Genetic Testing in Brugada Syndrome: A 30-Year Experience.

BACKGROUND: A pathogenic/likely pathogenic variant can be found in 20% to 25% of patients with Brugada syndrome (BrS) and a pathogenic/likely pathogenic variant in SCN5A is associated with a worse prognosis. The aim of this study is to define the diagnostic yield of a large gene panel with American College of Medical Genetics and Genomics variant classification and to assess prognosis of SCN5A and non-SCN5A variants. METHODS: All patients with BrS, were prospectively enrolled in the Universitair Ziekenhuis Brussel registry between 1992 and 2022. Inclusion criteria for the study were (1) BrS diagnosis; (2) genetic analysis performed with a large gene panel; (3) classification of variants following American College of Medical Genetics and Genomics guidelines. Patients with a pathogenic/likely pathogenic variant in SCN5A were defined as SCN5A+. Patients with a reported variant in a non-SCN5A gene or with no reported variants were defined as patients with SCN5A-. All variants were classified as missense or predicted loss of function. RESULTS: A total of 500 BrS patients were analyzed. A total of 104 patients (20.8%) were SCN5A+ and 396 patients (79.2%) were SCN5A-. A non-SCN5A gene variant was found in 75 patients (15.0%), of whom, 58 patients (77.3%) had a missense variant and 17 patients (22.7%) had a predicted loss of function variant. At a follow-up of 84.0 months, 48 patients (9.6%) experienced a ventricular arrhythmia (VA). Patients without any variant had higher VA-free survival, compared with carriers of a predicted loss of function variant in SCN5A+ or non-SCN5A genes. There was no difference in VA-free survival between patients without any variant and missense variant carriers in SCN5A+ or non-SCN5A genes. At Cox analysis, SCN5A+ or non-SCN5A predicted loss of function variant was an independent predictor of VA. CONCLUSIONS: In a large BrS cohort, the yield for SCN5A+ is 20.8%. A predicted loss of function variant carrier is an independent predictor of VA.

Genetics in Probands With Idiopathic Ventricular Fibrillation: A Multicenter Study.

BACKGROUND: Different genes have been associated with idiopathic ventricular fibrillation (IVF); however, there are no studies correlating genotype with phenotype. OBJECTIVES: The aim of this study was to define the genetic background of probands with IVF using large gene panel analysis and to correlate genetics with long-term clinical outcomes. METHODS: All consecutive probands with a diagnosis of IVF were included in a multicenter retrospective study. All patients had: 1) IVF diagnosis throughout the follow-up; and 2) genetic analysis with a broad gene panel. All genetic variants were classified as pathogenic/likely pathogenic (P+), variants of unknown significance (VUS) or no variants (NO-V), following current guidelines of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology. The primary endpoint was occurrence of ventricular arrhythmias (VA). RESULTS: Forty-five consecutive patients were included. A variant was found in 12 patients, 3 P+ and 9 VUS carriers. After a mean follow-up time of 105.0 months, there were no deaths and 16 patients (35.6%) experienced a VA. NO-V patients had higher VA free survival during the follow-up, compared with both VUS (72.7% vs 55.6%, log-rank P < 0.001) and P+ (72.7% vs 0%, log-rank P = 0.013). At Cox analysis, P+ or VUS carrier status was a predictor of VA occurrence. CONCLUSIONS: In probands with IVF, undergoing genetic analysis with a broad panel, the diagnostic yield for P+ is 6.7%. P+ or VUS carrier status is a predictor of VA occurrence.

Hybrid atrial fibrillation ablation: long-term outcomes from a single-centre 10-year experience.

