BACKGROUND:Scar-related atrial flutter (AFL) comprises complex reentrant atrial arrhythmias arising from areas of slow conduction typically in the setting of previous ablation, cardiac surgery, or atrial cardiomyopathy. 3-dimensional electroanatomic mapping is essential to define these complex circuits. OBJECTIVE:This study evaluated the feasibility of mapping and ablation of AFL using the Affera mapping and ablation system. METHODS:This single-center retrospective study included consecutive patients who underwent high-density mapping and catheter ablation of scar-related AFL using the Sphere-9 catheter and Prism-1 software. The primary efficacy outcome was defined as termination of the AFL at the initial ablation site or within the surrounding area. Secondary efficacy outcomes were termination of AFL with ablation at any site and AFL recurrence on/off antiarrhythmic drugs during follow-up. RESULTS:A total of 65 patients were included. Most patients had undergone ≥1 previous atrial fibrillation ablation procedure (87.7%). Median mapping time was 8 minutes (6-10), with a median number of points acquired on activation maps of 835 (510-1175) for the right atrium and 1859 (1418-2531) for the left atrium. Termination of the clinical AFL at the initial ablation site or surrounding area was achieved in 79.4% of patients. Termination of AFL with ablation at any site was achieved in all patients. During a median follow-up of 69 days (49-116), AFL recurrence occurred in 15% of patients. CONCLUSION:The study results demonstrate the feasibility of the Affera 3-dimensional electroanatomic mapping system to successfully map and ablate scar-related AFLs.

Abstract Background Electrical isolation of the left atrial appendage (LAA) has been shown to reduce arrhythmic recurrence in patients with long standing atrial fibrillation (AF); however, durable isolation remains a challenge. Purpose to demonstrate acute e chronic feasibility of LAA isolation in persistent AF patients with a focal ablation catheter toggling between radiofrequency (RF) and pulsed field energy (PFA). Methods We prospectively enrolled consecutive patients undergoing first-time persistent AF ablation with the lattice-tip PFA catheter between November 2024 and September 2025. Patients were divided int three groups according to the LAA ablation strategy at the ostium: 1) PFA 4 seconds only, (2) RF for 5seconds, 70% power, and (3) RF for 7 seconds, 90% power. The acute feasibility endpoint was LAA isolation defined as entrance and exit block after a 20-minute waiting period. Chronic feasibility was assessed as persistent LAA isolation during the LAAO procedure 3 months post-ablation. Results A total of 182 (113, 62% males) patients were included in the analysis. A total of 78 (42.8%), 43 (23.7%), and 61 (33.5%) patients were included to Groups 1, 2, and 3, respectively. All received PFA within the LAA body. Acute LAA isolation was achieved in all (100%) in both groups. All patients underwent repeat mapping during LAA closure after 3 months. LAA reconnection was observed in 78 (100%)patients in Group 1, 35(81.4%) in Group 2, and and none (0%) in Group 3 (p<0.001). Conclusion Acute LAA isolation with the lattice-tip PFA catheter was feasible across all strategies. However, in this cohort, PFA alone did not provide durable isolation, indicating that additional RF energy appears necessary to achieve chronic LAA isolation.

BACKGROUND:Catheter ablation of ventricular tachycardia (VT) in nonischemic cardiomyopathy (NICM) remains particularly challenging, as arrhythmogenic substrates are often deep and heterogeneous within the myocardium. To overcome these limitations, a novel high-voltage pulsed field ablation (hv-PFA) system is under investigation. OBJECTIVES:The aim of our study was to evaluate the safety and feasibility of hv-PFA during VT ablation. METHODS:This single-center series included consecutive NICM patients undergoing repeat ablation of recurrent monomorphic VT with an 8.5-F force-sensing hv-PFA catheter between July 2024 and August 2025. A scar homogenization approach was used in all patients. Procedural success was defined as noninducibility of any VT and absence of residual abnormal electrograms within bipolar voltage area <1.5 mV. Device and mapping system integrity was monitored during the procedure. Follow-up data were collected during in-office evaluations and remote device monitoring. RESULTS:Seven consecutive patients (mean age 58 ± 10.4 years; 1 female [14.3%]) underwent a total of 9 procedures, as 1 patient underwent 3 ablations for VT recurrence. The mean number of prior procedures was 2.29 ± 1.11. A scar homogenization strategy was applied in all procedures (median 14 lesions [Q1-Q3: 9-17 lesions]). Procedural success was achieved in all patients. During a median follow-up of 10 months (320 days [Q1-Q3: 183-407 days]), arrhythmic recurrence occurred after 3 (33.3%) of 9 procedures in 2 (28.6%) of 7 patients. Electromagnetic interference resulted in defibrillator malfunction in 2 (22.2%) procedures, requiring generator replacement, and mapping system malfunction in 3 (33.3%) procedures. CONCLUSIONS:Preliminary findings from this prospective series show efficacy of hv-PFA in NICM patients with prior multiple unsuccessful VT ablations. Further studies are required to define the safety profile of this novel ablation system.

