Bipolar ablation of refractory atrial and ventricular arrhythmias: Importance of temperature values of intracardiac return electrodes

Abstract

Introduction Bipolar radiofrequency catheter ablation (Bi‐RFCA) emerged as an option for treatment of arrhythmias resistant to the conventional approach. Data on safety issues of Bi‐RFCA, including temperature values of intracardiac return electrode (IRE) are lacking. Objective To determine the safety profile of Bi‐RFCA regarding temperature measurements obtained from nonirrigated IRE of different sizes. Methods The study group consisted of consecutive patients after failed conventional RFCA who underwent Bi‐RFCA. Results Out of 1510 RFCA performed in our center, 19 patients underwent Bi‐RFCA due to refractory to previous RFCA ventricular arrhythmias (15 patients) or typical atrial flutter (four patients). Nonirrigated small (4 mm) and large (8 mm) tip catheters were used as IRE in 14 (including three cross‐overs to 8 mm IRE) and five patients, respectively. A total number of 164 bipolar applications were performed (128 for 4 mm and 36 for 8 mm IRE). Maximal temperatures of 4 mm IRE were significantly higher than those of 8 mm IRE (63°C ± 16°C vs 43°C ± 4°C; P = .027). A significant rise of temperature and steam‐pops, preventing further Bi‐RFCA, occurred in seven patients treated with 4 mm IRE. Bi‐RFCA using 4 mm IRE operated at significantly higher impedance values (211 ± 83 vs 143 ± 38; P = .04) and lower power values (mean 20 W ± 6 W vs 32 W ± 7 W, P = .0005; max 29 W ± 9 W vs 39 W ± 10 W, P = .027). Conclusion The use of 8 mm IRE for Bi‐RFCA is associated with lower temperatures of the catheter used as ground and lower incidence of steam‐pops which may suggest a better safety profile than 4 mm IRE. Determination of safety/efficacy balance requires further studies.

Bipolar radiofrequency catheter ablation between the left ventricular endocardium and great cardiac vein for refractory ventricular premature complexes originating from the left ventricular summit

“…A previous study reported that bipolar RFCA using an 8-mm-tip catheter as RE recorded significant lower impedance and lower temperature compared with a 4-mm-tip catheter. 6 This observation was consistent with the previous ex vivo study. 3 This may be related to the current density; the size of the 2 catheters and the distance between them may regulate current density, which produces lesions.…”

“…Moreover, higher impedance is expected in bipolar RFCA than in unipolar RFCA. A previous study reported that bipolar RFCA using an 8‐mm‐tip catheter as RE recorded significant lower impedance and lower temperature compared with a 4‐mm‐tip catheter . This observation was consistent with the previous ex vivo study .…”

“…In addition, impedance and temperature can be monitored only by AEs while they cannot be monitored by REs in the current setting. Futyma P, et al reported the setup of bipolar RFCA which allows temperature monitoring from AEs and REs simultaneously using two RF generators . Technical advancement and further studies are needed to achieve better outcomes and to ensure safety of the procedure.…”

“…AEs and REs simultaneously using two RF generators. 6 Technical advancement and further studies are needed to achieve better outcomes and to ensure safety of the procedure.…”

Editorial to “Bipolar radiofrequency catheter ablation between the left ventricular endocardium and great cardiac vein for refractory ventricular premature complexes originating from the left ventricular summit”

“…However, the safety is most important issue. Because the methodologies of reported bipolar ablation varied depending on the difference in the systems in reported years, standard method should be established for the expansion of this method through the reports in future.…”