Very-high power short duration radiofrequency ablation (90W/4seconds) under mild conscious sedation: lesion metrics and 12-month outcomes

Abstract

Abstract Background Pulmonary vein isolation (PVI) is often performed under general anaesthesia (GA) or deep sedation. Anaesthetic availability is limited in many centres across Europe, and deep sedation is prohibited in some countries without anaesthetic support. Very high-power short duration (vHPSD – 90W/4sec) PVI using the Q-Dot catheter is well tolerated under mild conscious sedation (MCS) administered by nurses under physician direction. Here, we present lesion metrics and 12-month freedom from atrial arrhythmia with this approach. Methods Our approach to radiofrequency (RF) PVI under MCS is standardised and includes a single catheter approach with a steerable sheath (Figure 1). We identified patients who had undergone Q-Dot RF PVI between March 2021 and December 2022 in our centre, comparing those undergoing vHPSD ablation under MCS (90W/MCS) against those undergoing 50W ablation under GA (50W/GA). Data were extracted from the CARTO system and electronic clinical records. Results 83 patients were included in our analysis (51 90W/MCS; 32 50W/GA). Despite shorter ablation times (353 vs 886 sec; p<0.001), the 90W/MCS group received more lesions (median 87 vs 58, p<0.001), resulting in similar procedure times (120 vs 123 min; p=0.705) (Figure 2). PVI was achieved in all cases, and first pass isolation rates were similar (left WACA 82.4% vs 87.5%, p=0.758; right WACA 74.5% vs 78.1%, p=0.796; 90W/MCS vs 50W/GA respectively). Analysis of 6,647 ablation lesions found similar mean impedance drops (10.0 ± 1.9 Ω vs 10.0 ± 2.2 Ω; p=0.989) and mean contact force (14.6 ± 2.0 g vs 15.1 ± 1.6 g; p=0.248). Similar percentages of lesions achieved >10Ω impedance drop in each arm (48.5 ± 23.1% vs 42.6 ± 17.4%; p=0.224). Only a median 2.5% of lesions in the 90W/MCS arm failed to achieve impedance drop ≥5Ω, compared with 13.7% in the 50W/GA arm (p<0.001). In the 90W/MCS group, there were no procedural related complications. Across median 12-month follow-up, freedom from atrial arrhythmia was observed in 78.4% of patients in the 90W/MCS group, compared with 68.8% in the 50W/GA group (p=0.437), the difference likely being accounted for by the higher prevalence of persistent AF, hypertension and significant left atrial enlargement in the 50W/GA group. Redo ablation was required in 3 (5.9%) of the 90W/MCS group vs 2 (6.2%) of the 50W/GA group (p>0.999) during 12-month follow-up. Conclusion vHPSD PVI can be performed under nurse-administered MCS safely and effectively to achieve adequate rates of 12-month arrhythmia freedom. The mean contact force and impedance drop of a 90W/MCS lesion is similar to a 50W/GA lesion. Whilst more lesions may be required using 90W/MCS to achieve FPI, total ablation duration is significantly shorter and procedural times are similar when compared to 50W/GA. This provides a compelling option for centres with limited anaesthetic support.Figure 1Figure 2