Abstract Background Prior experiences from preclinical studies indicate the critical need of catheter-tissue- contact for creation of consistent transmural lesions in pulsed-field ablation (PFA). Intracardiac echocardiography (ICE) not only provide real-time visualization of cardiac structures, but also ensure adequate contact with the tissue. Objective We evaluated ablation outcome and reconnection rate following ICE-guided PFA procedure in patients with atrial fibrillation (AF). Methods Consecutive patients receiving ICE-guided PFA procedure were included in this multi-center analysis. All patients received isolation of PVs (PVI). Additional ablation of left atrial posterior wall (LAPW) was decided based on operator’s discretion. Concentric overlapping lesions were placed in the LAPW. Number of applications were determined on a case-by-case basis. ICE and fluoroscopy were used to optimize contact between the PFA catheter and the targeted tissue. All procedures were performed under uninterrupted anticoagulation. Mapping was done before and after ablation to confirm electrical isolation. Arrhythmia-monitoring was done for 1-year with periodic clinic visits, event recorders and 7-day Holter monitoring. Results A total of 372 patients [age: 62.69 ± 10.41 years, male: 201 (71.3%), paroxysmal AF: 67 (18%)] were included in this analysis of which 48 (12.9%) underwent PVI-only and the remaining subjects received additional ablation of LAPW. Mean number of applications were 34.67 ± 8.88 and 73.65 ± 37.21 for PVI-only and PVI+LAPWI cohorts respectively (p<0.001). No major procedural complications such as esophageal injury, atrio-esophageal fistula, pericardial effusion requiring drainage or cerebrovascular accidents were reported. During 1-year follow-up, 38 (10.2%) patients underwent repeat procedure for recurrence. Reconnection of PV and LAPW were found in only 2 (5.2%) patients. In all 38 patients, new triggers initiating AF were detected to be originating from interatrial septum: 25 (65.8%), superior vena cava: 9 (23.7%), coronary sinus: 7 (18.4%) and left atrial appendage: 6 (15.8%). Conclusion ICE-guided PFA procedures are safe and produce durable lesions leading to very low reconnection rate. The recurrence was mostly due to new triggers initiating AF.

Abstract Introduction The demographic data shows a growing population, mostly elderly and with multiple comorbidities, therefore becoming increasingly frail. In this context Atrial fibrillation (AF) is the predominant sustained arrhythmia, and over the years trans-catheter isolation of pulmonary veins (PVI) has become a crucial approach in AF treatment. Among the technologies and energy resources employed through the years to perform atrial fibrillation transcatheter ablation, a novel technique has recently begun to gain ground, specifically pulsed-field ablation (PFA). PFA employs sequential brief and high amplitude electrical pulses to induce selective and irreversible electroporation of the myocardium, leading to cell death. The high selectivity of the lesion, ensured by the lower electroporation threshold of myocardial tissue compared to adjacent anatomic structures, allows for a decrease in potential complications associated with conventional thermal ablation. Purpose To assess the efficacy and safety in the use of pulsed field ablation in a selected population of elderly and frail patients undergoing atrial fibrillation ablation. Method We conducted a retrospective study focusing on elderly and frail patients admitted to our centre for paroxysmal or persistent AF ablation. The inclusion criteria were: age greater than 75 years and a Clinical Frailty Scale ≥ 5. The study population consisted of 26 patients [male gender 18, mean age 78 ± 3 years] including 8 who were affected by an oncological or haematological disease at the time of admission. The majority of patients were affected by paroxysmal AF while two of them presented persistent AF (9%). The primary ablation endpoint was the pulmonary vein isolation (PVI) that was achieved by delivering an energy of 2 kV over 8 applications, employing an alternating approach between the two configurations of the basket and flower catheter for each individual vein. Results The short-term success, represented by the complete and verified electrical isolation of the veins was achieved in all 26 patients without any periprocedural complications. First-pass pulmonary vein isolation (FPI) was universally achieved among the patient in study, with a mean skin-to-skin procedural time of 70 ± 30 minutes. From the procedural data perspective, ablation was achieved using an average fluoroscopy time of 22 ± 8.4 minutes and an average dose area product (DAP) of 1320 cGy×cm2. Conclusions In elderly and frail patients, we assessed the efficacy and safety of ablative procedures using the PFA technique. Successful electrical PVI was achieved without additional touch-ups, thanks to a high FPI rate. This results in lower procedural times and shorter intra-operative radiation exposure. These data confer an augmented value within the elderly-frail population, wherein shorter procedural times contribute to a better postoperative course, characterized by reduced bed rest and shorter intra-hospitalization periods.

Abstract Background The HeartLogic algorithm integrates data from various implantable defibrillator (ICD) sensors to predict impending heart failure (HF) decompensation. The algorithm computes worsening in its sensors and weighs them based on a risk level. These sensors include accelerometer-based first (S1) and third (S3) heart sounds, intrathoracic impedance (TI), respiration rate (RR), the ratio of respiration rate to tidal volume (RSBI), and night heart rate (NHR). Objective This study assessed the relative worsening of ICD sensors at the onset of HeartLogic alerts, their association with patient characteristics and subsequent outcomes. Methods The HeartLogic feature was activated in 568 ICD patients (410 with CRT-D) across 26 centers, with a median follow-up of 26 months [25th–75th percentile: 16–37]. Results During the follow-up, 1200 HeartLogic alerts were recorded in 370 patients. The sensor with the highest worsening (SHW) at the alert onset was S3 (27% of alerts), followed by S3/S1 (25%), TI (16%), RR (15%), and NHR (11%), RSBI (6%). Patients with atrial fibrillation (AF) at implantation and those with chronic kidney disease (CKD) had higher alert prevalence (AF 84% vs. no-AF 58%, CKD 72% vs. no-CKD 59%; both p <0.05) and higher alert rates (AF 1.51/patient-year vs. no-AF 0.88/patient-year, CKD 1.30/patient-year vs. no-CKD 0.89/patient-year; both p <0.05). AF patients had alerts with every sensor as SHW, while CKD patients had alerts primarily with TI, RR, and RSBI as SHW (Figure). In 85% of cases among 247 patients with >1 alert, the SHW changed between successive alerts. Of the 88 (7%) alerts resulting in HF hospitalizations or deaths, a greater proportion featured RR or RSBI (11%) and NHR (11%) as SHW, followed by heart sounds (5%) (both p <0.05). Clinical events were more common with the first alert (12.6%) than subsequent alerts (5.2%, p <0.001). Conclusion HeartLogic alerts are predominantly associated with the highest worsening in heart sounds. Nevertheless, recurrent alerts often involve other sensors, suggesting varied HF progression mechanisms and potential divergent outcomes. The frequency of alerts and the pattern of worsening in ICD sensors are linked to patient characteristics.

