Abstract Background Pulmonary vein isolation (PVI) alone is often insufficient for catheter ablation (CA) of persistent atrial fibrillation (PerAF), and the benefit of additional left atrial posterior wall ablation (LAPWA) remains controversial. Purpose We investigated whether signals recorded with a pentaspline pulsed field ablation (PFA) catheter can identify PerAF patients with rapid LAPW activity who may benefit from LAPWA. Additionally, we evaluated whether PFA-induced atrial fibrillation cycle length (AF-CL) prolongation, measured from the coronary sinus (CS), predicts arrhythmia-free survival. Methods In this multicenter observational study, consecutive PerAF patients undergoing first-time ablation with a pentaspline PFA catheter were included. PVI and LAPWA were performed in all cases. AF-CL was measured using the FARS-10 method at three time points: baseline, post-PVI, and post-LAPWA, using distal CS signals. LAPW-CL was measured post-PVI from multiple LAPW positions, with the fastest value retained. Arrhythmic recurrence was defined as any atrial tachyarrhythmia (ATA) lasting >30 seconds beyond the 2-month blanking period. Results Among 270 included patients (mean age 67.1 ± 11.0 years; 29.6% female). Median AF duration was 12 [9-20] months. The overall 12-month ATA-free survival was 72.6%. "Fast LAPW activity" was defined as a LAPW-CL value shorter than the mean LAPW-CL of the entire cohort (191.4±2.4 msec; ≤ 190 msec). Fast LAPW activity was not associated with arrhythmia recurrence (OR 1.263, 95% CI: 0.739–2.160; p=0.393). In contrast, a greater CS-CL prolongation following PVI + LAPWA was independently associated with lower recurrence risk (OR for arrhythmia recurrence 0.298, 95% CI: 0.017–0.520; p<0.001). A CS-CL increase >23.5% from baseline had a sensitivity of 0.65 and specificity of 0.72 for predicting ATA-free survival. Conclusion Post-PVI fast LAPW activity does not predict recurrence after LAPWA in PerAF patients. However, a CS-CL prolongation >23.5% after LAPWA may serve as a useful real-time marker of effective substrate modification and arrhythmia control

Abstract Background pulsed-field ablation (PFA) technology offers a non-thermal approach that is potentially more selective and safer than traditional techniques, but the extent of lesions and the unintentional involvement of the left atrial (LA) posterior wall (PW) remains unclear. Purpose This study aimed to characterize PFA lesion formation following PVI in real-world atrial fibrillation (AF) patients using high-density (HD) voltage mapping. Moreover, this study explored whether unintentional PW involvement is associated with a higher risk of arrhythmias’ recurrence. Methods 113 patients were prospectively included and underwent PVI with the PFA Farapulse system with at 14 centers. Protocol-directed PVI was delivered using 2 kV with eight applications per vein with additional applications as needed to achieve PVI at operator’s discretion. After PVI, an HD 3-dimensional (3D) map of the LA was performed with the Rhythmia/Orion system (31%), Carto/Pentaray system (29.2%) or NavX/HD Grid system (39.8%) according to operator's choice. Bipolar voltage color display range was set to <0.5 mV to zones of low-voltage areas as either acute lesion formation or chronic scarring. After mapping the LA was segmented into 7 sectors around the right PVs and 7 sectors around the left PVs to enable structured regional analysis. In order to quantify lesion extension across the PW, we identified 9 predefined sectors divided into 3 segments: upper, intermediate and lower (see figure 1). Unintentional PW involvement was defined as involvement of at least 1 of the PW sectors: PW narrowing was defined when 2 sectors of the same segment and PW closure in case of 3 sectors of the same segment involved. Patients were followed for a median of 280 days to track arrhytmias’ recurrences. Results PVI was successfully achieved in all patients, with complete antral isolation in 100% of the cases. The mean ablated area around PVs was 34.3±5 cm2: 10.0±4 cm2 at the anterior portion of the PVs, 9.2±2 cm2 at the posterior site, 4.2±1 cm2 in the superior area, 3.9±1 cm2 in the inferior area and 5.3±2 cm2 at the carina region. Unintentional posterior wall involvement was observed in 63 (55.8%) of the patients, PW narrowing in 31 (27%) and PW closure in 8 (7%) following remapping. During follow-up, 10.4% experienced recurrent AF and 8.1% developed atrial tachycardia or flutter. No significant association was found between PW lesion involvement and arrhythmias’ recurrence. Conclusion PVI with the Farapulse system was achieved in all patients resulting in complete antral isolation of the PVs in 100% of the cases. PW involvement is not an infrequent finding at post-ablation high-density 3D mapping but does not engender a higher risk of arrhythmias’ recurrences. Larger prospective studies with longer follow-up periods are needed to further clarify the clinical implications of PW involvement.

