Radiofrequency Ablation at Low Irrigation Flow Rates Using a Novel 12-Hole Gold Open-Irrigation Catheter

BACKGROUND: High irrigation rates during radiofrequency (RF) ablation may cause fluid overload and limit lesion size. This in vivo animal study assessed the safety and efficacy of RF ablation at low irrigation rates using a novel 12-hole gold catheter. METHODS: A total of 103 lesions, created on the thigh of five mongrel dogs, were analyzed. Lesions were created using a 12-hole irrigated gold-tip (Au) and a six-hole irrigated platinum-iridium (PtIr) catheter (both 7F/3.5-mm electrode; BIOTRONIK SE & CO, KG, Berlin, Germany) in parallel and perpendicular orientation. RF current was delivered for 60 seconds at 30 W using 8 mL/min and 15 mL/min irrigation. Electrode temperature, steam pops, lesion dimensions, and coagulum formation were recorded. RESULTS: Electrode temperatures were lower for Au compared to PtIr in parallel (8 mL/min: 38.1 +/- 1.7 degrees C vs 48.0 +/- 4.8 degrees C, P < 0.0001; 15 mL/min: 36.0 +/- 1.5 degrees C vs 46.9 +/- 5.4 degrees C, P < 0.0001) and perpendicular position (15 mL/min: 35.5 +/- 1.2 degrees C vs 38.4 +/- 2.5 degrees C, P = 0.003). The number of steam pops between Au and PtIr was comparable for parallel (8 mL/min: 14% vs 27%, P = 0.65; 15 mL/min: 14% vs 43%, P = 0.21) and perpendicular orientation (8 mL/min: 25% vs 17%, P = 1.00; 15 mL/min: 18% vs 0%, P = 0.48). Au created larger volumes than PtIr at 8 mL/min irrigation (861 +/- 251 mm3 vs 504 +/- 212 mm3 , P = 0.004); however, for 15 mL/min, volumes were comparable (624 +/- 269 mm3 vs 768 +/- 466 mm3 , P = 0.46). No coagulum formation was observed for any of the catheters on the surface and catheter tip. CONCLUSION: RF ablation at low flow rate using a novel 12-hole irrigation Au catheter is safe and results in larger lesions than with a PtIr electrode