Abstract Background It is well known that age affects the efficacy of pharmacological treatment for atrial fibrillation (AF). Thermal ablation (radiofrequency or cryoballoon) is an established strategy for AF. However, there is no evidence evaluating efficiency, effectiveness, and safety outcomes in elderly patients in the context of the novel pulsed-field ablation (PFA) technology. Purpose We aimed to analyze the efficacy and safety of PFA in elderly (age≥75 years) patients with AF compared to non-elderly (age&lt;75 years) patients with AF. Methods All consecutive patients undergoing AF ablation with the Farapulse system at 10 centers were included. Protocol-directed PVI was delivered using 2000 V with eight applications per vein, that is, four applications each in the basket and flower poses. Additional lesions were performed at the operator’s discretion. Results A total of 851 consecutive patients were included: 83 (9.8%) had ≥75 years (median of 77[75-78] years) whereas 768 (90.2%) had &lt;75 years (median of 62[56-68] years, p&lt;0.0001). Older patients had more comorbidities compared to younger patients (kidney disease: 9.6% vs 1.2%, p&lt;0.0001; chronic obstructive pulmonary disease: 8.4% vs 3%, p=0.021; cancer history: 18.1% vs 6.1%, p=0.0004; hypertension: 61.4% vs 43.8%, p=0.002), whereas they exhibited a higher LVEF (60±6% vs 57±8%, p=0.0243). No differences between older and younger patients were found in terms of underlying AF type (paroxysmal AF: 66.3% vs 68.9%, p=0.62), procedure type (repeat ablation: 8.4% vs 13.4%, p=0.29), more extensive lesion set than PVI only (28.9% vs 22.5%, p=0.22) and the use of 3D mapping system (22.9% vs 21.1%, p=0.67). By looking at procedural metrics, no differences were also found between groups: 73±28 min vs 72±32 min for skin-to-skin time, p=0.41; 93±41 min vs 88±43 min for preparation plus skin-to-skin time, p=0.11; 18±9 min vs 17±9 min for fluoroscopy time, p=0.61 and 32[32-40] vs 32[32-38] PFA spots to achieve PVI, p=0.29. PVI was achieved in all patients. No major procedure-related adverse events were reported. Conclusion In our experience, the use of Farapulse PFA system for AF ablation in elderly patients was rapid, safe and effective, with no differences compared to the younger population.

Abstract Background Catheter ablation (CA) with pulmonary vein isolation (PVI) is an optimal treatment option in patients with paroxysmal atrial fibrillation (AF). PVI alone in patients with persistent AF has proved to have suboptimal results. Ablation of additional atrial structures, such as posterior wall (PW) and left atrial appendage has been investigated as a tool to improve procedural efficacy. Recently very high-power short-duration (vHPSD) ablation was developed to allow rapid PVI, limiting complication through the maximization of resistive heating, and minimization of conductive heating. Objectives Compare PVI plus PWI using vHPSD versus standard-power (SP) ablation index-guided CA among consecutive patients with persistent AF Methods Forty consecutive patients underwent PVI plus PW isolation using vHPSD, compared to 40 controls underwent standard power (SP) PVI plus PW isolation. The primary efficacy endpoint outcome was recurrence of atrial tachyarrhythmias after a 3-month blanking period. The primary safety outcome was a composite of major complications within 30 days of CA. Results Treated patients have a median age of 62.8±9 years, 68 (85%) are male. Median left atrial volume is 42.4 (36-50) ml/m2. 61 (78.8%) patients had never undergone catheter ablation before. There are no statistically significant differences between groups. PW isolation was obtained more commonly in the vHPSD compared to the SP group (98% vs. 75%, p=0.007), despite shorter procedure and fluoroscopy times (p<0.001). Survival free from recurrent atrial tachyarrhythmias at 18 months was 68% in the vHPSD and 47% in SP groups, respectively (log-rank p=0.071), without major adverse events. The vHPSD approach was significantly associated with reduced risk of recurrent AF at multivariable analysis (HR, 0.39, p=0.030). Conclusions The results show feasibility and safety of posterior wall vHPSD ablation for persistent AF using this new temperature-controlled catheter without intraprocedural and periprocedural major complications at follow-up. vHPSD ablation for PW isolation may be more effective in term of atrial tachyarrhythmias recurrences with a trend for superior efficacy. However, this remains a single center experience in a small group of patients. Comparative trials involving greater number of patients with long-term follow-up are necessary to definitive results.

