Introduction: Very high power, short duration ablation (Vhpsd) involves using radiofrequency (RF) ablation powers of 90 W for just 4 seconds per lesion, delivered using the Q-DOT ablation catheter (Biosense Webster). We have shown how shorter ablation lesions improve patient comfort during pulmonary vein isolation (PVI) and may obviate the need for general anaesthesia. It is less clear how the lesion integrity and longer-term efficacy of this approach compares to high power, short duration (HPSD; 50W) ablation. In this analysis, we contrast a cohort of patients undergoing Vhpsd PVI under mild conscious sedation (MCS) against a contemporaneous cohort of similar number who underwent conventional HPSD ablation.
Methods: We retrospectively identified all patients who underwent RF PVI at our institution between March 2021 (release of the Q-DOT catheter) to December 2022 (to give a minimum of 6-month follow-up). Our exclusion criteria included: 1) non-Q-DOT catheter ablation, 2) all redo ablations, 3) PVI with additional left atrial ablation, 4) cases lacking follow-up, 5) Q-DOT hybrid 90/50 W ablations, and 6) Vhpsd under GA. Demographics, procedural characteristics, lesion data and follow-up outcomes were evaluated.
Results: We identified 48 patients who underwent Vhpsd PVI under MCS, and 38 patients who underwent exclusively 50 W Q-DOT HPSD PVI (58% under general anaesthesia). There were no statistically significant differences between the groups in terms of demographics, AF type, and CHA2DS2Vasc score.
A total of 6,701 ablation lesions were analysed. Vhpsd lesions achieved similar mean contact force, stability and impedance drop as HPSD. However, first-pass isolation rates were lower with Vhpsd (58% versus 74%; p=0.144), requiring a greater number of ablation lesions per patient (82.8 ± 22.6 versus 63.4 ± 13.1; p<0.001). Given the shorter individual lesion delivery between the two approaches, the total ablation duration was shorter (329.7 ± 90.6 sec versus 917.3 ± 211.8 sec <0.001), resulting in equivalent procedural times (117 mins versus 114 mins; p=0.615).
Follow-up duration was longer in the Vhpsd group (12 months versus 8.4 months; p=0.008). We applied a 2-month post-ablation blanking period. Recurrence rates of any sustained atrial arrhythmia at follow-up were similar between groups (22.9% versus 28.9%; p=0.525).
Conclusion: Vhpsd ablation (90W–4sec) under mild conscious sedation using the Q-DOT catheter is a viable alternative to conventional 50 W ablation that can require a general anaesthetic to tolerate longer lesions (8–15 sec). Although Vhpsd under MCS incurs lower first pass PV isolation rates requiring more lesions, the overall procedural times remain similar, as are arrhythmia recurrence rates at around 12 months. Vhpsd should be considered an alternative approach to RF PVI when the availability of general anaesthesia is limited. ❑
