Abstract 2677: Improved Risk Profile With Preserved Lesion Formation of a Novel Open-Irrigated Ablation Catheter in an Acute Canine Model
Background: During radiofrequency ablation, open-irrigated (OI) tip catheters provide a convective cooling effect that produces larger lesions than non-irrigated tip catheters. However, lesion size and the risk of temperature-related complications may be impacted by different patterns of tip irrigation.
Methods: Therefore, we compared a novel open-irrigated catheter (OI) with a conventional Thermocool catheter (TC) to determine if greater uniformity in irrigation of the catheter tip impacted lesion formation and size, as well as complications. Six healthy dogs underwent percutaneous radiofrequency ablation with both catheters at varying powers (mean atrial 23.8±4.1W, right ventricular 24.3±6.3W, left ventricular 30.7±2.3W) in all cardiac chambers for 60s. Irrigation rates were 17ml/min for ≤25W and 30ml/min for ≥30W.
Results: 104 burns were analyzed. In the atria, tip temperatures were 40.4±4.9°C during TC ablation versus 28.9±7.5 °C during OI ablation (p<0.001). In the ventricles, tip temperatures were 37.5±4.8 °C during TC ablation versus 27.9±1.4 °C during OI ablation (p<0.001). Four atrial ablations using TC catheter (20 –35W) were limited by high tissue temperatures (≥50°C), one of which was associated with a palpable steam pop. In contrast, no atrial ablations using OI catheter were temperature-limited, although one OI ablation was associated with an impedance rise at a tip temperature of 28°C. Real-time thermography of right ventricular epicardial lesion formation (n=13 lesions) demonstrated comparable maximal epicardial tissue temperatures (TC 72.5±27.6°C, OI 80.0±25.0 °C, p=0.62). No significant differences were noted in lesion volumes in the atria (TC 219.6±292.3 mm3, OI 210.2±236.8 mm3) or right ventricle (TC 621.7±698.5 mm3, OI 538.4±582.3 mm3). In the left ventricle, smaller, but not significant lesion volumes were noted with the OI catheter (TC 1333.0±1746.3 mm3, OI 607.6±608.9 mm3, p=0.24).
Conclusion: The novel OI catheter produced less endocardial surface heating than the Thermocool catheter, with comparable epicardial heating and acute lesion formation. The OI catheter may have a safer risk profile, by limiting steam pops thereby reducing tamponade risk, when higher powers are required during atrial ablation.