Guidelines for predicting lesion size at common endocardial locations during radio-frequency ablation

We used the finite element method to study the effect of radio-frequency (R F) catheter ablation on tissue heating and lesion formation at different in tracardiac sites exposed to different regional blood velocities. We examine d the effect of application of RF current in temperature- and power-control led mode above and beneath the mitral valve annulus where the regional bloo d velocities are high and low respectively. We found that for temperature-c ontrolled ablation, more power was delivered to maintain the preset tip tem perature at sites of high local blood velocity than at sites of low local b lood velocity This induced more tissue beating and larger lesion volumes th an ablations at low velocity regions. In contrast, for power-controlled abl ation, tissue heating was less at sites of high compared with low local blo od velocity for the same RF power setting, This resulted in smaller lesion volumes at sites of low local velocity, Our numerical analyzes showed that during temperature-controlled ablation a t 60 degreesC, the lesion volumes at sites above and underneath the mitral valve were comparable when the duration of RF current application was 10 s, When the duration of RF application was extended to 60 s and 120 s,lesion volumes were 33.3% and 49.4% larger above the mitral valve than underneath the mitral valve, Also, with temperature- controlled ablation, tip temperat ure settings of 70 degreesC or greater were associated with a risk of tissu e overheating during long ablations at high local blood velocity sites. In power-controlled ablation (20 W), the lesion volume formed underneath the m itral valve was 165.7% larger than the lesion volume above the mitral valve after 10 s of ablation, We summarized the guidelines for energy applicatio n at low and high flow regions.