Thermal-electrical finite element modelling for radio frequency cardiac ablation: effects of changes in myocardial properties

Finite element (FE) analysis has been utilised as a numerical tool to deter mine the temperature distribution in studies of radio frequency (RF) cardia c ablation. However, none of the previous FE analyses clarified such comput ational aspects as software requirements, computation time or convergence t est. In addition, myocardial properties included in the previous models var y greatly. A process of FE modelling of a system that included blood, myoca rdium, and an ablation catheter with a thermistor embedded at the tip is de scribed. The bio-heat equation is solved to determine the temperature distr ibution in myocardium using a commercial software application (ABAQUS). A C auchy convergence test (epsilon = 0.1 degreesC) was performed and it is con cluded that the optimal number of elements for the proposed system is 24610 . The effects of changes in myocardial properties (+/- 50% electric conduct ivity, + 100%/-50% thermal conductivity, and + 100%/-50% specific heat capa city) in both power-controlled (PCRFA) and temperature-controlled RF ablati on (TCRFA) were studied. Changes in myocardial properties affect the result s of the FE analyses of PCRFA more than those of TCRFA, and the maximum cha nges in lesion volumes were -58.6% (-50% electric conductivity), -60.7% + 1 00% thermal conductivity), and +43.2% (-50% specific heat).