High efficacy single catheter standardized workflow for radiofrequency ablation of atrial fibrillation in the high-power short-duration era

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: Public Institution(s). Main funding source(s): Dr. Valeriano and Dr. Fabbricatore have been supported by a research grant provided by the Cardiopath PhD program (University of Naples Federico II) BACKGROUND: Recent developments in radiofrequency (RF) ablation technologies have improved the efficacy of pulmonary vein isolation (PVI). The combination of the ablation index, lesion tags, and optimized inter-lesion distance (CLOSE protocol) has further reduced the incidence of gaps along the ablation lines. This high acute success rate challenged the use of conventional circular mapping catheters and prompted a single catheter-approach ablation strategy. Modulating the relationship between resistive and conductive heating, high-power short-duration (HPSD) ablation technology can potentially increase lesion-to-lesion consistency. A novel catheter with optimized temperature control and microelectrodes has been recently designed to further improve workflow efficiency. Purpose: This study aimed to assess the efficacy and efficiency of HPSD ablation in a standardized single-catheter workflow for PVI. Methods: Data on consecutive AF ablations performed with HPSD catheter from December 2020 to December 2021 at a single tertiary-care center were prospectively collected. The workflow consisted of a procedure sequence including single transeptal access with a bidirectional steerable sheath, 3D modeling with 3D rotational angiography, assessment of PV potentials with microelectrodes in each vein (figure 1), followed by radiofrequency encircling of the PVs using a high-power setting of 50W in a temperature- and flow-controlled mode with CLOSE-guided protocol. Isolation was validated by reassessing the previously observed PV potentials and by pacing within the lesion set. Results: A total of 73 consecutive AF patients (67% paroxysmal, 33% persistent) were included. All patients received PVI, 15 underwent additional cavotricuspid isthmus ablation and 6 received additional treatments (table 1). Mean procedure time was 68±27 min with minimal fluoroscopy time and dose (3.2±2.1 min; 4.7±3.9 Gycm2). Complications were infrequent with 1 cardiac tamponade and 1 pericarditis. First-pass isolation was achieved in 91% of the circles and validation by microelectrodes successfully identified the residual gaps with 100% of acute procedural success. In a selected cohort of 20 patients with paroxysmal AF undergoing PVI-only procedure performed by an expert operator, the ablation time was 22.8±5.1 min with a skin-to-skin time of 47.3±7.1 min (table 2). The median follow-up duration was 397 days (IQR: 367-462). AT/AF free survival rate was 90% at 12 months. Conclusions: HPSD ablation using a standardized single-catheter workflow improved the procedural efficiency of PVI and resulted in a high rate of first-pass isolation with a low recurrence rate at 12-month follow-up. [Figure: see text] [Figure: see text]