Abstract Background Pulsed Field ablation (PFA) has recently emerged as a treatment strategy for patients with atrial fibrillation (AF) and early studies showed promising procedural data and durable pulmonary vein isolation (PVI). However, Very High-Power Short-Duration ablation (VHPSD) has previously reported good efficiency and mid-term outcomes, and only a few works compared these two procedures, especially in patients with persistent AF. Objective Our aim is to compare these different modalities of transcatheter ablation in patients with persistent AF, focusing mainly on some procedural aspects, safety and efficacy. Methods We performed a retrospective observational study enrolling all consecutive patients with persistent AF from September 2021 to May 2023 undergoing transcatheter ablation with PFA or VHPSD. In the first group, PVI was achieved by 2kV pulses with eight applications to each vein using both catheter configurations, while isolation of the posterior wall of the left atrium was achieved by applications through the only "flower" configuration; additional lesions were then added at the operator's discretion. In the second group, PVI was achieved by delivering 90W radiofrequency pulses for 4 seconds in the posterior portions of the left atrium and 50W pulses in the anterior region of the pulmonary veins; additional lesions were occasionally applied. All patients received general anaesthesia or deep sedation with fentanyl and dexmedetomidine. Results A total of 79 patients were included, n = 24 (30%) in the PFA group and N = 55 (70%) in the VHPSD one: early persistent AF (n= 2 [8,3%]; N = 7 [12,7%]), persistent AF (n= 17 [70,8%]; N = 36 [65,5%]), long-standing persistent AF (n= 5 [20,8%]; N = 12 [21,8%]). The two populations showed similar clinical features: CHA2DS2-VASc (median value 3 [0-6] in PFA vs 2 [0-6] in VHPSD, p = 0,10), indexed left atrial volume (mean value 42,6 ml/m² in PFA vs 42,4 ml/m² in VHPSD, p = 0,07) and EF (mean value 55,4% in PFA vs 54,8% in VHPSD, p = 0,33). PVI was successfully achieved in all patients. Nevertheless, the PFA group was associated with shorter procedural duration (92,1 ± 36,9 vs 134,2 ± 36,1 minutes, p = 0,00001) but longer fluoroscopy time (25,5 ± 9,3 vs 17,4 ± 11,5 minutes, p = 0,001); it also showed a lower rate of minor complications (n = 1 [4,2%] vs N = 3 [5,5%], p = 0,057), even though serious complications were not observed in either group. After a median follow-up of 14 (9-26) months, n = 19 [79.2%] in the PFA and N = 43 [78.2%] in the VHPSD population were free of any atrial arrhythmia (p = 0,92). Conclusion PFA allows faster procedures, representing a major advantage for the operator and the patient, who is at lower risk of peri-procedural complications. On the other hand, VHPSD correlates with shorter fluoroscopy times, reducing exposure to ionizing radiation. Finally, the two procedures show similar mid-term efficacy in terms of recurrence-free time.

Abstract Background Brugada Syndrome (BrS) is a rare genetically based channelopathy responsible for malignant arrhythmias and sudden cardiac death (SCD) in young adults. Objectives The aims was to evaluate prognostic indicators useful for accurate arrhythmic risk stratification in BrS by studying genetic, clinical, anamnestic, instrumental parameters, and those derived from electrophysiological study (EPS) and intracavitary mapping. Materials and Methods 209 patients with Brugada type 1 were recruited between 01/01/2018 and 01/10/2023. Results In the first study, predictive factors related to high arrhythmic risk from the data obtained for the total population of 209 Brugada patients enrolled in our case series include a positive history of cardiogenic syncope (p value 0.000041), having had a resuscitated cardiac arrest (p value 0.00025), presenting positive EPS for inducibility of ventricular tachycardia (p value 0.00032), having a family history of sudden cardiac death (p value < 0.00001), and presenting positive cardiac mapping and MRI for pathological alterations (both with p value > 0.00001). From the data obtained for the subset of 80 Brugada patients with ICD in our case series, predictive factors related to high arrhythmic risk are different from the previously analyzed population: presenting spontaneous type 1 ECG (p value 0.0015), having had a resuscitated cardiac arrest (p value 0.014028), having a family history of sudden cardiac death (p value < 0.00001), and presenting positive mapping, genetics, and cardiac MRI for pathological alterations. Positive EPS and syncope in this subset do not appear to be risk factors, unlike the population of all 209 enrolled patients. Conclusions Multiparametric scores, including the mentioned markers, have been introduced in clinical practice for a better approach in selection. However, new markers are needed to improve risk stratification in BrS patients, especially those in the so–called "gray zone" with intermediate risk. In the future, it will be evaluated through experimental models and genotype–phenotype integration whether such electrical heterogeneity is also associated with specific genetic or structural abnormalities and may represent a new therapeutic target for etiological treatment in BrS patients. In conclusion, there is an urgent need to develop new methods for risk stratification in Brugada syndrome that are sufficiently sensitive, specific, reproducible, and easy to apply.