There are limited effective treatment options for persistent atrial fibrillation (AF) patients, with pulmonary veins (PV) isolation alone being considered suboptimal for many patients. Hybrid convergent ablation has been shown to improve clinical outcomes when compared to an endocardial-only radiofrequency (RF) strategy. Pulsed field ablation (PFA) has recently gained growing interest for its efficacy and safety profile in PV and posterior wall (PW) ablation. This study aimed to compare the efficacy and safety of the hybrid-convergent RF vs PFA of PVs and LAPW in long-standing persistent atrial fibrillation (LSPAF) Ninety-three consecutive LSPAF patients, treated with 2-step hybrid-convergent RF ablation (hybrid group, n = 49) or with PFA of PVs and LAPW (PFA group, n = 44) were enrolled. Primary efficacy endpoint was defined as any atrial tachyarrhythmias (ATA) recurrence after the 3-month blanking period, over a follow-up time of 18 months. Periprocedural adverse events and late complications during follow-up were deemed primary safety outcomes. PV and LAPW ablation were acutely successful in all patients. The hybrid and PFA groups had similar baseline characteristics: no differences were found between PFA and Hybrid groups regarding age (PFA 66.0±7.4 years vs Hybrid 63.9±10.6 years; p=0.193) and left atrial volume index (PFA 45.5 [36.7-57.2] ml/m2 vs Hybrid 45.0 [39.2-59.7] ml/m2; p=0.920). There were no significant differences regarding AF duration (PFA 38.0 months [IQR: 19.2 to 99.0 months] vs Hybrid 70.0 months [IQR: 46.0 to 118.0 months]; p = 0.063). Redo ablation patients’ rate was higher in the hybrid group (PFA n=16, 36.4% vs Hybrid n=28, 66.6%; p<0.001). Differences regarding left ventricular ejection fraction were borderline significant among groups (PFA 55.0 [49.5- 62.0] % vs Hybrid 60.5 [52.3-65.0] %; p=0.048), both showing an overall normal LV function. Step 1 hybrid-epicardial procedures were longer than PFA (166 [Q1-Q3: 140-205] minutes vs 107.5 [Q1-Q3: 82.5-12] minutes; P < 0.01). After a median follow-up of 615.5 [498–750] days, there was no difference in ATA recurrences between groups (Hybrid 52,3 % vs PFA 44,1 %; P = 0.450); no difference in the antiarrhythmic drug use rate was found (PFA n=24, 54.5% vs Hybrid n=19, 45.2%; p=0.388). PFA showed a better safety profile with a lower rate of major periprocedural complications compared with hybrid ablation (12% vs 0%; P = 0.028). Hybrid-convergent and PFA PVI and PW ablation share 18 months comparable arrhythmic outcomes in LSPAF, with PFA of PV and PW being an endocardial-only, less invasive and faster procedure.

Catheter ablation (CA) for the treatment of persistent atrial fibrillation (PersAF) represents a challenge since the outcome of pulmonary vein isolation (PVI) in this population is poor. The use of a pentaspline pulsed field ablation (PFA) catheter to target PV and left atrial (LA) posterior wall (LAPW) to treat PersAF has already been described. We aimed to determine if the extension of the LA ablation area beyond PV and LAPW is associated with improved rhythm outcome in PersAF patients. Consecutive PersAF patients undergoing CA with PFA were enrolled. Ablation strategy was chosen according to operators' preference. All patients received post-ablation high density voltage mapping for validation. Primary efficacy endpoint was defined as any atrial tachyarrhythmias (ATAs) recurrence after the 2-month blanking period. Periprocedural adverse events were recorded as the primary safety endpoint. One hundred eleven (n=111) consecutive PersAF patients, treated with PFA of PVs and LAPW (Box-only group [BO], n = 51) or with extensive PFA of the LA (Debulking group [DB], n = 60) were enrolled. Patients in the DB group were younger (64.7±8.0 years) than patients in the BO group (68.0±7.8 years, p=0.014). Echocardiografic baseline characteristics were similar (LA volume was: DB group 99.6±28.3 ml vs BO 96.2±35.3 ml; p=0.459; left ventricular ejection fraction was: DB group 57.5% [Q1-Q3: 52.7-62.9] vs BO group 55.0 % [Q1-Q3: 52.7-62.9]; p=0.459). DB group patients had shorter PersAF duration (DB group 24 months [Q1-Q3: 12.0-48.5] vs BO group 26.0 months [Q1-Q3: 15.0-54.0], p=0.014). Patients in the BO group received PVI and LAPW ablation (area from the upper end of the superior PV to the lower end of the inferior PV). All patients in the DB group received adjuntive ablation of the inferior wall towards the atrioventricular groove; among those, 44 patients underwent anterior roof ablation. Among these latter 44 patients, in 5 cases the lesion set was extended to the mitral isthmus, and in 2 cases to the posterior interatrial septum. There was no difference in the overall procedure duration (DB group 90 [Q1-Q3: 90-120] minutes vs BO group 95 [Q1-Q3: 87.5-120] minutes; p=0.849.) No differences in major periprocedural complications were recorded in both groups (one case of severe pericardial effusion plus one case of severe anemia due to hemolysis in DB group vs one major vascular access complication in BO group; p=0.465). After a median follow up of 411 days, patients in the DB group were less likely to show ATAs recurrences (recurrence rate DB group 23% vs BO 41%; p=0.044). No differences in the antiarrhytmic drug use rate was found between patients with recurrences (78.8% in DB group vs 71.4% in BO group, p=0.635). PVI plus extensive left atrial debulking showed better rhythm outcome compared to a PVI plus LAPW ablation in PersAF patients. No differences in periprocedural complications was found among groups.examples of post-CA voltage mapping

