Contact force (CF)–sensing radiofrequency (RF) catheters with an ablation index have shown reproducible outcomes for the treatment of atrial fibrillation (AF) in large multicentre studies. A dual-energy (DE) focal CF catheter to deliver RF and unipolar/biphasic pulsed field ablation (PFA), integrated with a three-dimensional (3D) mapping system, can provide operators with additional flexibility. The SmartfIRE study assessed the safety and efficacy of this novel technology for the treatment of drug-refractory, symptomatic paroxysmal AF. Results at 3 months post-ablation are presented here. Pulmonary vein isolation (PVI) was performed using a DE focal, irrigated CF-sensing catheter with the recommendation of PFA at posterior/inferior and RF ablation at the anterior/ridge/carina segments. Irrespective of energy, a tag size of 3 mm; an inter-tag distance ≤6 mm; a target index of 550 for anterior, roof, ridge, and carina; and a target index of 400 for posterior and inferior were recommended. Cavotricuspid isthmus ablation was permitted in patients with documented typical atrial flutter. The primary effectiveness endpoint was acute procedural success. The primary safety endpoint was the rate of primary adverse events (PAEs) within 7 days of the procedure. A prespecified patient subset underwent oesophageal endoscopy (EE; 72 h post-procedure), neurological assessment (NA; pre-procedure and discharge), and cardiac computed tomography (CT)/magnetic resonance angiogram (MRA) imaging (pre-procedure and 3 months post-procedure) for additional safety evaluation, and a mandatory remapping procedure (Day 75 ± 15) for PVI durability assessment. Of 149 patients enrolled between February and June 2023, 140 had the study catheter inserted (safety analysis set) and 137 had ablation energy delivered (per-protocol analysis set). The median (Q1/Q3) total procedure and fluoroscopy times were 108.0 (91.0/126.0) and 4.2 (2.3/7.7) min (n = 137). The acute procedural success rate was 100%. First-pass isolation was achieved in 89.1% of patients and 96.8% of veins. Cavotricuspid isthmus ablations were successfully performed in 12 patients [pulsed field (PF) only: 6, RF only: 5, and RF/PF: 1]. The PAE rate was 4.4% [6/137 patients; 2 pulmonary vein (PV) stenoses, 2 cardiac tamponades/perforations, 1 stroke, and 1 pericarditis]. No coronary artery spasm was reported. No oesophageal lesion was seen in the EE subset (0/31, 0%). In the NA subset (n = 30), microemboli lesions were identified in 2 patients (2/30, 6.7%), both of which were resolved at follow-up; only 1 was symptomatic (silent cerebral lesion, 3.3%). In the CT/MRA subset (n = 30), severe PV narrowing (of >70%) was detected in 2 patients (2/30, 6.7%; vein level 2/128, 1.6%), of whom 1 underwent dilatation and stenting and 1 was asymptomatic; both were associated with high index values and a small inter-tag distance. In the PV durability subset (n = 30), 100/115 treated PVs (87%) were durably isolated and 18/30 patients (60.0%) had all PVs durably isolated. A DE focal CF catheter with 3D mapping integration showed a 100% acute success rate with an acceptable safety profile in the treatment of paroxysmal AF. Prespecified 3-month remapping showed notable PVI durability. ClinicalTrials.gov Identifier: NCT05752487.

Accurate substrate characterisation may improve the evolving understanding and treatment of cardiac arrhythmias. During substrate-based ablation techniques, wide practice variations exist with mapping via dedicated multi-electrode catheter or conventional ablation catheters. Recently, newer ablation catheter technology with embedded mapping electrodes have been introduced. This article focuses on the general misconceptions of voltage mapping and more specific differences in unipolar and bipolar signal morphology, field of view, signal-to-noise ratio, mapping capabilities (density and resolution), catheter-specific voltage thresholds and impact of micro-, mini- and multi-electrodes for substrate mapping. Efficiency and cost-effectiveness of different catheter types are discussed. Increasing sampling density with smaller electrodes allows for higher resolution with a greater likelihood to record near-field electrical information. These advances may help to further improve our mechanistic understanding of the correlation between substrate and ventricular tachycardia, as well as macro-reentry arrhythmia in humans.