Abstract Background Patients with multiple cardiovascular (CV) comorbidities are increasing users of health care globally. The decision to perform ablation of atrial fibrillation (AF) may be challenging in this population, due to the difficulty in evaluating their life expectancy and the associated procedural risk. In addition, no data have been reported on the efficiency, effectiveness, and safety outcomes for non-thermal ablation, such as electroporation with pulsed-field ablation (PFA). Purpose To evaluate procedural workflow and safety for AF ablation in these patients through a novel PFA technology (Farapulse) in a large, nationwide clinical practice. Methods Consecutive patients who had undergone PFA of AF from 10 Italian centers were included. Patients were stratified according to the numbers of several comorbidities, assigning 1 point each, including: advanced age (≥80 years), LVEF≤35%, structural heart disease, coronary artery disease, chronic kidney disease, chronic obstructive pulmonary disease, previous stroke/TIA, hyperthyroidism, cancer history, cancer ongoing, severe sleep apnea, diabetes, hypertension, dyslipidemia. Results We included 634 patients (age 62±9 years, 73% male, 67% paroxysmal AF, 88% de novo ablation procedure, LVEF 57±8%). Two-hundred-nine (33%) patients had no risk-factors, 179 (28.2%) patients had at least 1, 137 (21.6%) two, 63 (9.9%) patients 3 risk-factors and 46 (7.3%) patients more than 4 comorbidities. Patients with accumulated risk factors (≥4) had a higher percentage of long-standing AF (17.4% vs 5.4%, p=0.005) and more often underwent de novo ablation procedure (93.5% vs 81.3%, p=0.04). In these cases, operators decided to adopt more frequently, albeit not significantly, advanced diagnostic such as 3D mapping system (30.4% vs 21.9%, p=0.20) or intracardiac echocardiography (41.3% vs 29.8%, p=0.13), a general anesthesia sedation strategy (41.3% vs 32.1%, p=0.88) and a more extensive lesion set beyond PVI (i.e. left atrial posterior wall area, 32.6% vs 23.1%, p=0.15). Procedures in which patients with accumulated risk factors are involved required longer support (preparation plus skin-to-skin) time (90[65-120] min vs 72[60-100] min, p=0.02) and skin-to-skin time (70[60-100] min vs 60[55-85] min, p=0.03) compared to patients with &lt;4 risk factors, whereas time to PVI (19[14-25] min vs 20[14-25] min, p=0.81) and total number of PFA deliveries to achieve PVI (32[32-38] vs 32[32-36], p=0.55) were similar. PVI was achieved in all patients. No major procedure-related adverse events were reported. Conclusion In this preliminary experience, the use of Farapulse PFA system for AF ablation in patients with accumulated risk factors was safe and effective and resulted in similar and fast time to PVI.

Abstract Background Young (<18 years of age) patients with Brugada syndrome (BrS) are often underrepresented in BrS studies and their management, especially related to syncopal episodes, remains unclear. Purpose To describe the arrhythmia prevalence and clinical implication derived from continuous rhythm monitoring by implantable loop recorder (ILR) among patients younger than 18 years of age, and to assess the etiology behind syncope of undetermined origin. Methods A total of 147 BrS patients with ILR were enrolled in 12 international centers and divided into pediatric (age <12 years; n=77, 52%) and adolescents (age 13 to 18 years; n=70, 48%). Results Mean age was 11.3 years (36.1% females, 21.1% spontaneous type I ECG). Forty-six patients (31.2%) underwent ILR implant due to syncope. Over a median follow-up of 3.6 years, an arrhythmic event was recorded in 22.4% of patients and in the vast majority of cases it was of non-ventricular origin (44% atrial, 47% bradyarrhythmias). Predictors of arrhythmias at univariate Cox Regression analysis were spontaneous type I ECG (HR 2.1 - 95%C.I. 1.1-4.1), history of syncope (HR 3.1 - 95%CI 1.5-6.3) and age >12 years (HR 2.0 - 95%C.I. 1.0-3.3). Ventricular arrhythmias occurred in 4 patients, all with spontaneous BrS, and were related to fever in half of cases. In patients with recurrent syncope, the prevalence of truly arrhythmic syncope was 17.8%, and it was due to brady-, atrial- and ventricular arrhythmias in 40%, 20% and 40% of cases, respectively. Conclusions Continuous rhythm monitoring with ILRs in BrS pediatric patients detects a broad range of heart rhythm disturbances including life-threatening arrhythmias. Ventricular arrhythmias occur predominantly in patients with spontaneous type I ECG and in half of cases are fever-related. Despite the young age, brady- and atrial arrhythmias are overall frequent and represent the cause of arrhythmic syncope in 60% of patients. Young BrS patients with syncope of undetermined origin may benefit from ILR implant.

Abstract Background Arrhythmic mitral valve prolapse (AMVP) is characterized by an arrhythmogenic left ventricular substrate, with high prevalence of myocardial scar. Whether patients with prior mitral valve repair for mitral valve prolapse (MVP) and new-onset complex ventricular arrhythmias (VAs) after cardiac surgery have different electroanatomical substrate and arrhythmic outcomes compared with AMVP patients without prior mitral valve surgery is currently unknown. Purpose We sought to compare the electroanatomical substrate and long-term clinical outcomes of patients with new-onset complex VAs after mitral valve surgery to AMVP patients without prior surgery. Methods We conducted a multicenter, prospective, observational study, enrolling MVP patients with prior mitral valve repair and new-onset complex VAs (&gt;1000 premature ventricular contractions [PVCs]/day, nonsustained ventricular tachycardia [NSVT], and sustained VT) after cardiac surgery (group A,n=9), and patients with MVP, complex VAs and no prior surgery (group B,n=20). Each patient underwent a comprehensive diagnostic workup, including left ventricular electroanatomical mapping. Clinical-imaging data, as well as the location and segmental extension of both low-voltage areas and late potentials were assessed and compared between the two groups. The primary outcome was the occurrence of sustained VT or ventricular fibrillation(VF) during follow-up. Results In group A, complex VAs were first diagnosed after a median of 30(8-56) months following mitral valve repair. The characteristics of patients from the two study groups are presented in the Table. Patients from group A were older, sustained VT was nonsignificantly more common at baseline, the PVC count nonsignificantly higher, and LVEF nonsignificantly lower. Mitral annular disjunction was never observed in group A, while it was found in 7 patients from group B (p=0.066). At LV electroanatomical voltage mapping, bipolar and unipolar low-voltage areas (LVAs) were equally common in the two groups overall, and typically involved basal perimitral regions. However, patients from group B had concomitant bipolar and unipolar LVAs 50% of times, with larger unipolar LVAs, while patients from group A mostly showed isolated bipolar LVAs. Over a median follow-up of 15 (12-41) months, patients from group A (n=3, 33%) had slightly higher incidence of sustained VT or VF (HR: 1.91; 95% CI, 1.06-42.65; log-rank p=0.02, Figure) than patients from group B (n=2, 10%). Conclusion Compared to patients with AMVP and no prior cardiac surgery, patients with new-onset complex VAs after mitral valve repair for MVP have a slightly different clinical profile and electroanatomical substrate, characterized by predominant bipolar LVAs in the perimitral region. The long-term risk of major ventricular arrhythmias appears slightly higher in MVP patients with prior mitral valve surgery, mandating at least an equally careful risk assessment in both groups.