AIMS: Hybrid atrial fibrillation (AF) ablation is a promising approach in non-paroxysmal AF. The aim of this study is to assess the long-term outcomes of hybrid ablation in a large cohort of patients after both an initial and as a redo procedure. METHODS AND RESULTS: All consecutive patients undergoing hybrid AF ablation at UZ Brussel from 2010 to 2020 were retrospectively evaluated. Hybrid AF ablation was performed in a one-step procedure: (i) thoracoscopic ablation followed by (ii) endocardial mapping and eventual ablation. All patients received PVI and posterior wall isolation. Additional lesions were performed based on clinical indication and physician judgement. Primary endpoint was freedom from atrial tachyarrhythmias (ATas). A total of 120 consecutive patients were included, 85 patients (70.8%) underwent hybrid AF ablation as first procedure (non-paroxysmal AF 100%), 20 patients (16.7%) as second procedure (non-paroxysmal AF 30%), and 15 patients (12.5%) as third procedure (non-paroxysmal AF 33.3%). After a mean follow-up of 62.3 months ± 20.3, a total of 63 patients (52.5%) experienced ATas recurrence. Complications occurred in 12.5% of patients. There was no difference in ATas between patients undergoing hybrid as first vs. redo procedure (P = 0.53). Left atrial volume index and recurrence during blanking period were independent predictors of ATas recurrence. CONCLUSION: In a large cohort of patients undergoing hybrid AF ablation, the survival from ATas recurrence was 47.5% at ≈5 years follow-up. There was no difference in clinical outcomes between patients undergoing hybrid AF ablation as first procedure or as a redo.

Genetic testing in children with Brugada syndrome: results from a large prospective registry.

AIMS: A pathogenic/likely pathogenic (P/LP) variant in SCN5A is found in 20-25% of patients with Brugada syndrome (BrS). However, the diagnostic yield and prognosis of gene panel testing in paediatric BrS is unclear. The aim of this study is to define the diagnostic yield and outcomes of SCN5A gene testing with ACMG variant classification in paediatric BrS patients compared with adults. METHODS AND RESULTS: All consecutive patients diagnosed with BrS, between 1992 and 2022, were prospectively enrolled in the UZ Brussel BrS registry. Inclusion criteria were: (i) BrS diagnosis; (ii) genetic analysis performed with a large gene panel; and (iii) classification of gene variants following ACMG guidelines. Paediatric patients were defined as ≤16 years of age. The primary endpoint was ventricular arrhythmias (VAs). A total of 500 BrS patients were included, with 63 paediatric patients and 437 adult patients. Among children with BrS, 29 patients (46%) had a P/LP variant (P+) in SCN5A and no variants were found in 34 (54%) patients (P-). After a mean follow-up of 125.9 months, 8 children (12.7%) experienced a VA, treated with implanted cardioverter defibrillator shock. At survival analysis, P- paediatric patients had higher VA-free survival during the follow-up, compared with P+ paediatric patients. P+ status was an independent predictor of VA. There was no difference in VA-free survival between paediatric and adult BrS patients for both P- and P+. CONCLUSION: In a large BrS cohort, the diagnostic yield for P/LP variants in the paediatric population is 46%. P+ children with BrS have a worse arrhythmic prognosis.

Pulmonary vein size is associated with reconnection following cryoballoon ablation of atrial fibrillation.

BACKGROUND: The second-generation cryoballoon (CB) has proven to be a highly effective ablative strategy in patients with symptomatic atrial fibrillation (AF). This study sought to investigate the anatomical characteristics of pulmonary veins (PVs) and the relationship between their size, ovality, and late reconnections in a large cohort of patients undergoing repeat ablation for recurrence of atrial arrhythmias. METHODS AND RESULTS: A total of 152 consecutive patients (98 males, 64.5%; mean age 64.9 ± 9.6 years) underwent a repeat ablation for recurrent atrial tachyarrhythmias after a median time of 6.5 months [IQR 11] from the index CB ablation. All repeat ablations were performed using a 3-dimensional electro-anatomical mapping system. Among all 593 PVs, 134 (22.6%) showed a late PV reconnection in 95 patients (0.88 per patient), at the time of repeat ablation procedure. There was a significant difference in ovality between left- and right-sided PVs (p < 0.001). Greater diameters of left superior PV, left inferior PV, and right inferior PV ostia (both maximum and minimum) and higher index ovality were significantly associated with late PV reconnection. CONCLUSIONS: The rate of late PV reconnection after CB ablation was low (0.88 PVs/patient). Left-sided PVs were more oval than septal PVs. Larger PV dimensions and higher ovality index were significantly associated with reconnections in all PVs except for RSPV.

Incidence and Predictors of Cardiac Arrhythmias in Patients With COVID-19.