Aims: Pulsed field ablation (PFA) for pulmonary vein isolation (PVI) combines the benefits of high procedural efficacy and safety. Transseptal puncture (TSP) to obtain left atrial (LA) access during PVI remains an important source of complications during LA procedures. For PFA procedures, TSP is generally performed using a standard transseptal sheath that is then exchanged over the wire for a dedicated PFA sheath, which might be a potential source for air embolism. We aimed to prospectively evaluate the feasibility and safety of a simplified workflow using the PFA sheath (Faradrive, Boston Scientific) directly for TSP.Methods and Results: We prospectively enrolled 100 patients undergoing PVI using PFA at two centres. TSP was performed using the PFA sheath and a standard 98 cm transseptal needle under fluoroscopic guidance. TSP via the PFA sheath was successfully performed in all patients and no complications occurred. The median time from the first groin puncture to the completed LA access was 12 min (IQR 8–16 min).Conclusion: An over-the-needle TSP directly with the PFA sheath proved feasible and safe in our study. This simplified workflow has the potential to reduce the risk of air embolism, to shorten procedure time, and to reduce cost.

Background and Aims: The multicentre, single-arm SmartfIRE study assessed the safety and effectiveness of the novel dual-energy THERMOCOOL SMARTTOUCH SF (DE STSF) contact-force sensing catheter with multimodality generator to deliver radiofrequency (RF) and unipolar biphasic pulsed field (PF) ablation. Three-month follow-up showed a 100% acute success rate with an acceptable safety profile. Results at 12 months post-ablation are summarised here. Methods: Patients with symptomatic paroxysmal atrial fibrillation underwent pulmonary vein isolation (PVI) with the recommendation of PF ablation at posterior/inferior and RF ablation at the anterior/ridge/carina segments. The 12-month effectiveness endpoint was freedom from documented symptomatic and asymptomatic atrial arrhythmia on or off antiarrhythmic therapy (assessed by electrocardiogram, remote arrhythmia monitoring, and 24-hour Holter), including acute procedural failures. Safety was assessed as the incidence of serious adverse events (SAEs) related to device and/or procedure. Quality of life was evaluated via Atrial Fibrillation Effect on Quality-of-Life (AFEQT) scores and healthcare utilisation was assessed as hospitalisation for cardiovascular events and antiarrhythmic drug (AAD) use. Results: Of 149 patients enrolled, 140 had the study catheter inserted (safety population analysis set) and 136 met the eligibility criteria and had ablation energy delivered (per-protocol analysis set). Freedom from symptomatic and asymptomatic atrial arrhythmia at 12 months was 71.5% (84.2% when using standard-of-care monitoring only). The clinical success rate (freedom from symptomatic arrhythmia) was 86.4%, and single procedural success was 81.0% (n=136). The rate of device and/or procedure related SAEs was 3.6% (5/140 patients; 2 cardiac tamponades, 2 pulmonary vein stenosis, 1 anaphylactic shock). At 12 months, the overall AFEQT score increased by a median 26.9 points versus baseline. Cardiovascular hospitalisation rate reduced from 20.1% to 11.9% during the 12 months before versus after ablation, respectively. The use of Class I/III AAD decreased from 60.3% at baseline to 23.9% at 6 to 12 months post-ablation. Post hoc analysis showed that patients with high adherence to recommended inter-tag distance and PF/RF index during ablation (n=47) had a 12-month freedom from atrial arrhythmia recurrence of 86.9%, while the remaining patients (n=88) had the rate of 64.0%. Conclusion: The 12-month follow-up of the SmartfIRE study demonstrated the effectiveness, safety, and healthcare benefits of ablation using the DE STSF platform.