Abstract Introduction Artificial intelligence (AI) is a ground-breaking frontier in the analysis of intricate and extensive datasets, also within the medical domain. AI can be used to meticulously and systematically analyse data derived from electro-anatomical mapping, scrutinizing the numerical data extracted from the mapping engineering files. Purpose The primary objective of the project is to utilize machine learning methods to identify potential correlations between clinical, procedural, and substrate-mapping variables with major arrhythmic cardiac events (MaCE). Methods Machine learning algorithms were implemented using a database of 220 patients who underwent endocardial left ventricular electro-anatomical mapping (EAM). A total of 223 clinical-procedural variables were collected (analysis conducted for the 61 most interesting variables) and substrate mapping engineering files/data were extrapolated for analysis. Combinations of 4 and 5 variables are explored, resulting in 487,635 and 5,461,512 combinations, respectively. All the results obtained from all the combinations and different methods were evaluated by calculating the AUC (parameter indicating the probability that the prediction is in the correct order). For each patient, the numerical data extracted from the EAM files were assessed, specifically focusing on: 1. The late potentials extension and dispersion (%LatArea). 2. Point-to-point difference of the bipolar potential compared to the unipolar potential, with identification of regions where multiple points with high differences are clustered (%UniBip) 3. Areas of deceleration, characterized by very early and very late potentials within a short range, indicating a substantial difference in the activation timing (GradVal). Results Analyzing the best six 4-variable logistic regression models, we note that the variables that are most frequently correlated with a MaCE during follow-up are "NYHA class", "PAPs" and "GradVal" (AUC of the best models was: 0,96; 0,94; 0,91; 0,90; 0,90; 0,90). Analyzing the best six 5-variable logistic regression models emerges that the variables most frequently correlated with a MaCE during follow-up are "NYHA class", "PAPs", "GradVal", "Arrhythmic Storm", "TAPSE" and "%UniBip" (AUC of the best models was: 0,97; 0,93; 0,92; 0,92; 0,92; 0,92). EAM data added to clinical data increases the number of regression variables and the model complexity; "GradVal" and "%UniBip" seem to have greater relevance. Conclusion The study successfully employs machine learning algorithms to identify key variables influencing the prediction of MaCE. The analysis of EAM numerical data through AI can allow for the stratification of MaCE risk. The application of artificial intelligence allows to analyse a large amount of computer data that would not be analysable by human capabilities alone. Ongoing refinement and expansion of the dataset can enhance the models' predictive capabilities for clinical applications.

Background High-voltage pulses can cause hemolysis. Objectives The authors evaluated the occurrence of hemoglobinuria after pulsed-field ablation (PFA) and its impact on renal function in patients with atrial fibrillation (AF). Methods A consecutive series of patients with AF undergoing PFA were included in this analysis. The initial patients who did not receive postablation hydration immediately after the procedure were classified as group 1 (n = 28), and the rest of the study patients who received planned fluid infusion (0.9% sodium chloride ≥2 L) after the procedure were categorized as group 2 (n = 75). Results Of the 28 patients in group 1, 21 (75%) experienced hemoglobinuria during the 24 hours after catheter ablation. The mean postablation serum creatinine (S-Cr) was significantly higher than the baseline value in those 21 patients (1.46 ± 0.28 mg/dL vs 0.86 ± 0.24 mg/dL, P < 0.001). Of those 21 patients, 4 (19%) had S-Cr. >2.5 mg/dL (mean: 2.95 ± 0.21 mg/dL). The mean number of PF applications was significantly higher in those 4 patients than in the other 17 patients experiencing hemoglobinuria (94.63 ± 3.20 vs 46.75 ± 9.10, P < 0.001). In group 2 patients, no significant changes in S-Cr were noted. The group 2 patients received significantly higher amounts of fluid infusion after catheter ablation than did those in group 1 (2,082.50 ± 258.08 mL vs 494.01 ± 71.65 mL, P < 0.001). In multivariable analysis, both hydration (R2 = 0.63, P < 0.01) and number of PFA applications (R2 = 0.33, P < 0.01) were independent predictors of postprocedure acute kidney injury. Conclusions On the basis of our findings, both the number of PFA applications and postablation hydration were independent predictors of renal insult that could be prevented using planned fluid infusion immediately after the procedure.