Background: Coronavirus disease 2019 (COVID-19) is a systemic disease caused by severe acute respiratory syndrome coronavirus 2. Arrhythmias are frequently associated with COVID-19 and could be the result of inflammation or hypoxia. This study aimed to define the incidence of arrhythmias in patients with COVID-19 and to correlate arrhythmias with pulmonary damage assessed by computed tomography (CT). Methods: All consecutive patients with a COVID-19 diagnosis hospitalized at Universitair Ziekenhuis Brussel, Belgium, between March 2020 and May 2020, were screened. All included patients underwent a thorax CT scan and a CT severity score, a semiquantitative scoring system of pulmonary damage, was calculated. The primary endpoint was the arrhythmia occurrence during follow-up. Results: In this study, 100 patients were prospectively included. At a mean follow-up of 19.6 months, 25 patients with COVID-19 (25%) experienced 26 arrhythmic episodes, including atrial fibrillation in 17 patients, inappropriate sinus tachycardia in 7 patients, atrial flutter in 1 patient, and third-degree atrioventricular block in 1 patient. No ventricular arrhythmias were documented. Patients with COVID-19 with arrhythmias showed more often need for oxygen, higher oxygen maximum flow, longer QTc at admission, and worse damage at CT severity score. In univariate logistic regression analysis, significant predictors of the primary endpoint were: the need for oxygen therapy (odds ratio [OR] 4.59, 95% CI 1.44-14.67, p = 0.01) and CT severity score of pulmonary damage (OR per 1 point increase 1.25, 95% CI 1.11-1.4, p < 0.001). Conclusions: In a consecutive cohort of patients with COVID-19 the incidence of cardiac arrhythmias was 25%. The need for oxygen therapy and CT severity score were predictors of arrhythmia occurrence during follow-up.

Atrial Fibrillation Global Changes after Pulmonary Vein and Posterior Wall Isolation: A Charge Density Mapping Study.

BACKGROUND: Non-contact charge density (CD) mapping allows a global visualization of left atrium (LA) activation and of activation patterns during atrial fibrillation (AF). The aim of this study was to analyze, with CD mapping, the changes in persistent AF induced by pulmonary vein isolation (PVI) and LA posterior wall isolation (LAPWI). METHODS: Patients undergoing PVI + LAPWI using the Arctic Front Advance PROTM cryoballoon system were included in the study. CD maps were created during AF at baseline, after PVI and after LAPWI. Three distinct activation patterns were identified in the CD maps: localized irregular activation (LIA), localized rotational activation (LRA) and focal centrifugal activation (FCA). LA maps were divided into the following regions: anterior, septal, lateral, roof, posterior, inferior. RESULTS: Eleven patients were included, with a total of 33 maps and 198 AF regions analyzed. Global and regional AF cycle lengths significantly increased after PVI and LAPWI. Baseline analysis demonstrated higher LIA, LRA and FCA numbers in the posterior and anterior regions. After PVI, there was no change in LIA, LRA and FCA occurrence. After PVI + LAPWI, a significant decrease in LRA was observed with no difference in LIA and FCA occurrence. In the regional analysis, there was a significant reduction in the LIA number in the inferior region, in the LRA number in the roof and posterior regions and in the FCA number in the lateral region. CONCLUSIONS: A global reduction in the LRA number was observed only after PVI + LAPWI; it was driven by a reduction in rotational activity in the roof and posterior regions.

Durability of pulmonary vein isolation following cryoballoon ablation: Lessons from a large series of repeat ablation procedures.

