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Aims To evaluate the safety and effectiveness of a compliant multi-electrode radiofrequency balloon catheter (RFB) used with a multi-electrode diagnostic catheter for pulmonary vein isolation (PVI). Methods and results This prospective, multicentre, single-arm study was conducted at six European sites and enrolled patients with symptomatic paroxysmal atrial fibrillation. The primary effectiveness endpoint was entrance block in treated pulmonary veins (PVs) after adenosine/isoproterenol challenge. The primary safety endpoint was the occurrence of primary adverse events (PAEs) within 7 days. Cerebral magnetic resonance imaging and neurological assessments were performed pre- and post-ablation in a subset of patients. Atrial arrhythmia recurrence was assessed over 12 months via transtelephonic and Holter monitoring. Quality of life was assessed by the Atrial Fibrillation Effect on Quality of Life (AFEQT) questionnaire. Of 85 patients undergoing ablation per study protocol, PV entrance block was achieved in all (one PV required touch-up with a focal catheter). Acute reconnection of ≥1 PVs after adenosine/isoproterenol challenge was observed in 9.3% (30/324) of PVs ablated. Post-ablation, silent cerebral lesions were detected in 9.7% (3/31) of patients assessed, all of which was resolved at 1-month follow-up. One patient experienced a PAE (retroperitoneal bleed). Freedom from documented symptomatic and all arrhythmia was 72.2% and 65.8% at 12 months. Four patients (4.7%) underwent repeat ablation. Significant improvements in all AFEQT subscale scores were seen at 6 and 12 months. Conclusion PVI with the novel RFB demonstrated favourable safety and effectiveness, with low repeat ablation rate and clinically meaningful improvement in quality of life. ClinicalTrials.gov Registration Number NCT03437733., Graphical Abstract

ObjectivesAtrial fibrillation (AF) is the most common sustained cardiac arrhythmia associated with substantial morbidity and mortality. Data on long-term risk and mortality after catheter ablation for AF are lacking. The aim of this study was to evaluate all-cause mortality and the long-term risk of death in patients who underwent catheter ablation for AF compared with the general population.DesignRetrospective, population-based epidemiological study.SettingWe analysed data from patients residing in Apulia region who underwent AF ablation between January 2009 and June 2019.Participants1260 patients (914 male, mean age 60±11 years).OutcomesVital status and dates of death to 31 December 2019 were obtained by using regional Health Information System. The expected number of deaths was derived using mortality rates from the general regional population by considering age-specific and gender-specific death probability provided for each calendar year by the Italian National Institute of Statistics. Standardised mortality ratios (SMRs) were calculated by dividing the observed number of deaths among patients by the expected number of deaths estimated from the general population.ResultsDuring follow-up (6449 person-years), 95 deaths were observed (1.47 deaths per 100 person-years). Although overall long-term mortality after AF ablation was not different to that of the general population (SMR 1.05 (95% CI 0.86 to 1.28; p=0.658)), the number of observed events was significantly increased in patients with heart failure (HF) at baseline or who developed HF during follow-up (SMR 2.40 (1.69 to 3.41; pConclusionLong-term mortality of patients undergoing AF ablation is similar to that of the general population. Patients with HF had an increased risk while those without seem to have a better risk profile.

Linac‐based STereotactic Arrhythmia Radioablation (STAR) is a safety and effective approach for selected patients with ventricular arrhythmias.

