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

BackgroundHigh 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. MethodsA 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 8mL/min and 15mL/min irrigation. Electrode temperature, steam pops, lesion dimensions, and coagulum formation were recorded. ResultsElectrode temperatures were lower for Au compared to PtIr in parallel (8mL/min: 38.1 1.7 degrees C vs 48.0 +/- 4.8 degrees C, P < 0.0001; 15mL/min: 36.0 +/- 1.5 degrees C vs 46.9 +/- 5.4 degrees C, P < 0.0001) and perpendicular position (15mL/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 (8mL/min: 14% vs 27%, P= 0.65; 15mL/min: 14% vs 43%, P= 0.21) and perpendicular orientation (8mL/min: 25% vs 17%, P= 1.00; 15mL/min: 18% vs 0%, P= 0.48). Au created larger volumes than PtIr at 8mL/min irrigation (861 +/- 251mm(3) vs 504 +/- 212mm(3), P= 0.004); however, for 15mL/min, volumes were comparable (624 +/- 269mm(3) vs 768 +/- 466mm(3), P= 0.46). No coagulum formation was observed for any of the catheters on the surface and catheter tip. ConclusionRF 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.