Computer modeling of irrigated-tip electrodes during RF cardiac ablation: Comparative analysis between including and excluding the problem of fluid dynamics

Accurate modeling of the thermal performance of irrigated-tip electrodes in endocardial radiofrequency ablation requires solving a triple coupled problem involving simultaneous electrical conduction, heat transfer, and fluid dynamics. We propose an approximate method that avoids the fluid dynamics problem by setting a constant value of temperature in a specific zone of the electrode tip. Our objective was to assess the capacity of the approximate method by comparing its results with those obtained from the accurate method. The results showed that the approximate method failed to predict the lesion surface width, overestimating it by 5 mm for any insertion depth and blood flow rate. Likewise, it drastically overestimated the maximum temperature reached in the blood. However, the approximate method is able to predict lesion depth reasonably well (differences lower than 0.1 mm between both methods) and the maximum temperature reached in the tissue (differences always less than 3°C) throughout the entire ablation time regardless of blood flow rate and electrode insertion depth. In conclusion, the accurate method is the only capable of simulating the real performance of an irrigated electrode-tip surrounded by blood.