BACKGROUND:Pulsed field ablation (PFA) has emerged as a nonthermal alternative for catheter ablation of atrial fibrillation (AF). However, experience on ablation in patients with a prior left atrial appendage occlusion (LAAO) device remains limited. OBJECTIVE:This study aimed to assess the feasibility and safety of PFA in patients with an implanted LAAO device and evaluate outcomes in those undergoing a combined PFA and leak closure procedure. METHODS:We analyzed consecutive patients with a prior LAAO device who underwent PFA alone or a concomitant leak closure procedure for symptomatic AF. The primary endpoints were procedural success, defined as successful PFA delivery, and safety, defined as the absence of device dislodgment, new peridevice leaks (PDLs), and device-related thrombus (DRT). RESULTS:73 consecutive patients were included in our analysis. PFA was performed using the Farapulse and Affera systems in 45 (61.6%) and 28 (38.4%) patients, respectively. Concomitant PDL closure was performed in 18 patients (24.6%). The combined procedural endpoint was achieved in 70 patients (95.9%). At 2-month transoesophageal echocardiography follow-up, no new PDLs, device-related thrombus, or dislodgment were detected in patients undergoing PFA alone, whereas 2 patients (11.1%) in the combined procedure group had residual leaks. The use of radiofrequency was necessary in 3 patients with an Amulet device to isolate the LAA. CONCLUSION:Our findings suggest that PFA in patients with an implanted LAAO device is feasible. The combined approach of PFA and leak closure demonstrated high procedural efficacy.

Background Persistent left atrial appendage (LAA) thrombosis in patents with contraindications or who are refractory to intensive antithrombotic therapy remains a clinical challenge. Although LAA closure with limited manipulation is performed in patients with small distal nonmobile thrombi, larger more proximal mobile thrombi are usually deemed a contraindication to percutaneous LAA closure due to the inherent risk of iatrogenic thromboembolism. In this population, percutaneous aspiration thrombectomy (AT) is a potential treatment modality. Objectives In this study the authors describe their experience with percutaneous AT. Methods This was a 4-center case series of 22 consecutive patients who underwent percutaneous LAA AT before closure for the presence of a persistent LAA thrombus. Large-bore (≥12-F) AT was performed either manually (n = 16 [a 60-mL syringe was used in 14 patients and AlphaVac System in 2 patients]) or mechanically using the pump-assisted Indigo system (n = 6). Results Percutaneous AT was technically successful in all patients, achieving evacuation of the LAA thrombus and allowing subsequent LAA closure with either a Watchman (n = 21) or Lariat (n = 1) device without AT-related complications. Conclusions Percutaneous AT followed by LAA closure is safe and feasible when performed by experienced operators proficient in left atrial interventional procedures. It may offer an alternative to surgery in patients with a proximally located persistent LAA thrombus.

BACKGROUND:The safety and efficacy of pulsed field ablation for pulmonary vein and posterior wall isolation in atrial fibrillation ablation are well established; however, evidence regarding its use in extra-pulmonary vein areas remains limited. The aim of this study was to assess the feasibility and durability of pulsed field ablation for coronary sinus (CS) and left atrial appendage (LAA) isolation and mitral isthmus (MI) ablation. METHODS:We analyzed data from consecutive patients who underwent repeat atrial fibrillation ablation with pulsed field ablation between February and October 2024. MI ablation, CS isolation, and LAA isolation were attempted in all patients using the Farapulse (Boston Scientific) ablation system. Acute isolation was assessed after a 20-minute waiting period and an adenosine challenge, while chronic durability was evaluated during a repeat procedure for LAA closure at 3 months. RESULTS:A total of 236 patients (145, 61.4% men) were included in our analysis. Acute CS isolation was achieved in 147 (62.2%) patients for the CS and in all patients for the LAA. Acute MI block was obtained in all patients. After a 20-minute waiting time, the adenosine challenge revealed dormant conduction in 52 (26.4%) cases for the CS, in 4 (1.7%) for the LAA, and MI block regression in 35 (14.8%). All patients underwent remapping at the time of left atrial appendage occlusion, which showed CS and LAA isolation in only 3 (1.3%) and 10 (4.6%) patients, respectively, and MI block in 13 (5.5%) cases. CONCLUSIONS:Pulsed field ablation is a feasible and acutely effective method for CS and LAA isolation and MI block; however, lesion durability remains a significant limitation.