Abstract Background Documented evidences indicate higher prevalence of non-paroxysmal atrial fibrillation (AF) as well as in elderly women but also demonstrate the need to go beyond the pulmonary veins (PV) when treating these patients. Objective We compared the ablation outcome in elderly women (>70 years) with that in men in the same age group as well as in younger women (≤70 years) undergoing pulsed-field ablation (PFA) for persistent AF (PerAF). Methods This multicenter study included consecutive PerAF patients undergoing PFA as their first procedure. Patients were divided into 3 groups: Group 1: women >70 years, Group 2: men ≥70 years and Group 3: women ≤70 years. All received PV isolation (PVI) and isolation of left atrial posterior wall (LAPWI). Concentric overlapping lesions were placed in the LAPW. Number of applications were determined on a case-by-case basis. Isolation was confirmed by electrograms recorded on the multispline catheter. In all patients, ICE and fluoroscopy were used to optimize contact between the PFA catheter and the targeted tissue. Arrhythmia-monitoring was performed for 1-year with periodic clinic visits, event recorders and 7-day Holter monitoring. Results A total of 229 patients (group 1: 73; group 2: 47 and group 3: 109) were included in this analysis. Baseline characteristics of the study population is presented in table 1. At 1-year follow-up, 15 (20.5%), 3 (6.38%) and 10 (9.17%) from group 1, 2 and 3 respectively, experienced arrhythmia recurrence off-antiarrhythmic drugs. Recurrence rate in group 1 was significantly higher than that in group 2 (p=0.034) and group 3 (p=0.029). Conclusion In women aged ≤70 years and in elderly men (>70 years), PVI plus isolation of LAPW using ICE-guided PFA was associated with significantly lower recurrence rate compared to that in the elderly women. Given the higher recurrence rate following PVI+LAPWI in the elderly females, the operators should consider addressing all other AF-initiating extra-PV triggers for better ablation-outcome in this subset of the AF population.

Abstract Introduction Radiofrequency (RF) is the most widely used technique for atrial fibrillation (AF) ablation. Aiming to achieve durable pulmonary vein isolation (PVI) with reduced procedural time and potential thermal side effects, high power short duration (HPSD) and very-high power short duration (v-HPSD) protocols have been developed, exploiting the use of the latest catheter generations. Purpose To assess safety and efficacy of AF ablation using two distinct HPSD settings, aiming to determine the most effective protocol for trans-catheter RF AF ablation. Methods We conducted a retrospective study including patients with paroxysmal or persistent AF: 100 were treated with the HPSD protocol and 100 patients with the v-HPSD one. In the HPSD protocol, RF energy at 40 W was applied for up to 20 seconds for the anterior segments of the pulmonary vein (PV), and 50 W up to 10 seconds for the posterior segments of the PV and the posterior wall (PW). Conversely, in the v-HPSD protocol RF pulses were applied at 50 W with an ablation index (AI) 500 in the anterior segments of PV and 90 W up to 4 sec for the posterior segment of the PV and the PW. Safety and efficacy were assessed during the procedure, during the hospital stay and throughout the entire follow-up duration. Results No relevant clinical and echocardiographic differences were identified between the two groups. Successful PVI and PW isolation was achieved in all cases. The v-HPSD group demonstrated a higher first-pass isolation (FPI) rate compared to the HPSD group. In contrast, the HPSD group exhibited a greater impedance drop (ID), supported by a higher contact force (CF). The RF total time, the procedural time, and the dose-area product (DAP) were significantly lower in the v-HPSD group. No periprocedural complications were reported. During the follow-up no significant differences in AF recurrence rates have been observed. Conclusions The absence of procedural complications underscores the high safety of both protocols. In our study, the v-HPSD group exhibited a superior FPI rate, indicative of enhanced acute efficacy; however it is crucial to underline that the HPSD group included a higher proportion of patients with a history of prior AF ablation. The more elevated ID observed in the HPSD group, indicating the exceptional quality of lesions, could be related to the major conductive heating component compared to v-HPSD. This results in deeper lesions and a more significant ID. Conversely, the brief duration of applications in the v-HPSD protocol contributes to reduce procedural times and diminish radiation exposure. Despite procedural disparities, the follow-up period reveals a low recurrence rate of AF in both groups, emphasizing the effectiveness of both HPSD and v-HPSD protocols in AF treatment.Kaplan-Meier Curve

Abstract Background Ventricular arrhythmias (VAs) are an important source of concern among athletes. Purpose To determine the prognostic role of non-invasive and invasive diagnostic assessments among athletes with complex VAs. Methods We included 215 athletes (83% male; 28 [19-43] years) with complex VAs in a prospective, multi-center cohort study. At baseline, each athlete underwent a prespecified comprehensive diagnostic workup, which included cardiac magnetic resonance (CMR) in 202 subjects, and electrophysiology study (EPS)/electroanatomical mapping (EAM) in 190. The primary study endpoint was the occurrence of sudden death or sustained VAs during long-term follow-up. Results During a median follow-up of 6.2 (4.4-8.1) years, 16 (7%) athletes had a primary outcome event, including one sudden cardiac death. In univariable Cox models, sustained VAs at presentation (p<0.001), uncommon VA morphology(p=0.004), syncope(p=0.005), abnormal ECG (p=0.003), VAs induction/persistence at exercise testing(p=0.021), late gadolinium enhancement (LGE;p=0.006), low-voltage areas (p=0.003) and late potentials (p<0.001) at EAM, and sustained VA induction by EPS (p<0.001) were all associated with increased risk of primary outcome events. The association of late potentials and EPS inducibility with primary outcome events was confirmed after controlling for all non-invasive predictors at univariable analysis, and the incorporation of findings of invasive tests allowed improved prediction of primary outcome events over clinical/non-invasive findings in isolation (log-likelihood ratio for nested models, p=0.043). Younger age (p=0.032), being a professional athlete (p=0.006), and absence of LGE (p=0.029) were independently associated with higher odds of uninterrupted competitive sports practice until last follow-up. Conclusions A comprehensive diagnostic assessment integrating clinical/ECG findings with CMR and EPS/EAM in selected cases may provide important prognostic information among athletes with complex VAs.

