The impact of common and rare genetic variants on bradyarrhythmia development.

To broaden our understanding of bradyarrhythmias and conduction disease, we performed common variant genome-wide association analyses in up to 1.3 million individuals and rare variant burden testing in 460,000 individuals for sinus node dysfunction (SND), distal conduction disease (DCD) and pacemaker (PM) implantation. We identified 13, 31 and 21 common variant loci for SND, DCD and PM, respectively.

Implantable cardioverter defibrillator use in arrhythmogenic right ventricular cardiomyopathy in North America and Europe.

Background And Aims: Implantable cardioverter-defibrillators (ICDs) are critical for preventing sudden cardiac death (SCD) in arrhythmogenic right ventricular cardiomyopathy (ARVC). This study aims to identify cross-continental differences in utilization of primary prevention ICDs and survival free from sustained ventricular arrhythmia (VA) in ARVC.

Methods: This was a retrospective analysis of ARVC patients without prior VA enrolled in clinical registries from 11 countries throughout Europe and North America.

Clinical Management of Brugada Syndrome: Commentary From the Experts.

Although there is consensus on the management of patients with Brugada Syndrome with high risk for sudden cardiac arrest, asymptomatic or intermediate-risk patients present clinical management challenges. This document explores the management opinions of experts throughout the world for patients with Brugada Syndrome who do not fit guideline recommendations. Four real-world clinical scenarios were presented with commentary from small expert groups for each case.

Aberrant activation of TCL1A promotes stem cell expansion in clonal haematopoiesis.

Mutations in a diverse set of driver genes increase the fitness of haematopoietic stem cells (HSCs), leading to clonal haematopoiesis. These lesions are precursors for blood cancers, but the basis of their fitness advantage remains largely unknown, partly owing to a paucity of large cohorts in which the clonal expansion rate has been assessed by longitudinal sampling. Here, to circumvent this limitation, we developed a method to infer the expansion rate from data from a single time point.

Increasing time between first diagnosis of atrial fibrillation and catheter ablation adversely affects long-term outcomes in patients with and without structural heart disease.

Introduction: Atrial Fibrillation (AF) is a common arrhythmia often comorbid with systolic or diastolic heart failure (HF). Catheter ablation is a more effective treatment for AF with concurrent left ventricular dysfunction, however, the optimal timing of use in these patients is unknown.

Methods: All patients that received a catheter ablation for AF(n = 9979) with 1 year of follow-up within the Intermountain Healthcare system were included.

Atrial fibrillation is a risk factor for major adverse cardiovascular events in COVID-19.

Background: New-onset atrial fibrillation (AF) during COVID-19 infection is associated with worse cardiovascular outcomes and mortality, with new-onset AF being associated with worse clinical outcomes than recurrent AF. However, it is not known whether a prior history of AF is an independent cardiovascular risk factor predicting worse outcomes in COVID-19 patients. The present investigation sought to determine whether AF should be considered a risk factor for worse outcomes in COVID-19 illness.

Annotation of the Complete Genome Sequences of Bacteriophages Sara and Birdfeeder.

Sara is a siphovirus with a linear 17,362bp genome containing 25 genes. Birdfeeder is a podovirus with a circularly permuted 53,897bp genome containing 52 genes. Sara and Birdfeeder were isolated from environmental samples in Plattsburgh, NY, USA and Forest Hill, MD, USA, respectively, using Microbacterium foliorum NRRL B-24224.

Arrhythmic risk prediction in arrhythmogenic right ventricular cardiomyopathy: external validation of the arrhythmogenic right ventricular cardiomyopathy risk calculator.

Aims: Arrhythmogenic right ventricular cardiomyopathy (ARVC) causes ventricular arrhythmias (VAs) and sudden cardiac death (SCD). In 2019, a risk prediction model that estimates the 5-year risk of incident VAs in ARVC was developed (ARVCrisk.com).

Low voltage-guided ablation of posterior wall improves 5-year arrhythmia-free survival in persistent atrial fibrillation.

Introduction: The posterior wall (PW) has been proposed as a standard target for ablation beyond pulmonary vein antral isolation (PVI) in patients with persistent atrial fibrillation (AF). However, studies have shown inconsistent outcomes with the addition of PW ablation. The presence or absence of low voltage on the PW may explain these inconsistencies.

Absent or Mild Coronary Calcium Predicts Low-Risk Stress Test Results and Outcomes in Patients Considered for Flecainide Therapy.

Background: Flecainide is a useful antiarrhythmic for atrial fibrillation (AF). However, because of ventricular proarrhythmia risk, a history of myocardial infarction (MI) or coronary artery disease (CAD) is a flecainide exclusion, and stress testing is used to exclude ischemia. We assessed whether absent/mild coronary artery calcium (CAC) can supplement or avoid the need for stress testing.

