Prospective evaluation of a novel catheter equipped with mini electrodes on a 10-mm tip for cavotricuspid isthmus ablation - The efficacy of a mini electrode guided ablation

Abstract Background Clinical utility of large-tip ablation catheters for cavo-tricuspid isthmus (CTI) ablation has been reported, however, it is limited by the impaired near-field electrogram resolution. This study evaluated the efficiency of a novel mini-electrode (ME) equipped 10-mm tip CTI ablation catheter. Methods Thirty-four patients were prospectively enrolled (Group-A). Initially, radiofrequency energy was applied point-by-point guided by ME signals. If it failed, RF applications were applied conventionally guided by tip-ring signals. The data were compared with 32 and 32 patients undergoing CTI ablation using 8-mm tip (Group-B) and 3.5-mm irrigation-tip (Group-C) catheters, respectively. Results The successful CTI block creation rate was significantly higher in Group-A and Group-B than Group-C (32/34[94.1%], 31/32[96.8%], and 25/32[78.1%], p = 0.027). In Group-A, ME guided ablation was successful in 30 patients and subsequent conventional ablation in 2. There was no significant difference between the 3 groups for the total procedure and fluoroscopic times using the initial catheters. However, the total radiofrequency applications (6.9 ± 3.6, 9.9 ± 4.3, and 12.0 ± 7.1, p = 0.001), total radiofrequency time (358 ± 197, 558 ± 248, and 566 ± 265 s, p = 0.001), and radiofrequency time to achieve initial block (222 ± 159, 471 ± 242, and 396 ± 211 s, p < 0.001) were significantly shorter in Group-A than Group-B and Group-C. In Group-A, a maximal ME amplitude attenuation (86 ± 13%, from 0.84 ± 0.53 to 0.08 ± 0.04 mV) was obtained by 19.0 ± 6.5 s mean applications. Maximal tip-ring amplitude attenuation (76 ± 17%, from 0.58 ± 0.29 to 0.12 ± 0.09 mV) was obtained by 22.1 ± 6.2 s mean applications. Conclusions ME guided ablation using a novel ME equipped 10-mm tip ablation catheter was feasible for human CTI ablation, and might reduce inadvertent radiofrequency applications.