Abstract Background Lesion transmurality is an important determinant of durable effectiveness of catheter ablation (CA) for atrial fibrillation (AF). The impact of different energy sources on the achievement of transmural left atrial (LA) ablation has not been explored so far. Purpose We sought to compare the transmurality associated with pulsed field ablation (PFA) and radiofrequency (RF) ablation of LA posterior wall (PW) among patients with persistent AF. Methods Eight patients (mean age, 70±7 years; 88% male) undergoing CA for persistent AF with PW ablation and adjunctive high-density epicardial mapping were included in a multicenter international registry. In four patients, PW ablation was performed using PFA, while in the remaining four, RF energy was used with high/very-high-power short-duration settings. The primary study outcome was transmural PW isolation (PWI) with endocardial-only ablation. Results A trend towards shorter times required to complete endocardial PW ablation was observed with PFA compared to RF (9±1 vs 11±2min, p=0.065). At endocardial mapping, apparent PWI was observed in all cases. However, transmural PWI after endocardial-only ablation was demonstrated in each patient in the PFA group, but only in one RF case, in whom 50 Watt/≥10 sec settings were used (100% vs 25%, p=0.143). Interestingly, in three patients in the RF group, endocardial ablation resulted in conversion of AF into atypical flutter, which could be successfully terminated by epicardial ablation. Conclusions We observed a trend towards greater transmurality with PFA compared to high/very-high power RF ablation in the region of septopulmonary bundle. This observation may have potential implications on clinical outcomes after endocardial AF CA.

Abstract Background Pulsed Field Ablation (PFA) is an innovative technology to perform atrial fibrillation (AF) catheter ablation. No form of thermal energy is used, but an irreversible electroporation mechanism that causes selective cardiomyocytes death, sparing the cells of adjacent tissues. There are few data in the literature about peri-procedural trend of myocardium-necrosis laboratory data in patients undergoing PFA versus those with radiofrequency (RF). Purpose Compare the short-term safety and the peri-procedural trend of myocardium-necrosis laboratory data in patients undergoing PFA with those undergoing standard-power (40W) RF catheter ablation. Methods 50 patients undergoing paroxysmal AF catheter ablation with pulmonary veins isolation were retrospectively enrolled, 25 treated with PFA and 25 with RF (matched for age, sex, BMI, left atrium size). The PFA protocol involved four two-second deliveries with the penta-spline catheter in the "basket" and in the "flower" configuration; about RF ablation, circular lesions were carried out at the antrum of each pulmonary vein. All patients underwent serial blood samples including troponin I (TnI, n.v. 0-50 ng/L) and CKMB (n.v 0-5 ng/mL) at time 0 and at 3, 24 and 48 post-procedure hours. Complication were evaluated at pre-discharge visit and at 3-month follow-up. Results The clinical and echocardiographic patient’s characteristics are summarized in Table 1. The TnI and CKMB baseline values were within normal range for all patients, both those treated with PFA and those treated with RF, and there were no statistically significant differences between the two group. Regarding the TnI and CKMB values temporal increase, a statistically significant increase was observed in patients treated with PFA (Table 2). The TnI percentage decrease over the 48 hours in RF-treated patients, although not statistically significant, is slower compared to patients treated with PFA. This data could be explained by considering that PFA causes acute damage (myocardiocytes necrosis by electroporation) with less inflammation and a less progressive nature, while RF causes damage with greater irritation and progression (coagulative necrosis) that may result in myocardial necrosis even in the subsequent hours. Despite evidence of greater myocardial necrosis, there were not procedural complications in those treated with PFA. Therefore, the TnI increase is indicative of selective myocardial damage, likely more antral. Conclusion The increase of myocardio-necrosis laboratory data appears to be higher using PFA compared to RF, and it is not associated with greater adverse events. The trend of the myocardio-necrosis laboratory data shows different reduction curves between PFA and RF, probably related to different ablation power source; these data will need to be re-analysed with a greater number of cases.Table 1Table 2

Abstract Razionale. L’amiloidosi cardiaca da transtiretina (ATTR–CM), nella sua forma ereditaria o acquisita, è una cardiomiopatia a fenotipo ipertrofico–restrittivo che porta a un‘insufficienza cardiaca progressiva causata dalla deposizione extracellulare di transtiretina. Materiali e Metodi. Presso il nostro centro abbiamo avviato un ambulatorio dedicato alla gestione dei pazienti con amiloidosi cardiaca sin dal 2019. Poiché a quel tempo in Italia non erano disponibili terapie specifiche per questa condizione, decidemmo di creare un protocollo di uso compassionevole per il farmaco tafamidis in base ai risultati dello studio registrativo di fase 3. Risultati. Dopo l‘approvazione del nostro protocollo da parte dell’azienda produttrice e del comitato etico locale, a partire da ottobre 2019 e fino a novembre 2021, sono stati selezionati n=7 pazienti con ATTR–CM i quali erano idonei ricevere il farmaco (tabella 1).Dopo 22 mesi di follow–up, un paziente è deceduto per insufficienza cardiaca avanzata e un paziente ha manifestato insufficienza cardiaca che ha richiesto il ricovero in ospedale. Al termine del nostro protocollo di uso compassionevole non sono state osservate reazioni avverse al farmaco, tutti i pazienti sopravvissuti erano in classe NYHA II e hanno potuto effettuare con successo la transizione alla prescrizione ordinaria secondo i criteri del registro di monitoraggio AIFA (tabella 2). Conclusion i. Il presente rapporto descrive in dettaglio le caratteristiche della prima coorte di pazienti in Italia sottoposta a terapia farmacologica tramite uso compassionevole per il trattamento di ATTR–CM. L‘uso compassionevole è una modalità fattibile ed efficace per avviare la cura farmacologica in pazienti selezionati in attesa dell‘approvazione ufficiale da parte degli enti regolatori, il che può essere molto importante soprattutto nelle malattie ad andamento progressivo, in cui la somministrazione precoce della terapia è fondamentale per ottenere un beneficio clinico significativo.