Increased left atrial (LA) size in atrial fibrillation (AF) is associated with AF recurrence following ablation. Limited data exist on pulsed-field ablation (PFA) in patients with persistent atrial fibrillation and dilated LA. We aimed to analyze the efficacy and safety of PFA in patients with severe LA dilatation (SLAD) (≥50 ml/m2) compared to normal to moderate LA dilatation (NMLAD) (<50 ml/m2) and persistent AF. All consecutive patients undergoing AF ablation with the Farapulse system at 14 centers with complete information of left atrial volume index (LAVi) were included. Protocol-directed PVI was delivered using 2 kV with eight applications per vein. Additional lesions were performed at the operator’s discretion. 197 patients with a history of persistent AF and were included in the analysis. Of these, 74 (37.6%) had long-standing persistent AF, 47 (23.9%) were female, the mean age was 65±8 years and the mean LVEF was 54±9%. The mean LAVi was 42.8±14 ml/m2, 51 (25.9%) patients showed SLAD. A 3D mapping system was used in 70 (35.5%) of the cases, a more extensive lesion set than PVI was performed in 157 (79.7%) of cases. Patients with SLAD exhibited a lower LVEF (50±10% vs 56±8%, p=0.0001) and had a higher burden of comorbidities (structural heart disease: 23.5% vs 9.6%, p=0.016; coronary artery disease: 31.4% vs 12.3%, p=0.004; chronic kidney disease: 9.8% vs 2.1%, p=0.028). No differences between groups were found in terms of underlying AF type (long-standing AF: 37.3% vs 37.7%, p=1.00), more extensive lesion set than PVI only (82.4% vs 78.8%, p=0.688) and the use of 3D mapping system (43.1% vs 32.9%, p=0.234). No differences were also found between groups in terms of PFA deliveries outside PVs (19[14-26] vs 18[14-22], p=0.324) or total number of PFA deliveries (52[46-66] vs 49[44-57], p=0.0616), whereas skin-to-skin time (84[61-95] min vs 70[55-85] min, p=0.004) and fluoroscopy time was longer (23[15-31] min vs 17[14-23] min, p=0.001) in patients with SLAD. PVI was achieved in all patients. During a median follow-up of 358[196-402] days, 34 (17.3%) of patients experienced an arrhythmic recurrence after the 90-day blanking period. The proportion of patient with SLAD who experienced a recurrence was similar to the ones with NMLAD (15.7% for SLAD vs 17.8% for NMLAD, p=0.831); increased LA size (continuous LAVi values or LAVi ≥ 50 ml/m2) was not associated to recurrences (hazard ratio=1.09, 95%CI: 0.98 to 1.03, p=0.945 for continuous LAVi values; 0.82, 0.34 to 1.79, p=0.612 for LAVi ≥ 50 ml/m2). No major complications occurred in both groups. In our experience, the use of Farapulse PFA system for persistent AF ablation in patients with severe LA dilatation demonstrated safe and effective outcomes, mirroring a comparable pattern observed in patient with normal to moderate LA size.

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 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 Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia. Clinical predictors such as persistent AF, increased left atrial volume and metabolic syndrome have been demonstrated to be associated with AF recurrence after ablation procedure (ATC). However, the impact of coronary heart disease (especially subclinical) and revascularization procedures on the outcome of rhythm control after ATC has not been extensively investigated. Purpose Aim of the study is to retrospectively evaluate the incidence of subclinical CAD in a population of patients with Atrial Fibrillation (AF) that underwent CT examination for left atrium and pulmonary veins assessment for ablation procedure planning and its correlation with post procedural AF recurrency. Methods 327 patients that underwent CT for left atrium and pulmonary veins for ablation procedure planning with post procedural clinical follow up were enrolled. Patients were divided into 2 groups (Group 1: known CAD / previous revascularization procedure, and Group 2: no history of CAD). CT exams of Group 2 patients were retrospectively evaluated to assess the presence of subclinical CAD. No quantification of coronary stenosis was performed. The correlation between clinical / procedural outcome and AF recurrence in the two groups during a mean follow up time of about 3 years, 2 years, 1 year and 6 months was compared by Kaplan-Meier curves. Results 51 patients had known history of CAD (Group 1). 269 patients had no history of CAD (Group 2). In group 2 CT revision showed the presence of subclinical CAD in 121 pts (45%). Overall AF recurrency after ATC was recorded in 17 out of 51 patients of group 1 (33%) and in 74 out of 269 patients (28%) of group 2. In group 2 CT showed coronary atheromatosis in 121 pts. Kaplan-Meier curves showed no significant differences in AF recurrency between Group 1 and Group 2 during all followup ranges. In Group 2 a higher AF recurrency rate in patients with CT positive for subclinical CAD during a mean follow up period of 2 years (p 0.015) was showed by Kaplan-meier analysis while slighty significant recurrency was observed during a 1 year followup (p 0.043). Not significant recurrency rate was observed during the 6 months follow up nor in longer follow up. Moreover in group 2 patients recurrency rate was significantly correlated to use of β-blockers during a 2 yy follow-up. Conclusions In patients without known history of CAD, the presence of subclinical CAD was associated with higher rate of AF recurrency during a mean follow up of both 1 and 2 years after ablation procedure. Detection of subclinical CAD in patients undergoing ATC has potential clinical indications for cardiac arrhythmia management and support the potential role of cardiac CT before procedural planning in the downstrem management of patients without history of CAD.

