The Arrhythmia Institute

For patients with atrial fibrillation, the use of oral anticoagulant therapy to prevent stroke is limited by the risk of bleeding. Left atrial appendage closure is considered for patients who are unsuitable candidates for long-term anticoagulation, but its role in patients who are eligible for anticoagulants has not been established. In this ongoing, prospective, international, randomized trial involving patients with atrial fibrillation who were suitable candidates for anticoagulation, we randomly assigned patients in a 1:1 ratio to receive either device-based left atrial appendage closure (device group) or non-vitamin K antagonist oral anticoagulant (NOAC) therapy (anticoagulation group). The primary efficacy end point - a composite of death from cardiovascular causes, stroke, or systemic embolism - was tested for noninferiority (noninferiority margin, 4.8 percentage points) after 3 years of follow-up. The primary safety end point, non-procedure-relatedbleeding, was tested for superiority. Of the 3000 patients who underwent randomization, 1499 were assigned to the device group and 1501 to the anticoagulation group. The mean (±SD) age of the patients was 71.7±7.5 years, 31.9% of the patients were women, and the mean CHA2DS2-VASc score was 3.5±1.3. At 3 years, a primary efficacy end-point event had occurred in 81 patients (Kaplan-Meier estimate, 5.7%) in the device group and in 65 patients (Kaplan-Meier estimate, 4.8%) in the anticoagulation group (difference, 0.9 percentage points; 95% confidence interval [CI], -0.8 to 2.6; P<0.001 for noninferiority). Non-procedure-related bleeding occurred in 154 patients (Kaplan-Meier estimate, 10.9%) in the device group and in 260 patients (Kaplan-Meier estimate, 19.0%) in the anticoagulation group (hazard ratio, 0.55; 95% CI, 0.45 to 0.67; P<0.001 for superiority). Among patients with atrial fibrillation who were candidates for anticoagulation, device-based left atrial appendage closure was noninferior to NOAC therapy with respect to a composite of death from cardiovascular causes, stroke, or systemic embolism and was superior to NOAC therapy for non-procedure-related bleeding at 3 years. (Funded by Boston Scientific; CHAMPION-AF ClinicalTrials.gov number, NCT04394546.).

ABSTRACTBackgroundWomen with congenital and acquired long QT syndrome (LQTS) have increased risk of adverse cardiac events after adolescence, mainly due to sex hormones modulating the KCNH2 cardiac potassium channel. We hypothesized that sex hormones may influence ventricular tachyarrhythmia risk during the menstrual cycle in women treated with QT‐prolonging drugs.ObjectiveTo evaluate the association between repolarization dynamics and sex hormone levels during the menstrual cycle in women treated with QT‐prolonging drugs.MethodsWe prospectively enrolled 41 women treated with dofetilide or sotalol (N = 20) and healthy controls (N = 21). Participants underwent three 7‐day ECG recordings during their menstrual cycles, with concurrent saliva hormone measurements. Primary ECG outcomes were QT‐Apex (early repolarization) and QT interval (total repolarization time), adjusted for heart rate.ResultsThe mean age was 51 ± 11 years in the treatment group and 42 ± 12 years in controls. In women treated with QT‐prolonging drugs, linear mixed‐effects models (adjusted for RR interval) showed inverse correlations of QT‐Apex with progesterone‐to‐estradiol ratio (p = 0.018) and testosterone (p = 0.026), and a direct correlation with estradiol (p = 0.004). QT interval inversely correlated with progesterone‐to‐estradiol ratio (p = 0.012). No significant correlations were observed in controls.ConclusionsSex hormones are significantly associated with ventricular repolarization dynamics during the menstrual cycle in women treated with QT‐prolonging drugs, suggesting a mechanism for sex‐specific arrhythmia susceptibility.