Abstract Funding Acknowledgements Type of funding sources: None. Background Intracardiac echocardiography (ICE) is becoming more common during the ablation of atrial fibrillation (AF) and it may improve procedural effectiveness. However, there is no evidence evaluating efficiency, effectiveness, and safety outcomes of ICE in the context of the novel pulsed-field ablation (PFA) of AF. Purpose We aimed to evaluate the impact of ICE on procedural parameters in consecutive patients (pts) indicated for AF ablation with a new PFA technology. Methods All consecutive pts undergoing AF ablation with PFA at 5 experienced centers were included. Protocol-directed PVI was delivered using 2000 V with eight applications per vein, that is, four applications each in the basket and flower poses. Additional lesions were performed at the operator’s discretion. In procedures during which an ICE catheter was used, the ICE catheter was utilized to manipulate the PFA catheter in the left atrium to reach an optimal contact on the atrial structures. At the end of procedures, ICE was utilized for identification of procedure-related complications. Data are reported as median [IQ range]. Results One-hundred eighty pts were included in this analysis (36[32-40] pts per center; n=124, 69% paroxysmal AF; n=56, 31% persistent AF). The ICE-guided PFA procedures consisted of 35 (19.4%) cases. PVI was achieved in all pts with a 32[32-32.5] PFA applications per pt. Additional applications outside the PVs (i.e. posterior wall ablation) were performed in 31 (17%) cases, requiring 18[12.5-26] PFA deliveries on the lesion sets, all validated through 3D mapping and/or differential pacing. Fluoroscopy time was 17[13-22]min, LA dwell time was 22.5[18.5-27.5]min, skin-to-skin time was 60[52-80]min and total support time (procedural plus patient preparation) was 75[60-90]min. Considering PVI only cases, the use of ICE did not improve procedural metrics (ICE vs no ICE: 23[20-26]min vs 23[19-27]min for the time to PVI, p=0.4141; 65[64-85]min vs 70[60-82]min for support time, p=0.8271; 60[58-60]min vs 60[50-75]min for skin-to-skin time, p=0.8681 and 19[16-23]min vs 15[12-18]min for fluoroscopy time, p=0.0012). On the contrary, when looking at procedures with additional lesion sets, ICE-guided PFA showed some improvements (ICE vs no ICE: 27.5[25-30]min vs 16[13-20]min for the time to PVI, p=0.0003; 75[65-80]min vs 120[90-145]min for support time, p=0.0032; 70[60-74]min vs 82.5[74-112.5]min for skin-to-skin time, p=0.0077 and 20[16.5-22]min vs 20[17-30]min for fluoroscopy time, p=0.3328). No major procedure-related adverse events were reported. Conclusion In our preliminary experience, the use of a novel PFA system for AF ablation was safe and effective. The integration of ICE in guiding ablation, may provide some beneficial aspects, especially in the context of complex AF ablation with additional lesion sets.

Abstract Funding Acknowledgements Type of funding sources: None. Background Complete electrical pulmonary vein isolation (PVI) by thermal energy sources is a well-established ablation strategy of atrial fibrillation (AF). Recently, a non-thermal ablation approach by means of irreversible cellular electroporation has been made available for clinical use. Purpose We report the preliminary experience of a new pulsed-field ablation (PFA) system in the context of AF ablation in a multicenter Italian setting. Methods All consecutive patients (pts) undergoing AF ablation with PFA at 7 Italian centres were included. Protocol-directed PVI was delivered using 2000 V with eight applications per vein, that is, four applications each in the basket and flower poses. Applications were delivered in pairs at any given catheter position, rotating by ≈30–40° after the first two applications in each configuration. Additional lesions were performed at the operator’s discretion. The ablation endpoint was PVI as assessed by entrance and exit block. Data are reported as median [IQ range]. Results With a median of 32[25-38] pts treated per center, a total of 205 cases were included (n=150 73.2%, paroxysmal AF, n=55, 26.9% persistent AF). Of them 187 (91.2%) were de novo cases, whereas 18 (8.8%) were redo cases. A mapping system was used in 55 (21.5%) procedures and an intracardiac echocardiography in 65 (31.7%) cases. The number of PFA applications to reach PVI was 32[32-36]. Procedural parameters were: fluoroscopy time = 16[12-22] min, skin-to-skin time = 60[55-85] min, support time (preparation plus skin-to-skin) =75[64-95] min, lab occupancy time was 97[75-120] min and PFA LA dwell time was 23[20-28] min. The first pass isolation (FPI) rate per vein was 99.6% resulting from 202 patients (98.5%) with FPI. At the end of the procedure, PVI was achieved in all pts (100%) using only PFA. Additional PFA delivery outside PVs was performed in 19% (n=39) of the cases, mostly at the posterior wall area only (n=34, 87%), requiring 16[12-24] PFA deliveries. All the additional lesion sets were validated through differential pacing and/or 3D mapping. The learning curve was extremely fast. After only 5 cases time to PVI and total support time have significantly improved, whereas we did not notice any additional improvement after 10 or 20 cases (LA dwell time: 27[22-32] min during the first 5 cases vs 23[19-27] min after the first 5 cases, p=0.0172; support time: 100[65-120] min vs 75[65-90] min, p=0.0181, respectively). In 13 (6.3%) cases a transient bradycardia or asystole occurred after the first PFA application requiring temporary high-output pacing. No major procedure-related adverse events were reported. Conclusion In this first multicentric experience, the novel PFA system proved to be safe and effective in both paroxysmal and persistent AF patients. The learning curve seems to be very fast according with procedural parameters.