AIMS:Pulsed Field ablation (PFA) is a non-thermal ablation modality with functional myocardial sparing. Recent evidence suggests that clinically used PFA systems may produce non-negligible thermal effects, particularly at the tissue-catheter interface, potentially increasing the risk of thrombo-embolic complications. This study sought to characterize the temperature dynamics of two PFA pulse waveforms, delivered using a variable-loop circular catheter, under different irrigation conditions. METHODS AND RESULTS:In total, 132 ablations were performed on 31 bovine myocardial tissue specimens, using Sequence_1 and Sequence_2 at two different irrigation rates-4 and 30 mL/min. Maximum temperatures and their rise from baseline were measured at the tissue surface, and at 3 and 7 mm depths, across different ablation conditions. Sequence_1 at 4 mL/min produced the highest surface temperature (56.4°C [54.9-58.4]) and temperature rise (ΔT: 19.4°C [17.9-21.4]). Sequence_2 at 30 mL/min showed the most favourable thermal profile, with significantly lower surface temperatures (40.8°C [37.9-43.0], ΔT: 3.8°C [0.9-6.0], P < 0.0001). At 3 mm depth, temperature increases were reduced for all settings, but remained highest with Sequence_1 at 4 mL/min (42.5°C, ΔT: 5.5°C). At 7 mm depth, temperatures remained close to baseline. Both waveform and irrigation optimization independently and synergistically reduced tissue heating, with the Sequence_2 at 30 mL/min achieving the lowest thermal load at all depths. CONCLUSION:This study confirms that PFA can induce relevant thermal effects, especially at the tissue interface. However, waveform optimization and active cooling significantly mitigate these effects. Such strategies to minimize thermal effects should be implemented in clinical practice to enhance procedural safety.

Not applicable. Pulsed field ablation (PFA) has been increasingly adopted for catheter ablation of atrial fibrillation, owing to its increased procedural efficiency when compared to radiofrequency ablation. Due to its non-thermal and relatively tissue-selective mechanism of action, PFA does not carry many of the traditional risks associated with thermal ablation,but real-world experience has shown that other non-traditional, PFA-specific ablation risks can occur. Among these, hemolysis, coronary artery involvement (spasm and fibrosis), and profound vagal responses have been increasingly reported when using this technology. Herein, we will review the current understanding of the pathophysiology, clinical implications, and prevention or treatment strategies for these PFA-specific ablation risks.

BACKGROUND Earlier studies have documented the risk for sinoatrial node injury and phrenic nerve paralysis as complications following radiofrequency catheter ablation for electrical isolation of the superior vena cava (SVCI). OBJECTIVES The aim of this study was to assess the safety and feasibility of SVCI in patients with atrial fibrillation undergoing pulsed field ablation (PFA) METHODS A total of 1,600 consecutive patients undergoing PFA for pulmonary vein isolation plus SVCI were included in this multicenter analysis. Superior vena cava (SVC) ablation was performed under the continuous guidance of intracardiac echocardiography. The PFA catheter was placed at the junction between the SVC and the right atrium at the level of the lower border of the pulmonary artery. A total of 4 applications were given to achieve complete electrical isolation of the SVC. Sinus node injury and phrenic nerve stunning were checked during the procedure, before discharge, and at 2-month follow-up. RESULTS A total of 616 patients receiving SVCI were included in the analysis. Acute SVCI was achieved in all 616 patients (100%). In the flower configuration used in the first 10 patients, 2 transient sinus node injuries and 2 episodes of phrenic nerve stunning were observed, which resolved spontaneously during the procedure. In the remaining patients, the basket configuration was used; only 1 episode of phrenic nerve stunning was registered, which regressed before the end of the procedure. No permanent damages were registered at discharge and at 2-month follow-up. CONCLUSIONS Intracardiac echocardiography-guided PFA can effectively isolate the SVC with a good safety profile. (JACC Clin Electrophysiol. 2025;11:752-760) (c) 2025 by the American College of Cardiology Foundation.