Purpose: Approaching treatment for elderly patients with atrial fibrillation is difficult. A prospective phase II trial evaluating LINAC-based stereotactic arrhythmia radioablation (STAR) safety in this population started in 2021. Dosimetric and planning data were reported. Materials and Methods: A vac-lock bag was used for immobilization in the supine position and a computed tomography (CT, 1 mm) was performed. The clinical target volume (CTV) was defined as the area around the pulmonary veins. An internal target volume (ITV) was added to the CTV to compensate heart and respiratory movement. The planning target volume (PTV) was defined by adding 0–3 mm to the ITV. STAR was performed during free-breathing with a PTV prescription total dose (Dp) of 25 Gy/1 fraction. Flattening filter-free volumetric-modulated arc therapy plans were generated, optimized, and delivered by TrueBeamTM. Image-guided radiotherapy with cone-beam CT and surface-guided radiotherapy with Align-RT (Vision RT) were employed. Results: From May 2021 to March 2022, 10 elderly patients were treated. Mean CTVs, ITVs, and PTVs were 23.6 cc, 44.32 cc, and 62.9 cc, respectively; the mean prescription isodose level and D2% were 76.5% and 31.2 Gy, respectively. The average heart and left anterior descending artery (LAD) Dmean were 3.9 and 6.3 Gy, respectively; the mean Dmax for LAD, spinal cord, left and right bronchus, and esophagus were 11.2, 7.5, 14.3, 12.4, and 13.6 Gy, respectively. The overall treatment time (OTT) was 3 min. Conclusions: The data showed an optimal target coverage, sparing surrounding tissue, in 3 min of OTT. LINAC-based STAR for AF could represent a valid non-invasive alternative for elderly patients who were excluded from catheter ablation.

AIMS Atrial fibrillation (AF) has been highlighted as a growing epidemic. Evidence is lacking on the role of different risk factors within both genders especially in AF patients referred for catheter ablation (CA). The objective was the evaluation of differences between men and women in the associations with aging, obesity and hypertension as the most highly contributing factors to AF onset and progression. METHODS Cases selected among patients scheduled for CA as a rhythm-control strategy and controls from a recent Italian national survey on the population's health conditions were analysed to quantify the strength of association and to assess the existence of gender differences. To reduce the effect of possible confounding factors, both cases and controls were selected without preexisting comorbidities other than hypertension. RESULTS At multivariate logistic regression analysis, cases (534 patients, 166 women) were significantly associated with the male sex, higher age, presence of obesity and hypertension in comparison to controls (17,983 subjects, 9,409 women). At analyses gender-stratified, age and obesity had a significant greater association in women than men. On the contrary, hypertension was relatively more frequent in men than women. CONCLUSION Although mechanisms linking risk factors and AF are complex, this study suggests the existence of differences mediated by gender in AF drug-refractory patients who underwent CA. A tailored public health programme to reduce the growing burden of AF needs to be designed to prevent and counter the increasing epidemic of the most common cardiac arrhythmia as well as its progression in more resistant forms.

INTRODUCTION Catheter ablation is an important treatment option for sustained ventricular arrhythmias (VA) that are refractory to pharmacological treatment; however, patients with fast VA or electrical storm (ES) are at risk for cardiogenic shock. We report our experience using cardiopulmonary support with extracorporeal membrane oxygenation (ECMO) during catheter ablation of VA. METHODS Nineteen patients (mean age, 62 ± 10 years; 84% male) were referred to our center for CA of ES between January 2017 and April 2018. ES was defined as the occurrence of ≥3 ventricular tachycardia or ventricular fibrillation episodes requiring electrical cardioversion or defibrillation in a 24-hour period. ECMO support was implemented for all patients. RESULTS CA of ES was completed in all patients. Activation mapping was performed for all VTs and substrate modification was performed by targeting sites identified by late/fragmented abnormal potentials. VTs were not inducible after ablation in 16 of 19 patients (84%). With regard to procedural complications, two patients underwent percutaneous angioplasty with stenting for a femoral artery dissection and one patient was treated for a dislodged ECMO arterial cannula and subsequent hemorrhagic shock. After a median follow-up of 10 months, three patients died from refractory heart failure and one patient died as a result of ES. Overall, the procedural success rate was 68% and the Kaplan-Meier mortality rate was 21%. CONCLUSIONS ECMO support may be used for ablation procedures in patients with ES.