Abstract Background Head-to-head comparisons between stand-alone left atrial appendage closure (LAAC) and a same-procedure LACC + cryoballoon (CB) pulmonary vein isolation (PVI) (combined procedure) are currently lacking. Purpose To compare acute and long-term outcomes between stand-alone LAAC vs a LAAC+CB-PVI combined procedure. Methods All patients undergoing LAAC at our institution, having at least 2 years follow-up, were analyzed to assess the impact of additional CB-PVI. The primary efficacy and safety endpoints of our study were the acute procedural success rate and the peri-procedural complications rate. As secondary endpoints, major bleeding, and ischemic events, as well as sinus rhythm rate at 2 years follow-up were assessed. Results Among 126 LAAC patients meeting inclusion criteria (males=64.2%), n=55 (43.7%) underwent a combined procedure. LAAC-only patients were older (72.5±7.2 vs 68.9±8.6, p<0.05) and less frequently having paroxysmal AF (23.9% vs 47.3%, p<0.05). Baseline CHA2DS2-VASc was similar among groups (3.3±1.3 vs 2.9±1.1, p=0.07) while LAAC-only patients had higher HAS-BLED at enrollment (3.4±1.1 vs 3.0±1.0, p=0.04). Additional CB-PVI was not a risk factor for incomplete LAA occlusion (OR 0.24–3.78, p=0.96), presence of residual lateral flow (OR 0.26–4.05; p=0.96), intraprocedural need for occluder device resizing compared to pre-procedural assessment (OR 0.27–3.05; p=0.884), and peri-procedural complications (OR 0.25–6.74, p=0.749). At 3-month post-procedural trans-esophageal echocardiography, a combined procedure was not associated with higher risk of incomplete occlusion (OR 0.33–1.59, p = 0.432), nor larger peri-device leakages (coefficient k: -0.65–+0.20, p=0.291). Overall and by-group ischemic (red) and bleeding (blue) relative risk reduction from CHA2DS2-VASc and HAS-BLED predicted yearly rates during follow-up was reported in Figure1. Over a median follow-up of 40 [26–56] months, a combined procedure was not a risk factor for major bleeding (OR 0.31–5.48, p=0.715) or ischemic (OR 0.11–3.56, p=0.599) events. As expected, additional CB-PVI was strongly associated with a reduction of AF recurrences (OR 0.16–0.86, p<0.05), after excluding permanent AF patients from the analysis. Conclusion Combined LAAC + CB-PVI procedure does not appear to be a risk factor for worse LAAC-related outcomes, while reducing AF recurrences in non-permanent AF patients.Figure 1

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.

Abstract Funding Acknowledgements Type of funding sources: None. Background Previous studies have demonstrated that cardiac biomarkers elevate after both cryoballoon (CB) and radiofrequency atrial fibrillation (AF) ablation, depending on the amount of energy delivered and the site of ablation. To date no comparison has been made between these thermal energy source and a novel non-thermal pulsed-field ablation (PFA) technology based on cells electroporation. Purpose Our analysis aims to compare acute myocardial injury through cardiac troponin I variation after pulmonary vein isolation (PVI) performed with different technologies (PFA vs CB). Methods All consecutive patients undergoing paroxysmal AF ablation with CB and PFA at our center from July to November 2022 were included. Protocol-directed cryoablation (CBA) was delivered for 180 sec or 240 sec according to operator’s preference for isolation achieved in ≤60 sec, or 240 sec if isolation occurred >60 sec or when time to isolation was not available. A standard PFA protocol-directed PVI was applied using 2kV with eight applications per vein (four applications each in the basket and flower poses). The ablation endpoint was PVI as assessed by entrance and exit block. Pre- and post-procedure samples of cardiac troponin I (CTpI) were collected before CBA/PFA and at 24h after ablation. Only patients with normal baseline values for myocardial injury were included. Results A total of 71 patients met inclusion criteria and were included in this analysis. The CBA group consists of 50 (70%) patients and the PFA group comprises 21 (30%) patients. The number of CBA applications to reach PVI was 5.0±1.4 and the number of PFA applications to achieve PVI was 32±4. All (100%) patients were in sinus rhythm at the time of the procedure. Evaluating the kinetic of CTpI, baseline values were homogeneous between CBA and PFA groups (p=0.979) whereas CTpI values significantly rose from baseline (7±2 ng/L) to 24h (8979±3691 ng/L, p<0.0001) and were significantly different between groups after CBA/PFA (8148±3311 ng/L for CBA vs 11900±7143 ng/L for PFA, p=0.0056). PVI was achieved in all patients (100%) using only CB or PFA. No major procedure-related adverse events were reported. Conclusion Our preliminary results showed that cardiac troponin I enzyme level increased after PVI by means of both cryoballoon and pulsed-field ablation and were higher after cellular electroporation by PFA than cryoablation.