Introduction: The second-generation cryoballoon (CB) has emerged in the last decade as an effective treatment for atrial fibrillation (AF). This study sought to analyze the rate of PV reconnection following CB ablation, evaluate the most frequent PV sites of conduction recovery and finally to assess procedural and biophysical indicators of reconnection in a large cohort of patients undergoing repeat ablation for recurrence of atrial arrhythmias. Methods and Results: A total of 300 consecutive patients (189 males, 63%; mean age 63.0 ± 11.1 years) underwent a repeat ablation after 18.2 ± 10.8 months from the index CB ablation. All repeat ablations were performed using a 3-dimensional electro-anatomical mapping system. Among all 1178 PVs, 209 (17.7%) showed a late PV reconnection in 177 patients (1.18 per patient), at the time of repeat ablation procedure. Overall, persistent PV isolation could be documented in 969 of 1178 PVs (82.3%). In 123 of 300 patients (41%), persistent isolation could be demonstrated in all PVs, whereas PV reconnection could be documented in 177 patients (59%). In the multivariable analysis, nadir temperature (p = 0.03), time to PV isolation (p = 0.01) and failure to achieve - 40 °C within 60 s (p = 0.05) were independently associated with late PV reconnection. Conclusions: The rate of late PV reconnection after CB ablation was low (1.18 PVs/patient). The most frequent sites of reconnections were the superior-anterior portions for the upper PVs and the inferior-posterior portions for the lower PVs. Faster time to isolation, colder nadir temperatures and achievement of - 40 °C within 60 s were associated with durable PV isolation.

Comparison between the novel diamond temp and the classical 8-mm tip ablation catheters in the setting of typical atrial flutter.

PURPOSE: Radiofrequency (RF) catheter ablation is widely accepted as a first-line therapy for cavotricuspid isthmus (CTI)-dependent atrial flutter (AFL). The novel DiamondTemp (DT) catheter with temperature feedback during RF ablation has been released recently on the market. The purpose of this study was to evaluate the impact of DiamondTemp (DT) technology on ablation efficiency during AFL. METHODS: In this single-center study, 30 consecutive patients with typical AFL indicated to ablation of CTI were included. The first 15 patients underwent CTI ablation using 8-mm tip catheter, and the following 15 patients underwent temperature-controlled RF ablation using DT catheter. The endpoints were number and mean total duration of RF applications, mean temperature reached in the setting of CTI, procedural times, and fluoroscopy times. RESULTS: There were no significant differences between the two groups concerning baseline characteristics. Mean duration of the each application (71.5 s ± 30.6 vs 12.4 s ± 13.2, p value < 0.001), mean total duration of RF applications (517,73 s ± 377,96 vs 112,8 s ± 43,58; p value < 0.001), procedural times (51.6 min ± 24.2 vs 38.6 ± 8.2; p = 0.03), and fluoroscopy times (16.2 min ± 10.2 vs 8 min ± 4.24; p = 0.005) were longer in the 8-mm ablation catheter group. Mean temperature measurements (51.9 °C ± 3.59 vs 56.7 °C ± 3.34, p value < 0.003) were as well lower in the 8-mm ablation catheter group. CONCLUSIONS: Catheter ablation of CTI-dependent AFL by means of DT resulted in a significant reduction of total and single application RF delivery time, procedure, and fluoroscopy times.

Feasibility and safety of left atrial posterior wall isolation with a new Cryoballoon technology in patients with persistent atrial fibrillation.

BACKGROUND: Left atrial posterior wall isolation (LAPWI) is often performed in addition to pulmonary vein isolation (PVI) in the setting of persistent atrial fibrillation (AF) ablation. The aim of this study was to evaluate the feasibility and safety of a new cryoballoon ablation system in achieving PVI + LAPWI isolation. METHODS: The study was a prospective, non-randomized, single center study. Forty consecutive patients, undergoing PVI + LAPWI with the novel POLARx™, were compared to 40 consecutive patients who underwent the same procedure with the established Arctic Front Advance PRO™. RESULTS: Acute isolation was achieved in all PVs in both groups and left posterior wall isolation (LAPWI) was achieved in 38 patients (95%) in the POLARx group and in 36 patients (90%) in Arctic Front group. Procedural outcomes were similar between both groups, except for lower temperatures during cryoenergy in the POLARx group, for both pulmonary vein isolation (PVI) and LAPWI. CONCLUSION: LAPWI + PVI with the novel POLARx™ Cryoballoon is feasible and safe; the results are comparable with the Arctic Front Advance PRO™ system.

SCN5A mutation in Brugada syndrome is associated with substrate severity detected by electrocardiographic imaging and high-density electroanatomic mapping.

