Effect of Skin Electrode Location on Radiofrequency Ablation Lesions: An In Vivo and a Three‐Dimensional Finite Element Study

OBJECTIVES: To assess the effect of skin electrode location on radiofrequency (RF) ablation lesion dimensions and energy requirements. BACKGROUND: Little is known about the effects of skin electrode location on RF ablation lesion dimensions and efficiency. METHODS AND RESULTS: Temperature-controlled ablation at 60 degrees C for 60 seconds was performed in six sheep. Paired lesions were created in the lateral, anterior, posterior, and septal walls of both the ventricles. For group 1 lesions, the skin electrode was positioned directly opposite the catheter tip (optimal). For group 2 lesions, we used either the standard posterior location or an anterior location if the posterior skin electrode location was used for group 1. Group 1 lesions were 5.8+/-0.8 mm deep and 9.3+/-1.9 mm wide, compared with 4.6+/-1.0 mm deep and 7.7+/-1.9 mm wide group 2 lesions (P or = 90 degrees C was 0.005 mm3 for optimal versus 2.2 mm3 for the nonoptimal location. CONCLUSION: Optimal skin electrode placement: (1) creates deeper and larger lesions; (2) reduces lesion size variability; and (3) decreases blood heating.