ObjectivesThe association between obesity and atrial fibrillation (AF) is well-established. We aimed to evaluate the impact of index body mass index (BMI) on AF recurrence at 12 months following catheter ablation using propensity-weighted analysis. In addition, periprocedural complications and fluoroscopy details were examined to assess overall safety in relationship to increasing BMI ranges.MethodsBaseline, periprocedural and follow-up data were collected on consecutive patients scheduled for AF ablation. There were no specific exclusion criteria. Patients were categorised according to baseline BMI in order to assess the outcomes for each category.ResultsAmong 3333 patients, 728 (21.8%) were classified as normal (BMI 2), 1537 (46.1%) as overweight (BMI 25.5–29.0 kg/m2) and 1068 (32.0%) as obese (BMI ≥30.0 kg/m2). Procedural duration and radiation dose were higher for overweight and obese patients compared with those with a normal BMI (p=0.002 and p2led to a 1.2-fold increased likelihood of experiencing recurrent AF at 12-months follow-up as compared with overweight patients (HR 1.223; 95% CI 1.047 to 1.429; p=0.011), while no significant correlation was found between overweight and normal BMI groups (HR 0.954; 95% CI 0.798 to 1.140; p=0.605) and obese versus normal BMI (HR 1.16; 95% CI 0.965 to 1.412; p=0.112).ConclusionsPatients with a baseline BMI ≥30 kg/m2have a higher recurrence rate of AF following catheter ablation and therefore lifestyle modification to target obesity preprocedure should be considered in these patients.

To analyze geometrical approaches, prescription modalities, and delivery efficiency for linear accelerator (Linac)-based STereotactic Arrhythmia Radioablation (STAR) for ventricular tachycardia. The anatomy and planning target volume (PTV) of the first Italian STAR patient were used. To assess geometrical approaches, 3 plans prescribed to 75% isodose-line, differing for number, length of arcs, and couch rotations, were generated and compared (Plans#1–3). Volumetric-arc with 6-MV flattening-filter-free (FFF) was employed. To evaluate prescription modality and delivery, the best geometrical plan was compared with other plans prescribed on 70%, 65%, and 60% isodose-line and with another one using 10MV-FFF beams (Plans#4–7). For Plans#1–3, PTV coverage, mean cardiac dose, monitor units (MUs), and beam-delivery-time (BDT) were 96–98.5%, 4.9–5.2 Gy, 7047–7790, and 5–6 min, respectively. Plans#4–7 were similar in terms of mean cardiac dose, MUs and BDT to Plans#1–3, except in maximum dose and lower time for 10MV-FFF plan. Linac-based STAR is safe and efficient in terms of BDT and MUs. To ensure high dose to PTV, different dose prescription modalities should be evaluated. The 10FFF approach was the faster but not suitable in patient with cardiac implantable electronic devices.

Aims Uninterrupted anticoagulation is recommended during the ablation of atrial fibrillation. This meta-analysis compared the safety and efficacy of uninterrupted direct oral anticoagulants (DOACs) to uninterrupted vitamin K antagonists (VKAs) during atrial fibrillation ablation. Methods The meta-analysis included eligible randomized controlled trials from 2009 to 2019. Odds ratios (ORs) and 95% confidence intervals were pooled using a random effects model and a sensitivity analysis was performed by sequentially removing one study or DOAC at a time. Results Six studies were included; 1288 received DOAC and 1081 VKA. Pooled ORs indicated a lower nonsignificant incidence in DOACs vs. VKA of composite outcome of major bleeding, stroke, or transient ischemic attack, and mortality (0.69; 0.28-1.71; 31 vs. 45 events), major bleeding alone (0.66; 0.30-1.47; 27 vs. 41 events), and cardiac tamponade (0.56; 0.21-1.45; eight vs. 13 events) with a slightly higher occurrence of minor bleeding (1.17; 0.89-1.56; 139 vs. 106 events) and silent cerebral thromboembolic events (1.12; 0.75-1.66; 72 vs. 58 among 442 and 376 patients performing MRI study). Sensitivity analyses confirmed overall results: pooled ORs ranged from 0.56 to 1.00 for the composite outcome and from 0.54 to 0.92 for major bleedings. Conclusion Uninterrupted DOAC is a safe and effective alternative to uninterrupted VKA during atrial fibrillation ablation.