BACKGROUND: Brugada syndrome (BrS) is caused by mutations in SCN5A gene in 15%-20% of cases. Previous studies showed worse prognosis in SCN5A mutation carriers (SCN5A+). To date, there are no data on genotype-phenotype correlation with electrocardiographic (ECG) imaging (ECGI) and high-density epicardial electroanatomic map. OBJECTIVE: This study aimed to correlate SCN5A mutation with substrate severity in BrS assessed by ECGI and high-density electroanatomic map. METHODS: All consecutive BrS patients undergoing ECGI and high-density epicardial electroanatomic map with HD Grid Mapping Catheter were retrospectively analyzed. On ECGI, the following parameters were analyzed before and after ajmaline administration: right ventricular outflow tract (RVOT) activation time (RVOT-AT) and RVOT recovery time (RVOT-RT). On electroanatomic map, the parameters analyzed before and after ajmaline were high-frequency potential activation time (HFPat), high-frequency potential duration (HFPd), high-frequency potential amplitude (HFPa), low-frequency potential activation time (LFPat), low-frequency potential duration (LFPd), and low-frequency potential amplitude (LFPa). RESULTS: Thirty-nine BrS patients with ECGI were included. Eight patients (20.5%) were SCN5A+. At baseline ECGI map, mean RVOT-RT was longer in SCN5A+ (P = .024). After ajmaline administration, SCN5A+ patients showed longer RVOT-AT (125.6 vs 100.8 ms; P = .045) and longer RVOT-RT (426.4 vs 397 ms; P = .033). After ajmaline administration, SCN5A+ showed longer HFPat (164.1 vs 119.5 ms; P = .041); longer LFPat (272.7 vs 200.5 ms; P = .018); and longer LFPd (211.9 vs 151.2 ms; P = .033). CONCLUSION: In BrS, SCN5A+ patients compared with SCN5A- patients exhibit marked depolarization and repolarization abnormalities as assessed by ECGI and epicardial high-density electroanatomic map.

Ajmaline-Induced Abnormalities in Brugada Syndrome: Evaluation With ECG Imaging.

Background The rate of sudden cardiac death (SCD) in Brugada syndrome (BrS) is ≈1%/y. Noninvasive electrocardiographic imaging is a noninvasive mapping system that has a role in assessing BrS depolarization and repolarization abnormalities. This study aimed to analyze electrocardiographic imaging parameters during ajmaline test (AJT). Methods and Results All consecutive epicardial maps of the right ventricle outflow tract (RVOT-EPI) in BrS with CardioInsight were retrospectively analyzed. (1) RVOT-EPI activation time (RVOT-AT); (2) RVOT-EPI recovery time, and (3) RVOT-EPI activation-recovery interval (RVOT-ARI) were calculated. ∆RVOT-AT, ∆RVOT-EPI recovery time, and ∆RVOT-ARI were defined as the difference in parameters before and after AJT. SCD-BrS patients were defined as individuals presenting a history of aborted SCD. Thirty-nine patients with BrS were retrospectively analyzed and 12 patients (30.8%) were SCD-BrS. After AJT, an increase in both RVOT-AT [105.9 milliseconds versus 65.8 milliseconds, P<0.001] and RVOT-EPI recovery time [403.4 milliseconds versus 365.7 milliseconds, P<0.001] was observed. No changes occurred in RVOT-ARI [297.5 milliseconds versus 299.9 milliseconds, P=0.7]. Before AJT no differences were observed between SCD-BrS and non SCD-BrS in RVOT-AT, RVOT-EPI recovery time, and RVOT-ARI (P=0.9, P=0.91, P=0.86, respectively). Following AJT, SCD-BrS patients showed higher RVOT-AT, higher ∆RVOT-AT, lower RVOT-ARI, and lower ∆RVOT-ARI (P<0.001, P<0.001, P=0.007, P=0.002, respectively). At the univariate logistic regression, predictors of SCD-BrS were the following: RVOT-AT after AJT (specificity: 0.74, sensitivity 1.00, area under the curve 0.92); ∆RVOT-AT (specificity: 0.74, sensitivity 0.92, area under the curve 0.86); RVOT-ARI after AJT (specificity 0.96, sensitivity 0.58, area under the curve 0.79), and ∆RVOT-ARI (specificity 0.85, sensitivity 0.67, area under the curve 0.76). Conclusions Noninvasive electrocardiographic imaging can be useful in evaluating the results of AJT in BrS.

