High-Density and Resolution Epicardial Mapping of the Atria: Translational Research with Clinical Impact.

The electrical arrhythmogenic substrate underlying the most common cardiac arrhythmia atrial fibrillation (AF) may consist of conduction disorders, low-voltage areas, or fractionated potentials. High-density and resolution epicardial mapping (HDREM) approaches have been introduced to quantify and visualize electrophysiological properties of the atria. These approaches are essential for obtaining innovative insights into arrhythmogenic substrates and identifying novel targets for therapy.

Biological Variation of Hemostasis Analytes in Atrial Fibrillation Patients Using Dabigatran.

Background: Analytical criteria for laboratory analysis based on biological variation are considered state-of-the-art. While biological variance should ideally be measured in patient populations for whom the tests are relevant, data are mostly only available from healthy individuals. We determined the biological variance of activated partial thromboplasmin time (APTT), prothrombin time (PT), fibrinogen, and trough dabigatran levels in patients with atrial fibrillation (AF) who were treated with dabigatran.

Unraveling the architecture of major histocompatibility complex class II haplotypes in rhesus macaques.

The regions in the genome that encode components of the immune system are often featured by polymorphism, copy number variation, and segmental duplications. There is a need to thoroughly characterize these complex regions to gain insight into the impact of genomic diversity on health and disease. Here we resolve the organization of complete major histocompatibility complex (MHC) class II regions in rhesus macaques by using a long-read sequencing strategy (Oxford Nanopore Technologies) in concert with adaptive sampling.

Exploring Diet-Based Treatments for Atrial Fibrillation: Patient Empowerment and Citizen Science as a Model for Quality-of-Life-Centered Solutions.

Atrial fibrillation (AF) is the most common heart rhythm disorder in the Western world. Between the years 2010 and 2019, the global prevalence of AF rose from 33.5 million to 59 million, highlighting the importance of developing equitable treatments for patients.

Is CRT Optimization Obsolete? A Referral Center's Experience.

Background: Cardiac resynchronization therapy (CRT) is a well-established therapy for patients with heart failure (HF). However, 30% of HF patients do not show any improvement in clinical status after CRT implantation. In this study, we report our echocardiography-based CRT optimization methodology, in daily practice at our CRT referral center.

Identification of Critical Slowing of Conduction Using Unipolar Atrial Voltage and Fractionation Mapping.

Background: Ablation strategies targeting fractionated or low-voltage potentials have been widely used in patients with persistent types of atrial fibrillation (AF). However, recent studies have questioned their role in effectively representing sites of conduction slowing, and thus arrhythmogenic substrates.

Objectives: The authors studied the relationship between local conduction velocity (CV) and the occurrence of fractionated and/or low-voltage potentials in order to identify areas with critically slowing of conduction.

Antihypertensive Drugs for the Prevention of Atrial Fibrillation: A Drug Target Mendelian Randomization Study.

Background: We investigated the potential impact of antihypertensive drugs for atrial fibrillation (AF) prevention through a drug target Mendelian randomization study to avoid the potential limitations of clinical studies.

Methods: Validated published single-nucleotide polymorphisms (SNPs) that mimic the action of 12 antihypertensive drug classes, including alpha-adrenoceptor blockers, adrenergic neuron blockers, angiotensin-converting enzyme inhibitors, angiotensin-II receptor blockers, beta-adrenoceptor blockers, centrally acting antihypertensive drugs, calcium channel blockers, loop diuretics, potassium-sparing diuretics and mineralocorticoid receptor antagonists, renin inhibitors, thiazides and related diuretic agents, and vasodilators were used. We estimated, via their corresponding gene and protein targets, the downstream effect of these drug classes to prevent AF via systolic blood pressure using 2-sample Mendelian randomization analyses.

Distinct Substrates of Idiopathic Ventricular Fibrillation Revealed by Arrhythmia Characteristics on Implantable Cardioverter-Defibrillator.

Background: Idiopathic ventricular fibrillation (IVF) can be associated with undetected distinct conditions such as microstructural cardiomyopathic alterations (MiCM) or Purkinje (Purk) activities with structurally normal hearts.

Objectives: This study sought to evaluate the characteristics of recurrent VF recorded on implantable defibrillator electrograms, associated with these substrates.

Methods: This was a multicenter collaboration study.

A Singular-Value-Based Map to Highlight Abnormal Regions Associated With Atrial Fibrillation Using High-Resolution Electrograms and Multi-Lead ECG.

Objective: The severity of atrial fibrillation (AF) can be assessed from intra-operative epicardial measurements (high-resolution electrograms), using metrics such as conduction block (CB) and continuous conduction delay and block (cCDCB). These features capture differences in conduction velocity and wavefront propagation, but ignore complementary properties such as the morphology of the action potentials. In this work, we focus on such complementary properties, and derive features to detect variations in the atrial potential waveforms.

Conduction Velocity and Anisotropic Properties of Fibrillation Waves During Acutely Induced and Long-Standing Persistent AF.