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Pulsed-field ablation (PFA) is a new non-thermal, tissue-specific ablation technique. Through the application of a local electric field, it is possible to induce a selective electroporation of cardiomyocytes membranes, resulting in myocytic apoptosis and sparing of non-myocardial structures (nerves, connective tissue, esophagus, vessels). Purpose A new PFA system for atrial fibrillation (AF) ablation has recently been introduced in our hospital. The aim of this retrospective review is to share the initial results of our experience in terms of acute efficacy and safety. Methods A total of 41 adult patients suitable for AF percutaneous ablation underwent PFA between April and November 2022 in our Institute. PFA system consisted of a current generator, a deflectable sheath and a multielectrode PFA catheter. Once inside the left atrium (LA), the PFA catheter was directed to the pulmonary veins (PVs) ostia through an over-the-wire system. Then, 8 electric impulses were applied for each PV to achieve electrical isolation; in some cases, applications to the posterior left atrium wall (LAPW) were delivered to obtain LAPW isolation (LAPWI). A moderate-to-deep sedation was provided by an anesthesiologist during all the procedures. Acute ablation efficacy was defined as absence of intracavitary signals at the electroanatomic mapping and local capture failure at the pacing maneuvers. Intra and peri-procedural safety was defined as the absence of major complications (pericardial effusion/ tamponade, stroke, vascular complications, death) during the procedure and the hospitalization period. Results Of the 41 patients included, 24 (58.5%) were treated for paroxysmal AF and 17 (41.5%) for persistent AF. In almost all cases (n=40, 97.6%) pulmonary veins isolation (PVI) was performed; in 14 cases (34.1%, almost all persistent AF patients) a LAPWI was performed with the application of a variable number of pulses (mean value = 13). In most of the cases (n=28, 68.3%) an electroanatomic mapping was acquired before and after the ablation. Acute efficacy was observed in all PVI cases (n=40, 100%) and in all LAPWI cases (n=14, 100%). No periprocedural major complications were observed (n=0, 0%). Conclusions PFA is a promising ablation technique capable of inducing selective myocytic apoptosis through electroporation, causing a thick damage across the muscle with no injury of other tissues, and could become a game changer in electrophysiology in the next future. Our initial data report a combination of ease of use and high efficacy and safety profiles.

Abstract A 22–year–old healthy athlete was referred to our hospital for electrocardiographic findings consistent with intermittent type–1 Brugada pattern. A routine electrocardiogram (ECG) performed during a check–up showed sinus rhythm, normal PR interval and QRS duration, rSR’ with a coved type ST–segment elevation in V2 lead (Figure 1).The patients denied history of syncope or palpitations and his family history did not show sudden cardiac death or Brugada syndrome (BrS). Transthoracic echocardiography was normal and a 12–lead Holter monitoring revealed the intermittence of the type–1 Brugada pattern. The patient was hospitalized for further investigation. On admission, ECG showed a type–2 Brugada pattern; therefore, Ajmaline challenge test (1 mg/kg injection in 10 minutes) was performed and resulted positive. Subsequently, the patient underwent an electrophysiological study (EPS) which was negative for induction of sustained arrhythmias. The protocol adopted consisted of double extrastimuli programmed electrical stimulation until refractoriness (drive 600/220 ms and 400/210 ms), at double sites (right ventricle apex and right ventricular outflow tract). Furthermore a genetic test was performed using next–generation sequencing, showing a heterozygous mutation in the SCN5A gene, encoding for sodium channel alpha subunit (variant c.5363delA), not previously described in the literature. Since the low arrhythmic risk, the patient was implanted with a loop recorder (ILR, Medtronic Reveal LINQ), entering a program of home monitoring. After a 15–months follow–up, an episode of ventricular polymorphic tachycardia lasting 2 minutes and 11 seconds, associated with lightheadedness and palpitations, was detected by the remote monitoring (Figure 2). The patient was therefore hospitalized. During the in–hospital stay a cardiac magnetic resonance was performed to exclude other underlying diseases, identifying an enlarged right ventricle (EDVi 114 ml/m2) and abnormal free wall motion (Figure 3), thus reaching one major criteria of arrhythmogenic cardiomyopathy (however not sufficient for the diagnosis). The patient was then implanted with a subcutaneous implantable cardiac defibrillator (Boston Scientific EMBLEM MRI S–ICD). We presented a case of complex arrhythmic risk stratification in a possible overlap of an arrhythmogenic cardiomyopathy and a Brugada Syndrome in a young athlete who experienced a sustained ventricular tachycardia during loop–recorder monitoring.

