Introduction: Pulsed field ablation (PFA) is a "single-shot" non thermal ablation modality for atrial fibrillation (AF). In general, obesity is associated with increased risk of AF recurrence after catheter ablation with thermal energy sources. Purpose: We aimed to assess the impact of body mass index (BMI) on procedural characteristics, safety, acute efficacy and long-term outcomes of PFA for symptomatic AF. Methods: Of 1233 subjects enrolled in the EU-PORIA registry, in our subanalysis we included 1055 patients undergoing de novo pulmonary vein isolation (PVI)-only ablation procedure for symptomatic AF using the pentaspline PFA catheter from March 2021 until May 2022 at seven high-volume European centers. Patients were divided into two groups based on BMI: normal weight (nW, < 25 kg/m2) and overweight (oW, ≥ 25 kg/m2). Overweight patients were further categorized into three subgroups: pre-obesity (pOb, 25-29.9 kg/m2), obesity (Ob, 30-34.9 kg/m2) and severe obesity (sOb, ≥ 35 kg/m2). Clinical and procedural characteristics, complications and follow up data were collected. Results: A total of 1055 patients (39% female, mean age 65,7±10,9 years, 65% paroxysmal AF) were enrolled. 32% of patients were normal weight (nW) and 68% overweight (oW). Among oW group, 438 subjects (41%) were assigned to pOb group, 204 (19%) to Ob, and 71 (7%) to sOb. Acute PVI was achieved in 100% of cases. The median skin-to-skin procedure and the median fluoroscopy time were similar between nW and oW and in all investigational subgroups, but radiation exposure increased in line with BMI (p<0.001). Periprocedural complications were 5% in nW, 1.6% in pOb, 3.9% in Ob, and 2.8% in sOb (p=0.06). The Kaplan-Meier estimate of arrhythmia-free survival was 80.2% in nW and 71.9% in oW (p=0.017). Each unit increment in BMI was associated with 4.2% increase in risk of AF/AT recurrence. Severe obese patients presented the highest 1-year AT/AF recurrence rate (37.2%). In the sOb group the rate of recurrence was not influenced by the type of AF (PAF 65.7% vs. pers AF 59.4%; p=0.484). Conclusion: Overweight patients seem to experience more AF recurrences even after PFA PVI, mainly driven by a higher recurrence rate for BMI ≥ 35 kg/m2. Weight reduction programs remain crucial, nevertheless, reduced procedural times, good safety profile and acceptable 1-year observed AF/AT freedom make PFA a feasible strategy for AF rhythm control in patients with BMI ≥ 25 kg/m2.Freedom from AF/AT recurrence

Background. Adults with congenital heart disease (ACHD) are often affected by cardiac arrhythmias requiring catheter ablation. Catheter ablation in this setting represents the treatment of choice but is flawed by frequent recurrencies. Predictors of arrhythmia relapse have been identified, but the role of cardiac fibrosis in this setting has not been investigated. The aim of this study was to determine the role of the extension of cardiac fibrosis, detected by electroanatomical mapping, in predicting arrhythmia recurrencies after ablation in ACHD. Materials and Methods. Consecutive patients with congenital heart disease and atrial or ventricular arrhythmias undergoing catheter ablation were enrolled. An electroanatomical bipolar voltage map was performed during sinus rhythm in each patient and bipolar scar was assessed according to the current literature data. During follow-up, arrhythmia recurrences were recorded. The relationship between the extent of myocardial fibrosis and arrhythmia recurrence was assessed. Results. Twenty patients underwent successful catheter ablation of atrial (14) or ventricular (6) arrhythmias, with no inducible arrhythmia at the end of the procedure. During a median follow-up period of 207 weeks (IQR 80 weeks), eight patients (40%; five atrial and three ventricular arrhythmias) had arrhythmia recurrence. Of the five patients undergoing a second ablation, four showed a new reentrant circuit, while one patient had a conduction gap across a previous ablation line. The extension of the bipolar scar area (HR 1.049, CI 1.011–1.089, p = 0.011) and the presence of a bipolar scar area >20 cm² (HR 6.101, CI 1.147–32.442, p = 0.034) were identified as predictors of arrhythmia relapse. Conclusion. The extension of the bipolar scar area and the presence of a bipolar scar area >20 cm² can predict arrhythmia relapse in ACHD undergoing catheter ablation of atrial and ventricular arrhythmias. Recurrent arrhythmias are often caused by circuits other than those previously ablated.

Background: Epicardial mapping and ablation of ventricular tachycardia (VT) are used in different clinical situations but pericardial adhesions following prior cardiac surgery or previous epicardial procedures may limit a percutaneous approach. The objective of this case series is to evaluate the safety and feasibility of a hybrid approach with surgical epicardial access as a valid alternative when pericardial space is not accessible percutaneously. Methods: After a complete preprocedural evaluation, four patients with prior cardiac surgery underwent hybrid VT ablation under general anesthesia. Surgical subxiphoid access was performed in three cases and one patient was subjected to median resternotomy for concomitant open-heart surgery. Epicardial electroanatomic voltage maps were acquired using the CARTO 3 system (Biosense Webster) or NavX (St. Jude Medical) and VT ablations with irrigated catheters were performed. The procedural endpoint was VT non-inducibility and/or LAVA/LP abolition. Results: No serious periprocedural complications occurred after hybrid VT ablation. Three patients had no complex ventricular arrhythmias after a median follow-up of 43 months. A symptomatic sustained VT relapsed in one patient, without requiring a redo ablation procedure but responded to escalation of antiarrhythmic therapy. Conclusions: A carefully planned hybrid VT ablation with surgical epicardial access is a safe and feasible procedure in patients with epicardial scar-related re-entry circuits and pericardial adhesions that limit a percutaneous approach.