Abstract Background Atrial fibrillation (AF) is the most prevalent arrhythmia, often leading to significant morbidity and mortality. Pulmonary vein isolation (PVI) is the cornerstone of catheter ablation for AF; however, the efficacy of adding superior vena cava isolation (SVCI) as an adjunct remains uncertain. Purpose This systematic review and meta-analysis aim to evaluate the impact of SVCI on atrial tachyarrhythmias (AT) recurrence, procedural complications, and overall procedural efficacy when combined with PVI. Methods A comprehensive literature search was conducted across PubMed, Embase, and Cochrane Library, to identify randomised controlled trials (RCTs) that assessed the effects of SVCI in addition to PVI. Data were analysed using random-effects models to pool risk ratios (RRs) and mean differences (MDs) with their 95% confidence intervals (CIs). All statistical analyses were performed using R verson 4.4.2. Heterogeneity was assessed using the I² statistics. Results A total of 5 RCTs comprising 698 patients were included in the analysis. Mean age ranged from 56 to 66 years, and 335 (47.9%) patients were randomised to PVI + SVCI. The addition of SVCI did not significantly reduce AT recurrence (RR 0.77; 95% CI: 0.51–1.17; P=0.22). Moreover, there were also no significant differences in the risk of clinical complications (RR 1.94; 95% CI 0.83–4.51; P=0.12) and in total procedure time (MD 2.83 min; 95% CI: -8.94 min to 14.59 min; P=0.64). However, performing SVCI in addition to PVI significantly increased fluorosocopy time (MD 3.89 min; 95% CI: 0.20 min to 7.58 min; P=0.04). Conclusions This meta-analysis indicates that adding SVCI to PVI does not lead to a significant reduction in AT recurrence, nor does it increase the risk of complications or total procedure time. However, fluoroscopy procedure time was significantly increased in the SVCI + PVI group when compared to PVI alone. These findings suggest that routine SVCI may not be warranted in standard AF ablation procedures. Further research is needed to explore the long-term implications of SVCI and to identify specific patient populations that may benefit from this approachFigure 1

IntroductionThe utilization of zero-fluoroscopy and reduced fluoroscopy strategies in catheter ablation (CA) for atrial fibrillation (AF) is increasing. This aims to minimize radiation exposure and associated adverse effects for operators, patients, and laboratory staff.ObjectiveWe aimed to define the freedom from atrial arrhythmias in patients undergoing CA employing a zero-fluoroscopy approach compared to the conventional fluoroscopic approach.MethodsProspective, observational, multicenter registry. We enrolled patients with paroxysmal (PAF) and persistent (PsAF) and a minimum 12-month follow-up. Additional analysis classifying groups in conventional fluoroscopy (>1 minute), zero-fluoroscopy, or very low fluoroscopy (<1 minute) were performed. The primary efficacy outcome was freedom from atrial arrhythmias.ResultsWe included 7,196 patients. The mean age was 66.7 years, females represented 39.8% of the cohort. Ablation was performed to treat PAF in 61.9% and psAF in 38.1%. A zero-fluoroscopy approach was chosen in 4,874 patients (67.7%), 2,322 (32.3%) used fluoroscopy, and 922 (12.8%) patients were utilized with very low fluoroscopy. Freedom from atrial arrhythmias after one year of follow-up was 81%. Notably, zero-fluoroscopy and fluoroscopy-based ablation strategies exhibited comparable freedom from atrial arrhythmias (HR=1.15, 95% CI 0.92-1.43, p=0.2). Similarly, there was no significant difference in the primary outcome when comparing zero-fluoroscopy versus very low fluoroscopy. The complication rate was 1.6% without significant differences between groups (p>0.05).ConclusionReduced fluoroscopy techniques demonstrated a similar long-term success rate compared to conventional fluoroscopy approaches without increase un complications. These findings endorse recent regulatory agency approvals of tools for performing CA of AF using these strategies.Freedom from atrial arrhythmias Complications