Abstract A 68 year–old male presented to the Emergency Department of our Institute with palpitations for the last 20 minutes. The patient suffered from Becker’s muscular dystrophy (BMD) with hypotonic tetraparesis and dilated cardiomyopathy with moderate left ventricular dysfunction. The patient had also arterial hypertension and a previous ischemic stroke treated with thrombolysis and subsequently with warfarin. On the admission, the patient was alert, blood pressure was 90/60 mmHg and heart rate 180 bpm. An ECG (Fig. 1) showed regular, wide–complex tachycardia (QRS duration of 240 msec) with right branch block morphology with left axial deviation. A bolus of amiodarone 200 mg ev was administered without efficacy followed by a bolus of lidocaine 50 mg. The patient developed symptomatic hypotension, so external electrical cardioversion was performed with a single DC shock at 200J, effective in restoring sinus rhythm. Amiodarone and beta blocker therapy was started. On laboratory tests, the main values were normal, including the ultrasensitive troponin hs–cTnI. Echocardiography showed a mildly dilated left ventricle with diffuse hypokinesia conditioning severe reduction of systolic function (FE 35%) (Fig. 2). On subsequent telemetric ECG monitoring, no recurrences of sustained ventricular tachycardia (VT) were recorded, but it was observed an episode of complete atrioventricular (AV) block conditioning a symptomatic 9.5–second asystole, treated with atropine. Then the patient underwent CRT–D implantation in secondary prevention. The day after the procedure, an arrhythmic storm occurred and was effectively treated with multiple attempts of antitachycardia pacing and device shock. In the following days, the patient continued to present with episodes of VT despite antiarrhythmic drugs. Hence, an endo–epicardial ablation of the arrhythmic substrate was evaluated in Heart team. In view of an intubation and the high anesthesiological risk, it was indicated to continue the optimized medical therapy. Mexiletine 200 mg tid was added to metoprolol 100 mg bid and amiodarone 200 mg od. In the following days, no arrhythmic recurrences were recorded on continuous ECG monitoring. The patient was discharged from the hospital asymptomatic and with no sign of heart failure. At 2 years of follow–up, the patient remained asymptomatic, with no arrhythmic events recorded by the device and in the absence of any adverse effects caused by mexiletine.

Background: Peripartum cardiomyopathy (PPCM) is a rare cardiomyopathy with systolic dysfunction that presents in late pregnancy. A number of coronavirus disease 19 (COVID-19)-related myocarditis cases have been reported. In a pandemic situation, the coexistence of COVID-19 and PPCM can be relatively frequent, making it difficult to assess the weight of the individual components on the heart condition. Case Presentation: A 34-year-old girl develops COVID-19 at the 31st week of pregnancy. In the following 2 weeks she recovered and, after 4 days from the disappearance of symptoms, she gave birth without complications. Three weeks after delivery she presented to the ED with worsening dyspnea and elevated troponine and BNP values. Echocardiogram showed severe biventricular systolic dysfunction, mitral regurgitation, pulmonary hypertension and biventricular thrombosis. She was treated with oxygen, diuretics, heparin and transferred to our center. Cardiac MRI showed dilation and severe biventricular dysfunction with positive LGE and T1 mapping values diffusely increased. A treatment with betablockers, Sacubitril/valsartan, anti-aldosterone drugs, ivabradine and bromocriptine was started. An Endomyocardial biopsy (EMB) was performed showing a picture consistent with dilated cardiomyopathy and a final diagnosis of peripartum cardiomyopathy was made. However, after a few days the molecular biology report arrived showing EMB positivity for Sars-Cov-2 and Parvovirus B19. The patient was discharged and after 6 months she is well and a control MRI showed complete recovery of biventricular systolic function. Discussion: Cardiovascular complications of COVID-19 are well known and cases of related myocarditis have been reported. Anatomopathological and biopsy studies show the presence of Sars-Cov-2 in the heart of a significant number of patients with COVID-19, however the virus is often found at the interstitial level, suggesting in most cases more an endothelial localization than a real invasiveness of cardiomyocytes. It is not impossible that a patient with PPCM could be simultaneously affected by Sars-Cov-2. Only a multidisciplinary clinical, imaging, histological, functional evaluation and a congruent follow-up can help to understand the weight of the single etiological components on cardiac dysfunction. Conclusions: We described a case of a patient with PPCM and concomitant cardiac localization of COVID-19 with severe acute biventricular dysfunction. (Figure Presented).