Single procedural outcomes in the setting of percutaneous ablation for persistent atrial fibrillation: a propensity-matched score comparison between different strategies.

BACKGROUND: Catheter ablation for persistent atrial fibrillation (persAF) is associated with less favorable outcomes than for paroxysmal AF. To improve success rates, left atrial (LA) substrate modification is frequently performed in addition to pulmonary vein isolation (PVI). The purpose of the study was to compare 4 different ablation approaches using radiofrequency catheter ablation (RFCA) or cryoballoon ablation (CB-A) for persAF and to evaluate the respective outcomes on a midterm follow-up of 12 months. METHODS: We did a propensity score-matched comparison of 30 patients undergoing PVI + LA posterior wall isolation (LAPWI) with CB-A, 30 patients who underwent PVI + linear ablation (roof and mitral lines) using RFCA, 60 patients with PVI alone using CB-A, and 60 patients who had PVI alone using RFCA. The endpoint was recurrence of documented atrial tachyarrhythmias (ATas) > 30 s at 1-year follow-up. RESULTS: After 12 months, freedom from ATas after a single procedure was 83.3% in the PVI + LAPWI group, 46.7% in the PVI + linear ablation group, 58.3% in the PVI-alone CB-A group, and 61.6% PVI-alone RFCA (p = 0.03). Moreover, freedom from ATas was significantly higher comparing the PVI + LAPWI group with each of the other groups. CONCLUSIONS: In this propensity-matched comparison of strategies for persAF, LAPW ablation in addition to PVI with CB-A seems to improve 1-year outcome in comparison to PVI + linear ablation using RFCA and to PVI alone using RFCA or CB-A. Randomized comparisons are eagerly awaited.

High-density epicardial mapping in Brugada syndrome: Depolarization and repolarization abnormalities.

BACKGROUND: The pathogenesis of Brugada syndrome (BrS) and consequently of abnormal electrograms (aEGMs) found in the epicardium of the right ventricular outflow tract (RVOT-EPI) is controversial. OBJECTIVE: The purpose of this study was to analyze aEGM from high-density RVOT-EPI electroanatomic mapping (EAM). METHODS: All patients undergoing RVOT-EPI EAM with the HD-Grid catheter for BrS were retrospectively included. Maps were acquired before and after ajmaline, and all patients had concomitant noninvasive electrocardiographic imaging with annotation of RVOT-EPI latest activation time (RVOTat). High-frequency potentials (HFPs) were defined as ventricular potentials occurring during or after the far-field ventricular EGM showing a local activation time (HFPat). Low-frequency potentials (LFPs) were defined as aEGMs occurring after near-field ventricular activation showing fractionation or delayed components. Their activation time from surface ECG was defined as LFPat. RESULTS: Fifteen consecutive patients were included in the study. At EAM before ajmaline, 7 patients (46.7%) showed LFPs. All patients showed HFPs before and after ajmaline and LFPs after ajmaline. Mean HFPat (134.4 vs 65.3 ms, P <.001), mean LFPat (224.6 vs 113.6 ms, P <.001), and mean RVOTat (124.8 vs 55.9 ms, P <.001) increased after ajmaline. RVOTat correlated with HFPat before (ρ = 0.76) and after ajmaline (ρ = 0.82), while RVOTat was shorter than LFPat before (P <.001) and after ajmaline (P <.001). BrS patients with history of aborted sudden cardiac death had longer aEGMs after ajmaline. CONCLUSION: Two different types of aEGMs are described from BrS high-density epicardial mapping. This might correlate with depolarization and repolarization abnormalities.

Lean Perspectives in an Organizational Change in a Scientific Direction of an Italian Research Institute: Experience of the Cancer Institute of Bari.

Lean management is a relatively new organizational vision transferred from the automotive industry to the healthcare and administrative sector based on analyzing a production process to emphasize value and reduce waste. This approach is particularly interesting in a historical moment of cuts and scarcity of economic resources and could represent a low-cost organizational solution in many production companies. In this work, we analyzed the presentation and the initial management of current ministerial research projects up to the approval by the Scientific Directorate of an Italian research institute. Furthermore, the initial mode in 2021 ("as is") and the potential mode ("to be") according to a Lean model are studied, according to the current barriers highlighted by the final users of the process and carrying out some perspective analyses with some reference indicators.

