Background: Radiofrequency (RF) ablation with high power delivery over short duration (high-power-short-duration; HPSD) is supposed to create efficient lesions with high success rates. Though convincing results exist, it is still under debate whether HPSD will increase risk of complications as steam pops and pericardial effusion. We investigated real-time local-impedance-(LI)-guidance during HPSD-ablation with respect to procedural and safety outcome in order to keep RF-delivery as short as possible while still creating efficient lesions.

Methods: LI-guided pulmonary vein isolation (PVI) and cavotricuspid isthmus ablation (CTI) was performed in all cases, aiming for a minimum LI-drop of 10Ω (for efficacy) and a maximum of 35Ω (for safety). Procedural and safety outcome were evaluated in HSPD vs. conventional(c)-RF-ablation.

Results: 22 patients underwent PVI (12 cRF, 10 HPSD), 18 patients underwent CTI (5 cRF, 13 HPSD). Invasive procedure duration did not differ between HPSD-PVI vs. cRF-PVI, while it was significantly shorter in HPSD-CTI vs. cRF-CTI (19±25 vs. 46±27min; p<0.05) (figure 1a). Cumulative RF-duration was significantly shorter in HPSD-PVI than in cRF-PVI (1552±830 vs. 2730±919sec; p<0.01). In CTI there was only a trend to shorter cumulative RF-duration in HSPD (figure 1b). Required RF-duration/application for achieving a sufficient LI-drop was shorter in HPSD-PVI compared to cRF-PVI (18.5±2.8 vs. 70.0±47.7sec; p<0.001). However, in CTI procedures no difference between RF-duration/application for achieving a sufficient LI-drop (∆11.9±8.4Ω in HPSD, ∆11.3±9.8Ω in cRF) could be shown (figure 1c). Complication rates were very low and did not differ between both groups.

Conclusion: We were able to show that LI-guided HPSD-ablation for PVI or CTI with an anticipated LI-drop of ∆10-35Ω can reduce invasive procedure duration and cumulative RF-duration compared to cRF-ablation with ensuring efficient lesion formation by LI-guidance and without resulting in higher complication-rates.