Long-term outcomes in patients treated with flecainide for atrial fibrillation with stable coronary artery disease.

Background: Class 1C antiarrhythmic drugs (AAD) have been associated with harm in patients treated for ventricular arrhythmias with a prior myocardial infarction. Consensus guidelines have advocated that these drugs not be used in patients with stable coronary artery disease (CAD). However, long-term data are lacking to know if unique risks exist when these drugs are used for atrial fibrillation (AF) in patients with CAD without a prior myocardial infarction.

Management of Congenital Long-QT Syndrome: Commentary From the Experts.

While published guidelines are useful in the care of patients with long-QT syndrome, it can be difficult to decide how to apply the guidelines to individual patients, particularly those with intermediate risk. We explored the diversity of opinion among 24 clinicians with expertise in long-QT syndrome. Experts from various regions and institutions were presented with 4 challenging clinical scenarios and asked to provide commentary emphasizing why they would make their treatment recommendations.

High Power Ultra Short Duration Ablation with HD Grid Improves Freedom from Atrial Fibrillation and Redo Procedures Compared to Circular Mapping Catheter.

Background: High power ultra-short duration (HPUSD) ablation has been advocated to prevent esophageal injuries during atrial fibrillation (AF) ablation procedures. Prior research using the standard circular mapping catheter (CMC) has shown that ultra-short ablations may compromise lesion durability resulting in an increased need for redo procedures. The purpose of this study was to determine if HD mapping of concealed pulmonary vein (PV) connections could improve freedom from atrial fibrillation and redo procedures compared to CMC guided AF ablation.

Multi-ancestry GWAS of the electrocardiographic PR interval identifies 202 loci underlying cardiac conduction.

The electrocardiographic PR interval reflects atrioventricular conduction, and is associated with conduction abnormalities, pacemaker implantation, atrial fibrillation (AF), and cardiovascular mortality. Here we report a multi-ancestry (N = 293,051) genome-wide association meta-analysis for the PR interval, discovering 202 loci of which 141 have not previously been reported. Variants at identified loci increase the percentage of heritability explained, from 33.

Genetic Susceptibility for Atrial Fibrillation in Patients Undergoing Atrial Fibrillation Ablation.

Background: Ablation is a widely used therapy for atrial fibrillation (AF); however, arrhythmia recurrence and repeat procedures are common. Studies examining surrogate markers of genetic susceptibility to AF, such as family history and individual AF susceptibility alleles, suggest these may be associated with recurrence outcomes. Accordingly, the aim of this study was to test the association between AF genetic susceptibility and recurrence after ablation using a comprehensive polygenic risk score for AF.

Spontaneous Atrial Fibrillation in Transgenic Goats With TGF (Transforming Growth Factor)-β1 Induced Atrial Myopathy With Endurance Exercise.

Background: There is increasing evidence that endurance exercise is associated with increased risk of atrial fibrillation (AF). However, it is unknown if the relationship between endurance exercise and AF is dependent on an atrial myopathy.

Methods: Six cardiac-specific TGF (transforming growth factor)-β1 transgenic and 6 wild-type (WT) goats were utilized for these studies.

Long-term outcomes after low power, slower movement versus high power, faster movement irrigated-tip catheter ablation for atrial fibrillation.

Background: High power, shorter duration (HPSD) ablation strategies have been advocated to increase efficacy and minimize posterior wall deep tissue thermal injury during atrial fibrillation (AF) ablation.

Objective: The purpose of this study was to determine the long-term outcomes of arrhythmia-free survival from AF and atrial flutter (AFL) between HPSD and low power, longer duration (LPLD) ablation strategies.

Methods: Of a total of 1333 first time AF ablation procedures with 3 years of follow-up, propensity-matched populations for baseline risk factors were created, comprising 402 patients treated with LPLD ablation (30 W for 5 seconds: posterior wall; 30 W for 10-20 seconds: anterior wall) and 402 patients treated with HPSD ablation (50 W for 2-3 seconds: posterior wall; 50 W for 5-15 seconds: anterior wall).

Cardiac Implantable Electronic Device Therapy: Permanent Pacemakers, Implantable Cardioverter Defibrillators, and Cardiac Resynchronization Devices.

Cardiac implantable electronic devices (CIEDs) provide lifesaving therapy for the treatment of bradyarrhythmias, ventricular tachyarrhythmias, and advanced systolic heart failure. Advances in CIED therapy have expanded the number of patients receiving permanent pacemakers, implantable cardioverter defibrillators, and cardiac resynchronization therapy devices. These devices improve quality of life and, in many cases, reduce mortality.