Procedural Safety and Efficacy for Pulmonary Vein Isolation with the Novel Polarx™ Cryoablation System: A Propensity Score Matched Comparison with the Arctic Front™ Cryoballoon in the Setting of Paroxysmal Atrial Fibrillation.

BACKGROUND: The novel Polarx™ cryoablation system is currently being studied for atrial fibrillation (AF) ablation. To the best of our knowledge, no study comparing the novel cryoablation system with the standard Arctic Front™ cryoballoon is available in today's literature. This study aims to compare Polarx™ and Arctic Front™ cryoballoon in terms of safety and efficacy. METHODS: From a total cohort of 202 patients who underwent pulmonary vein (PV) isolation for paroxysmal AF through cryoablation, a population of 30 patients who used Polarx™ were compared with 30 propensity-score matched patients who used Arctic Front™. RESULTS: Pulmonary vein occlusion and electrical isolation were achieved in all (100%) veins with a mean number of 1.09 ± 0.3 occlusion per vein using Polarx™ and 1.19 ± 0.5 occlusion per vein using Arctic Front™ (p = 0.6). Shorter procedure and fluoroscopy time were observed with Polarx™ group (60.5 ± 14.23 vs 73.43 ± 13.26 mins, p = 0.001; 12.83 ± 6.03 vs 17.23 ± 7.17 mins, p = 0.01, respectively). Lower cumulative freeze duration per vein was also observed with Polarx™ (203.38 ± 72.03 vs 224.9 ± 79.35 mins, p = 0.02). There was no significant difference in isolation time between the two groups (34.47 ± 21.23 vs 34.18 ± 26.79 secs, p = 0.9). CONCLUSIONS: The novel Polarx™ cryoablation system showed similar efficacy in vein occlusion and isolation and safety profile when compared to Arctic Front™ cryoablation system. Procedure time, fluoroscopy time, and cumulative freeze duration were significantly lower with Polarx™ cryoablation system.

Cardiac parasympathetic modulation in the setting of radiofrequency ablation for atrial fibrillation.

The cardiac autonomic nervous system plays an important role in the genesis and maintenance of atrial fibrillation. Although, pulmonary vein isolation is the cornerstone in today's approach to atrial fibrillation ablation, a considerable proportion of patients will recur with atrial arrhythmias following this procedure, especially in the non-paroxysmal forms. The pulmonary vein isolation indirectly targets and ablate the ganglionated plexi. This might ultimately enhance the efficacy of the procedure, but an optimal ablation strategy and a reliable method to confirm and quantify the efficacy of vagal denervation following the procedure might be necessary, thus leading to significantly better results.

High vagal tone predicts pulmonary vein reconnection after cryoballoon ablation for paroxysmal atrial fibrillation.

BACKGROUND: Pulmonary vein (PV) isolation is an established treatment for paroxysmal drug-refractory atrial fibrillation (AF). High parasympathetic tone and reconnection of PVs have demonstrated to be possible culprits of AF recurrence after ablation. Our aim was to investigate the association between parasympathetic tone and reconnected PVs in patients with paroxysmal AF. METHODS: Consecutive patients who underwent a redo catheter ablation procedure for atrial tachyarrhythmia recurrence by means of 3D electroanatomic mapping with documentation of presence or absence of PVs reconnection following an initial procedure of cryoballoon (CB) ablation for symptomatic drug-refractory paroxysmal AF were screened for the study. RESULTS: A total of 92 patients were included, of whom 50 (54.35%) were males. Reconnected PVs were found in 64 (69%) patients. PVs reconnection could be predicted by DC (C-statistic = .770), by SDNNI (C-statistic = .714) and by absolute VLF power (C-statistic = .722), while right-sided PVs reconnection could be better predicted by DC (C-statistic = .848) and by SDNNI (C-statistic = .761). In multivariate binary logistic regression analysis, a DC value ≥6.45 ms and an absolute VLF power value ≥160 ms2 were associated with three times and five times higher odds of PVs reconnection, respectively. On a vein-per-vein analysis, absolute VLF power ≥160 ms2 was associated with three times higher odds, while reaching of -40°C within 60 s was associated with three times lower odds of PVs reconnection. CONCLUSION: High parasympathetic tonus accurately predicts PVs reconnection. On a vein-per-vein analysis, parasympathetic markers along with biophysical parameters predicted PVs reconnection. On a case-by-case analysis, parasympathetic markers were the only predictors of PVs reconnection, thus being a robust PVs reconnection prediction tool.