Abstract Funding Acknowledgements Type of funding sources: None. Background Complete electrical pulmonary vein isolation (PVI) by cryo-balloon approach is a well-established ablation strategy of atrial fibrillation (AF). Recently, a new cryoablation system (POLARx) with unique features has been made available for clinical use. To date, no data exist on procedural characteristics of this system in a multicentric clinical practice. Purpose We aimed to characterize the initial experience of this technology in the Italian clinical practice. Methods Consecutive patients (pts) undergoing AF ablation from the CHARISMA registry at 5 Italian centres were included. Protocol-directed cryoablation was delivered for 180 sec or 240 sec according to operator’s preference for isolation achieved in ≤60 sec, or 240 sec if isolation occurred >60 sec or when time to isolation (TTI) was not available. The ablation endpoint was PV isolation as assessed by entrance and exit block. Results Two-hundred sixty-two cryoapplications from 49 pts (194 PVs) were analyzed. PVI was achieved with cryoablation only in all pts. The mean number of freeze applications per pt was 5.3 ± 1.5 (1.3 ± 0.6 for LIPV, LSPV and RSPV, 1.6 ± 1.3 for RIPV), with 143 (73.7%) PVs treated in a single-shot fashion (38, 19.6% with 2 shots; 13, 6.7% with more than 2 shots). Sixteen (33%) pts were treated with a single freeze to each of the PVs. The mean nadir temperature was -55.5 ± 6.9 °C and was colder than -50°C in 83% of the PVs. TTI information was evaluable in 120 (46%) cryoapplications with a median TTI of 47 [32-75] sec (median temperature at TTI = -49 [-53 to -42] °C). The mean time to target -40 °C (TTT) was 30.1 ± 6.9 sec with a TTT < 60 sec achieved in 99.2% of the cryoapplications; the mean thaw time to 0 °C was 18.6 ± 5.8 sec (thaw time >15 sec in 70.3% of the cryoapplications). The mean PV occlusion grade (rank 1-4) was 3.6 ± 0.6 (grade 2 in 5.2% of the cases, grade 3 in 25.6% and grade 4 in 69.2%). No complications were observed at 30 days post-procedure. Conclusion In this first multicentric experience in a clinical practice setting, the novel cryo-balloon system proved to be safe and effective and resulted in a high proportion of successful single-freeze isolation. Cooling parameters seem to be slightly different from reference cryo-balloon technology.

Background Ventricular tachycardia (VT) is a life-threatening condition, which usually implies the need of an implantable cardioverter defibrillator in combination with antiarrhythmic drugs and catheter ablation. Stereotactic body radiotherapy (SBRT) represents a common form of therapy in oncology, which has emerged as a well-tolerated and promising alternative option for the treatment of refractory VT in patients with structural heart disease. Objective In the STRA-MI-VT trial, we will investigate as primary endpoints safety and efficacy of SBRT for the treatment of recurrent VT in patients not eligible for catheter ablation. Secondary aim will be to evaluate SBRT effects on global mortality, changes in heart function, and in the quality of life during follow-up. Methods This is a spontaneous, prospective, experimental (phase Ib/II), open-label study (NCT04066517); 15 patients with structural heart disease and intractable VT will be enrolled within a 2-year period. Advanced multimodal cardiac imaging preceding chest CT-simulation will serve to elaborate the treatment plan on different linear accelerators with target and organs-at-risk definition. SBRT will consist in a single radioablation session of 25 Gy. Follow-up will last up to 12 months. Conclusions We test the hypothesis that SBRT reduces the VT burden in a safe and effective way, leading to an improvement in quality of life and survival. If the results will be favorable, radioablation will turn into a potential alternative option for selected patients with an indication to VT ablation, based on the opportunity to treat ventricular arrhythmogenic substrates in a convenient and less-invasive manner.

