Background: Radiofrequency(RF) ablation of premature ventricular complexes(PVCs) is a well-established treatment for patients high PVCs burden, even when arising from epicardial/intramural localization. Consistent data about safety of using high power RF is lacking in literature in these regions. Aim: The aim of this study is to investigate safety of different RF power settings, efficacy and outcome of non-endocardial PVCs ablation. Methods: Consecutive patients who underwent PVC ablation were included (2017-2023). We defined “Non-Endocardial Radiofrequency Ablation”(NERA) a procedure in which at least one ablation site has been identified into the cardiac venous system, aortic cusps, inter-leaflet region or pulmonary cusps. Results: Total number of NERA sites was 64 in 53 procedures. In 63% of the procedures, high power (≥40W) and in 60% long duration (≥60 seconds) RF was delivered in at least one site (mean power:37±9W(15-50), mean duration of single RF 88±65 seconds (30-304)). In 21% of the procedures, a combination of both high power and long duration RF applications was performed. Procedural success was achieved in 47 procedures(84%). Only one severe complication (pericardial bleeding) was observed. In 22(39%) procedures, multisite ablation was performed which was associated with procedural failure (OR 7,47;p=0,01). During follow-up, mean and median PVC burden reduction were 69±41% and 96% respectively. Multisite ablation and coronary venous system RF were predictors of recurrence (HR 3.6;p=0.026 and HR 3.85;p=0.014). Conclusion: Ablation from non-endocardial sites is a safe and effective procedure, even using high power and/or long duration RF with clear benefit in terms of PVC burden reduction.

Till Althoff

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Kurose et al. report on a lower number of gaps in RF-lesions compared to Cryo-lesions as determined by late gadolinium enhancement MRI (LGE-MRI). However, unlike claimed by the authors, there is ample evidence based on LGE-MRI in this context. Most importantly we have specifically compared RF and Cryo lesions in a recent case control study on AF Ablation. In contrast to the results of Kurose et al., our study, despite larger sample size, did not detect a difference in the number of gaps between the two energy sources. While numerous factors may account for the conflicting results, two points should be considered in particular. 1. The time point of LGE-MRI at a mean of 55 days post ablation has never been validated for chronic lesion formation, and is considerably earlier than the validated and well-established 3-months timepoint chosen by most groups. In fact, according to previous reports, gadolinium enhancement at earlier time points may, at least in part, reflect a transient inflammatory response rather than chronic scar formation. 2. The method of Kurose et al. is based on the definition of an area of healthy atrial tissue in each patient as an internal reference. However, it appears almost impossible to define a truly healthy area in the atrium of patients with atrial fibrillation. Thus the method is likely to underestimate ablation-induced fibrosis in patients with advanced disease and/or underlying pathologies and to overestimate it in younger, rather healthy patients.