Abstract 2324: Comparison of Gold and Platinum Electrodes for Saline Irrigated Radiofrequency Ablation
Introduction: Compared to platinum, gold has 4 times greater thermal conductivity. We hypothesized that a gold irrigated ablation electrode can provide additional electrode cooling during saline-irrigated radiofrequency (RF) ablation and reduce thrombus. The purpose of this study was to compare a gold ablation electrode (Gold) to a conventional platinum electrode (Plt) for electrode cooling, tissue temperature, lesion size and thrombus during saline irrigated RF ablation using a canine thigh muscle preparation.
Methods: In 7 dogs, the skin over the thigh muscle was incised and raised to form a cradle which was superfused with heparinized blood (ACT >350 sec) at 37°C. A 7F catheter with a 3.5mm Gold or Plt tip electrode with 6 irrigation holes located 1mm from the tip (BIOTRONIK). The ablation electrode was held perpendicular or parallel to the thigh muscle at 10 g contact weight. RF current was delivered for 60 sec at constant power of 30 W (irrigation 17 ml/min, n=50) or 50 W (irrigation 30 ml/min, n=50) in low blood flow (<0.1 m/sec) to favor thrombus. Electrode temperature (ET), interface temperature and tissue temperatures at 3 mm and 7 mm depths were measured. After each ablation, blood was removed to examine thrombus.
Results: Table⇓. Compared to Plt electrode, Gold electrode ablation resulted in similar tissue temperatures and lesion size. However, ET was significantly lower in Gold electrode. Thrombus occurred more frequently with parallel electrode-tissue orientation in both electrodes. Thrombus was usually located at the proximal edge of the ablation electrode. With parallel orientation, Gold was associated with a lower incidence of thrombus at 30 W and the smaller size of thrombus at 50 W.
Conclusions: Compared to Plt, electrode, Gold electrode reduced the incidence (and size) of thrombus during saline irrigated RF ablation. Additional irrigation holes at the proximal edge of the ablation electrode may be required for complete elimination of thrombus.