablation. However, it could be\nused to study issues related to maximum tissue temperature, such as the steam pop\nphenomenon.
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