Abstract BackgroundLeft atrial appendage occlusion (LAAO) is increasingly used as an alternative to oral anticoagulation for stroke prevention in select patients with atrial fibrillation. Data on outcomes in racial and ethnic minority individuals are limited. This analysis assessed differences in the utilization and outcomes of LAAO by race and ethnicity in a large national registry.MethodsThis analysis acquired data on WATCHMAN FLX patients from the National Cardiovascular Data Registry (NCDR) LAAO Registry through September 2022. All patients with an attempted WATCHMAN FLX implantation and known race and ethnicity were included. Baseline characteristics and 1 year event rates were compared.ResultsA total of 97,185 patients were analyzed; 87,339 were White (90%), 3,750 Black (Black/African American 3.9%), and 2,866 Hispanic ([Hispanic/Latinx] 2.9%). Black and Hispanic patients were younger with a higher incidence of prior stroke and significant bleeding compared to White patients. Black and Hispanic patients were treated with LAAO in smaller numbers relative to their proportion of the US population. Rates of procedural success were similar between groups. Though direct oral anticoagulants were prescribed in most patients across the groups, dual and single antiplatelet therapy were prescribed more often in Black patients. Black patients had significantly higher rates of 1-year death and bleeding compared to White and Hispanic patients.ConclusionsPatients from racial and ethnic minority groups comprise a disproportionately small fraction of all patients who undergo LAAO. Black and Hispanic patients were younger but had significantly higher comorbidities compared to White patients. Procedural success was similar amongst the groups but Black patients experienced higher rates of death and bleeding at 1 year.Graphic AbstractWhat is knownThere is underutilization of LAAO among racial and ethnic minority patients with AF and there are racial and ethnic differences in periprocedural outcomes.What this study addsIn this study from a large US national registry of patients undergoing LAAO, Black patients were younger but had higher baseline comorbidities and experienced higher rates of bleeding at 45 days and 1-year and higher 1-year mortality. Further work is needed to enroll diverse patients into research trials and to provide equitable AF-related access to advanced care and intra- procedural and post-procedural care in US real-world practice.

Teleological causes have been generally disfavored in biological explanations because they have been thought to lack rigor or act as stand-ins for non-teleological processes which are simply not yet understood sufficiently. Teleological explanations in biology have been limited to only teleonomic causes, which are teleological causes that are due to codes or similarly reified mechanisms. However, advances in the conceptualization of teleological and teleonomic causation have allowed for more quantitative analyses of both. Additionally, although teleonomy has been historically excluded from potential causes of evolution, new research has shown that teleonomy actually plays a significant role in evolution. Combining these advances with advances in computability theory and information theory have allowed for a more rigorous and quantitative analysis of the capabilities and limitations of teleonomy in evolution.

The Real-World Experience of Catheter Ablation for Treatment of Symptomatic Paroxysmal and Persistent Atrial Fibrillation (REAL-AF) is a multicenter prospective registry of atrial fibrillation (AF) ablation. We sought to describe the baseline workflows of REAL-AF operators. REAL-AF enrolls high volume minimum fluoroscopy radiofrequency ablators. A 150 item questionnaire was administered to participating operators. Responses were analyzed using standard methods. Forty-two respondents had a mean 178.2 ± 89.2 yearly AF ablations, with 42.4 ± 11.9% being paroxysmal (PAF). Most operators performed ablation with uninterrupted or minimally interrupted anticoagulation (66.7% and 28.6%). Left atrial appendage (LAA) thrombus was most commonly ruled out with transesophageal echocardiography (33.3% and 42.9% for PAF and persistent AF). Consistent with registry design, radiofrequency energy (92.1% ± 18.8% of cases) and zero fluoroscopy ablation (73.8% goal 0 fluoroscopy) were common. The majority of operators relied on index-guided ablation (90.5%); Mean Visitag surpoint targets were higher anteriorly vs posteriorly (508.3 ± 49.8 vs 392.3 ± 37.0, p < 0.01), but power was similar. There was considerable heterogeneity related to gaps in current knowledge, such as lesion delivery targets and sites of extra-pulmonary vein ablation (most common was the posterior wall followed by the roof). Peri-procedural risk factor management of obesity, hypertension, and sleep apnea was common. There was a mean of 3.0 ± 1.2 follow-up visits at 12months. REAL-AF operators were high volume low fluoroscopy "real world" operators with good follow-up and adherence to known best-practices. There was disagreement related to knowledge gaps in guidelines.