Abstract Background Current arrhythmogenic right ventricular cardiomyopathy (ARVC) diagnostic criteria are mostly based on ventricle function and dimension. Previous studies have reported a significant overlap between ARVC and chronic myocarditis, at non-invasive assessment. Purpose Tto compare biopsy-proven ARVC and myocarditis patients, in order to identify clinical, imaging and invasive electroanatomic voltage mapping (EVM) differences between the two groups. Methods Patients with borderline diagnosis of ARVC or suspected myocarditis underwent compete assessment with cardiac magnetic resonance (CMR). All patients underwent endomyocardial biopsy (EMB) with targeted tissue sampling guided by EVM. All patients with an histological diagnosis of myocarditis or ARVC were included. Results 83 patients were included, divided into 35 (42.2%) ARVC and 48 (57.8%) myocarditis. Among ARVC patients, 25 (71.4%) had right dominant ARVC, 5 (14.3%) left dominant patter and 5 (14.3%) bi-ventricular involvement. Nine patients (23.1%) with suspected clinic diagnosis of ARVC before EMB, received and histological diagnosis of myocarditis. Two (5.7%) patients with suspected myocarditis were proven to have ARVC. When comparing patients with ARVC and patients with myocarditis, univariate analysis showed that age, sex, family history, arrhythmic disorders at presentation and ECG abnormalities were similar between the two groups (P>0.05 for all the variables). There was also no significant difference with regards to bi-ventricular function and dimension at CMR evaluation. More patients with myocarditis resulted positive at late gadolinium enhancement (LGE) evaluation, although non-significantly (P=0.082). Oedema was more frequently present in patients with myocarditis (P=0.01), while adipose tissue infiltration and segmental wall motion abnormalities were more often observed in patients with ARVC (P=0.002 and P<0.001 respectively). At EVM analysis, a significant greater number of patients had a pathological uni- and bi-polar EVM (P<0.05 in all cases) and the scar-area was greater in patients with ARVC: 18.8 vs 11.0 cmq (P=0.041). Conclusion(s) A significant number of patients who received a clinical diagnosis of Myocarditis or ARVC according to current guidelines, were subsequently reclassified after histological analysis. Patients with ARVC and myocarditis were not distinguishable on the basis of clinical features and ventricular function and dimensions. Conversely, tissue analysis with CMR demonstrated how patient with ARVC had less oedema, more adipose tissue infiltration and had more extensive scar at EVM evaluation. Funding Acknowledgement Type of funding source: None

Introduction. Few data exist about effectiveness of atrial fibrillation (AF) catheter ablation (CA) in athletes and feasibility of resuming vigorous exercise afterwards. Aims of our study were to analyze the efficacy and safety of AF CA in athletes, to compare AF CA outcomes in athletes vs Non-Athletes (NA) and to evaluate the feasibility of resuming vigorous exercise. We additionally analyze the outcome of patients that underwent concomitant cavo-tricuspid isthmus (CTI) CA. Methods and results. From January 2015 to October 2019, 38 athletes were retrospectively matched with 38 NA that underwent first time AF CA. After a median follow-up of 787 days, 62.5% of athletes were free from recurrences after one CA procedure and mostly without antiarrhythmic drugs (87%). Seven athletes underwent a redo procedure and all of them were then free of recurrences with an overall freedom from recurrences of 84%. No major complications were observed. After the first year of follow-up, athletes had a 48% reduced risk of recurrences than NA [adjusted hazard ratio (HR) on antiarrhythmic drugs, LA volume and AF subtype, HR 0.52]. Athletes that underwent also CTI ablation showed a positive trend in terms of freedom from recurrences (50% vs 21%). Most (72%) of the athletes resumed vigorous exercise after at least 3 months from the CA. Conclusion. AF CA is a safe and efficient therapeutic option in athletes and it should be considered instead of drugs to early resume competitive sport activity. Concomitant CTI ablation may have a favorable role.

Abstract Background The diagnosis of concealed cardiomyopathies in patients with ventricular arrhythmias (VAs) is one of the major challenging issues faced by physicians. Purpose We aimed at reporting the cardiomyopathic substrate in patients with recurrent arrhythmias of ventricular origin. Methods Consecutive patients with unexplained VAs underwent a complete diagnostic work-out, including endomyocardial biopsy (EMB). Results Ninety-seven patients were enrolled (76.3% male, age 39.7±13.3 yrs). The presenting arrhythmic manifestation was aborted cardiac arrest in 30 (30.9%) patients, sustained ventricular tachycardia (VT) in 9 (9.3%), nonsustained VT in 15 (15.5%) and frequent premature ventricular complexes in 43 (44.3%). Overall, 350 biopsies were collected (3.6/patient). The incidence of procedure-related complications was 5.1% (n=5): 4 major complications (1 rupture of a tricuspid chorda tendinea w/o hemodynamic impairment, 1 dissection of right external iliac artery treated with stent, 1 thrombotic occlusion of left superficial femoral artery which required surgical treatment, 1 TIA) and 1 minor complication (groin hematoma) occurred. The final diagnosis was arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) (n=41; 42.3%), followed by myocarditis (n=20; 20.6%), dilated cardiomyopathy (n=6; 6.2%), cardiac sarcoidosis (n=6; 6.2%), and myocarditis in ARVD/C (n=5; 5.1%). Among the 25 patients whose final diagnosis was consistent with myocarditis, an acute stage of the disease was documented in 7 (7.2%), while a chronic myocarditis in 18 (18.5%). Additionally, according to medical history and diagnostic workout, in 2 of the 6 patients the dilated cardiomyopathy had a likely post-inflammatory etiology. Absence of myocardial abnormalities was documented in 15 (15.5%) patients: this group included 1 case of methadone-induced torsade de pointes. The remaining 4 (4.1%) patients were diagnosed with a cardiac hypertrophy (n=2, 2.1%, secondary to exercise or Fabry disease), a dilated mitochondrial cardiomyopathy (n=1, 1.0%), a dilated cardiomyopathy in Emery-Dreifuss muscular dystrophy (n=1; 1.0%). Conclusion In our series, approximately 45% of patients with unexplained VAs had a final diagnosis of ARVD/C.