Feasibility of rapid linear-endocardial and epicardial ventricular ablation using an irrigated multipolar radiofrequency ablation catheter

Background - A common strategy for ablation of scar-based ventricular tachycardia is delivering multiple lesions in a linear pattern. Methods and Results - We tested the efficacy of a novel linear irrigated multipolar ablation catheter capable of creating linear lesions with a single application. Healthy swine underwent endocardial and epicardial linear ablation using a novel linear irrigated ablation catheter; control animals underwent focal lesions in a linear pattern over 3.5 cm with an irrigated radiofrequency catheter. The linear catheter contained 7 irrigated electrodes spaced over 3.5 cm and could deliver ≤25 W to each electrode. Linear ablation required significantly less radiofrequency time than focal ablation (56±11 versus 497±110 seconds; P<0.0001). At gross pathology, linear (n=18) epicardial lines were longer than focal (n=8) epicardial lines (3.3±0.7 versus 2.1±0.9 cm; P<0.0005), with greater volume (3.8±2.9 versus 1.5±1.6 cm³; P=0.002). There was no difference between linear (n=22) and focal (n=7) endocardial line length or volume. Gaps (length 2.8±0.9 mm) were present in 53% of focal lines and 0% of linear ablation lines. No perforations, steam pops, or thrombus were noted. Conclusions - Compared with sequential focal radiofrequency ablation in a linear pattern, an irrigated multipolar linear ablation catheter safely delivers contiguous endocardial or epicardial lesions without gaps in a single ablation. This catheter shows promise for decreasing ventricular tachycardia ablation procedure time and improving outcome.