Aim of the presented experimental and theoretical model was to characterize the power deposition process in cardiac catheter ablation. A dedicated set-up, based on a transparent temperature-sensitive gel-phantom was developed. A liquid crystal film was used to map the temperature distribution during RF deposition. An infrared acquiring system and a postprocessing image software were used to define the heating zone and to quantify the device specific heating fingerprint. Experimental results were compared to a thermal conduction model with spherical symmetry, showing good agreement for ablation time 100 < t < 600 s. Differences between model and experimental results were explained by deviation of the real heating pattern from spherical geometry.