Pulmonary vein isolation (PVI) is the cornerstone of catheter ablation in paroxysmal atrial fibrillation (PAF). Studies reported that the PVI single procedure was able to achieve durable sinus rhythm without the need of antiarrhythmic drugs in 60-80% of patients with PAF. In this study, we report data regarding bilateral left lateral ridge ablation for PAF.We retrospectively collected data of 120 consecutive patients (mean age 56 ± 10 years; 62% male) referred to our center to perform PVI. In 60 patients we performed PVI (group 1) and in 60 patients performed PVI and bilateral left lateral ridge ablation (group 2). All patients performed a clinical follow-up after 24 months from the ablation procedure.PVI was achieved in all patients. The mean radiofrequency time to perform ablation on the left atrial appendage ostium was 216 ± 49 s. In all patients of group 2 we obtained disappearance of local electrograms and the loss of local capture during pacing on posterior wall of left atrial appendage ridge. No significant differences were found between the two groups regarding mean contact force during ablation (14 ± 4 vs. 15 ± 4 g; groups 1 and 2, respectively, P = 0.34). At 24-month follow-up, single procedure success rate was significantly higher in group 2 compared with group 1 (88 vs. 74%, respectively; P = 0.03). No significant procedural complications were documented.Bilateral left lateral ridge ablation is a safe technique able to improve the success rate of PVI in patients with PAF.

The circular nMARQ ablation catheter is a useful tool for pulmonary vein isolation (PVI). Some studies reported a high incidence of esophageal lesions by using this catheter.The primary aim of this study was to compare the effects on the esophageal wall of bipolar and unipolar energy applied by the nMARQ ablation catheter during AF ablation.Forty patients (mean age 53 ± 8 years; 26 [65%] men) were enrolled to perform PVI for symptomatic atrial fibrillation. Thirty patients underwent PVI with the nMARQ catheter (group 1) and 10 patients with the ThermoCool Surround Flow catheter (group 2). The procedures were performed with the CARTO3 system. All patients received an esophageal temperature probe. In group 1, we delivered unipolar energy on the left posterior wall with power between 15 and 18 W or bipolar energy with power at 15 W. In group 2, unipolar energy was delivered on the posterior atrial wall at 20-25 W power. All patients underwent esophagoscopy the day after the procedure.No patients had procedural complications. In group 1, bipolar energy was associated with a lower esophageal temperature increase as compared with unipolar energy (0.6°C [range 0-2.2°C] vs 2.1°C [range 0.8-2.9°C]; P.001). Unipolar energy was associated with a similar temperature increase in the 2 groups (1.9°C [range 0.8-2.9°C] in group 1 vs 1.7°C [range 0.7-2.9°C] in group 2; P = .49). No patient had esophageal injury.The use of the nMARQ catheter for PVI is feasible and safe. The use of 15 W for bipolar energy or 15-18 W for unipolar energy is an optimal strategy to avoid esophageal injury with this new catheter.

The paper describes an experimental study on the heat transfer inside a wickless heat pipe. In a previous paper [1, 2] an experimental campaign was conducted to ascertain the influence of different filling ratio on the heat transfer. The experiment was made with tubes inclined at 45°. To evaluate the influence of the inclination respect to the horizontal on heat transfer, a new campaign was conducted with the tubes inclined at 30°, to compare the result with those ones obtained with the different inclination. For this purpose the same filling ratio used in the previous campaign was used. The heat pipe is made of copper, the length is 1420 mm, internal diameter is 6 mm, and the vacuum inside is 10-5 bar. The experimental campaign was conducted on the experimental facility named T.O.S.C.A. (Thermal-fluid dynamics Of Solar Cooling Apparatus), which has been designed and constructed to test the influence of various geometrical an thermo-hydraulic parameter on the performance of the wickless heat pipe. The facility was built in the “Thermal-Fluid Dynamics Applied to Energy Systems” laboratory of ENEA-Casaccia Research Centre (Rome), The cooling loop is constituted of a collector coupled with a pump, a dumper and a heat exchanger. Pressurized water flows inside the collector cooling the heat pipe. The condenser section of the heat pipe is immersed in the free stream of the water. The heat pipe is heated by a heater made with an electrical wire wrapped on a length of 85% of the total length. We apply an electrical power, of 70W and 155W, values that simulate the solar power. Flow rate and pressure of the cooling water are constant. We measured the wall temperature of the heat pipe in the three different zone of the heat pipe: evaporator, adiabatic part and condenser; two other thermocouple are inserted in the collector to measure the heat transfer using a power balance.