Comparison between superior vena cava ablation in addition to pulmonary vein isolation and standard pulmonary vein isolation in patients with paroxysmal atrial fibrillation with the cryoballoon technique.

BACKGROUND: Paroxysmal atrial fibrillation (PAF) can be triggered by non-pulmonary vein foci, like the superior vena cava (SVC). The latter is correlated with improved result in terms of freedom from atrial tachycardias (ATs), when electrical isolation of this vessel utilizing radiofrequency energy (RF) is achieved. OBJECTIVES: Evaluate the clinical impact, in patients with PAF, of the SVC isolation (SVCi) in addition to ordinary pulmonary vein isolation (PVI) by means of the second-generation cryoballoon (CB) METHODS: A total of 100 consecutive patients that underwent CB ablation for PAF were retrospectively selected. Fifty consecutive patients received PVI followed by SVCi by CB application, and the following 50 consecutive patients received standard PVI. All patients were followed 12 months. RESULTS: The mean time to SVCi was 36.7 ± 29.0 s and temperature at SVC isolation was - 35 (- 18 to - 40) °C. Real-time recording (RTR) during SVCi was observed in 42 (84.0%) patients. At the end of 12 months of follow-up, freedom from ATs was achieved in 36 (72%) patients in the PVI only group and in 45 (90%) patients of the SVC and PV isolation group (Fisher's exact test p = 0.039, binary logistic regression: p = 0.027, OR = 0.28, 95%CI = 0.09-0.86). In survival analysis, SVC and PV isolation group was also associated with improved freedom from ATs (log-rank test: p = 0.017, Cox regression: p = 0.026, HR = 0.31, 95%CI = 0.11-0.87). CONCLUSION: Superior vena cava isolation with the CB in addition to PVI might improve freedom from ATs if compared to PVI alone at 1-year follow-up.

Substrate mapping of the left atrium in persistent atrial fibrillation: spatial correlation of localized complex conduction patterns in global charge-density maps to low-voltage areas in 3D contact bipolar voltage maps.

PURPOSE: This study aimed to investigate the spatial relationship between low-voltage areas (LVAs) in bipolar voltage mapping (BVM) and localized complex conduction (LCC)-cores in a global, non-contact, charge-density-based imaging, and mapping system (AcM). METHODS: Patients with history of index PVI for PsAF and scheduled for a repeat ablation procedure for recurrence of the same arrhythmia were enrolled between August 2018 and February 2020. All patients underwent both substrate mappings of the left atrium (LA) with the CARTO 3D map-ping system and with AcM. RESULTS: Ten patients where included in our analysis. All presented with persistency of PVI in all veins at the moment of repeat procedure. There was no linear relationship in BVM maps between SR and CSd (correlation coefficient 0.31 ± 0.15), SR and CSp (0.36 ± 0.12) and CSd and CSp (0.43 ± 0.10). The % overlap of localized irregular activation (LIA), localized rotational activation (LRA) and Focal (F) regions with LVA was lower at 0.2 mV compared to 0.5 mV (4.97 ± 7.39%, 3.27 ± 5.25%, 1.09 ± 1.92% and 12.59 ± 11.81%, 7.8 ± 9.20%, 4.62 ± 5.27%). Sensitivity and specificity are not significantly different when comparing composite maps with different LVA cut-offs. AURC was 0.46, 0.48, and 0.39 for LIA, LRA, and Focal, respectively. CONCLUSION: Due to wave front direction dependency, LVAs mapped with BVM in sinus rhythm and during coronary sinus pacing only partially overlap in patients with PsAF. LCC-cores mapped during PsAF partially co-localize with LVAs.