Horizontal electrode orientation produced 25-30% smaller lesion volumes than vertical orientation for irrigated radiofrequency ablation catheters, likely due to greater active tissue cooling.
Does horizontal electrode orientation reduce lesion volume compared to vertical orientation during irrigated radiofrequency ablation in isolated porcine myocardium?
Horizontal electrode orientation reduces lesion volumes for irrigated RF catheters compared to vertical orientation, likely due to greater active tissue cooling.
BACKGROUND: Irrigated radiofrequency (RF) ablation catheters may produce different lesion sizes dependent upon the electrode orientation to the tissue. This study examined the effect of irrigated electrode orientation on the lesion size and explores a potential mechanism for this effect. METHODS AND RESULTS: Lesions were created in isolated porcine myocardium using an open irrigation, closed irrigation, and nonirrigated RF catheter (all 3.5-4 mm tips). Lesions were created with the electrodes with all permutations of electrode orientation (vertical or horizontal), contact pressure (6 or 20 g), and saline superfusate flow (0.2 or 0.4 m/sec) over tissue interface. The effect of electrode irrigation without RF delivery on tissue temperature was assessed with intramyocardial temperature probes and infrared thermal imaging. For both irrigated catheters, the horizontal orientation produced 25-30% smaller lesion volumes than the vertical orientation despite equal or greater power deliveries. The horizontal orientation produced larger lesion volumes for the nonirrigated catheter. Higher superfusate flow rates were associated with decreased lesion volumes for the irrigated catheters but greater lesion volumes for the nonirrigated catheter. Catheter irrigation alone without RF delivery reduced intramyocardial temperatures up to 4.9 degrees C and the horizontal orientation produced a 2-fold greater area of tissue cooling than the vertical orientation. CONCLUSION: Horizontal electrode orientations reduce lesion volumes for irrigated RF catheters. This effect may be in part due to greater areas of active tissue cooling in the horizontal orientation.
Wood et al. (Tue,) conducted a other in isolated porcine myocardium. Horizontal electrode orientation vs. Vertical electrode orientation was evaluated on Lesion volume. Horizontal electrode orientation produced 25-30% smaller lesion volumes than vertical orientation for irrigated radiofrequency ablation catheters, likely due to greater active tissue cooling.