Background: Quantified features of local conduction heterogeneity due to pathological alterations of myocardial tissue could serve as a marker for the degree of electrical remodeling and hence be used to determine the stage of atrial fibrillation (AF).

Objectives: In this study, the authors investigated whether local directional heterogeneity (LDH) and anisotropy ratio, derived from estimated local conduction velocities (CVs) during AF, are suitable electrical parameters to stage AF.

Methods: Epicardial mapping (244-electrode array, interelectrode distance 2.

Robotic-Assisted Epicardial Hybrid Ablation and Left Appendage Closure in Persistent Atrial Fibrillation: First European Experience.

Pulmonary vein isolation is currently considered to be the gold standard for ablating paroxysmal atrial fibrillation. However, its efficacy is limited in patients with persistent atrial fibrillation. The convergent procedure has emerged as a hybrid ablation.

Identification of Atrial Transmural Conduction Inhomogeneity Using Unipolar Electrogram Morphology.

(1) Background: Structural remodeling plays an important role in the pathophysiology of atrial fibrillation (AF). It is likely that structural remodeling occurs transmurally, giving rise to electrical endo-epicardial asynchrony (EEA). Recent studies have suggested that areas of EEA may be suitable targets for ablation therapy of AF.

The Role of Immune Cells Driving Electropathology and Atrial Fibrillation.

Atrial fibrillation (AF) is the most common progressive cardiac arrhythmia worldwide and entails serious complications including stroke and heart failure. Despite decades of clinical research, the current treatment of AF is suboptimal. This is due to a lack of knowledge on the mechanistic root causes of AF.

Long-Term Outcomes of Cardiac Resynchronization Therapy in Patients With Repaired Tetralogy of Fallot: A Multicenter Study.

Background: A growing number of patients with tetralogy of Fallot develop left ventricular systolic dysfunction and heart failure, in addition to right ventricular dysfunction. Although cardiac resynchronization therapy (CRT) is an established treatment option, the effect of CRT in this population is still not well defined. This study aimed to investigate the early and late efficacy, survival, and safety of CRT in patients with tetralogy of Fallot.

Behavioral, physiological, and genetic drivers of coping in a non-human primate.

Animals experience stressful situations, from predation to social conflicts, but mostly deal with them successfully. This adaptive mechanism, coping, reduces the adverse effects of stressors, and its failure may result in reduced fitness. Substantial inter-individual variation in coping is observed, yet little is known about how behavioral, physiological and genetic drivers regulate coping holistically and contribute to such variations.

Burden of cardiometabolic disorders and lifetime risk of new-onset atrial fibrillation among men and women: the Rotterdam Study.

Aims: To examine the association between the burden of cardiometabolic disorders with new-onset atrial fibrillation (AF) and lifetime risk of AF incidence among men and women.

Methods And Results: Four thousand one hundred and one men and 5421 women free of AF at baseline (1996-2008) from the population-based Rotterdam Study were included. Sex-specific Cox proportional-hazards regression models were used to assess the association between the burden of cardiometabolic disorders and risk of new-onset AF.

Biatrial arrhythmogenic substrate in patients with hypertrophic obstructive cardiomyopathy.

Background: Atrial fibrillation (AF) in patients with hypertrophic obstructive cardiomyopathy (HOCM) may be caused by a primary atrial myopathy. Whether HOCM-related atrial myopathy affects mainly electrophysiological properties of the left atrium (LA) or also the right atrium (RA) has never been investigated.

Objective: The purpose of this study was to characterize atrial conduction and explore differences in the prevalence of conduction disorders, potential fractionation, and low-voltage areas (LVAs) between the RA and LA during sinus rhythm (SR) as indicators of potential arrhythmogenic areas.

Preclinical Models of Cardiac Disease: A Comprehensive Overview for Clinical Scientists.

For recent decades, cardiac diseases have been the leading cause of death and morbidity worldwide. Despite significant achievements in their management, profound understanding of disease progression is limited. The lack of biologically relevant and robust preclinical disease models that truly grasp the molecular underpinnings of cardiac disease and its pathophysiology attributes to this stagnation, as well as the insufficiency of platforms that effectively explore novel therapeutic avenues.

The repertoire of a West African chimpanzee population is characterized by limited gene, allele, and haplotype variation.

Introduction: The killer cell immunoglobulin-like receptors (KIR) play a pivotal role in modulating the NK cell responses, for instance, through interaction with major histocompatibility complex (MHC) class I molecules. Both gene systems map to different chromosomes but co-evolved during evolution. The human gene family is characterized by abundant allelic polymorphism and copy number variation.

Biomechanical response of ultrathin slices of hypertrophic cardiomyopathy tissue to myosin modulator mavacamten.

Hypertrophic cardiomyopathy (HCM) is the most common inherited myocardial disorder of the heart, but effective treatment options remain limited. Mavacamten, a direct myosin modulator, has been presented as novel pharmacological therapy for HCM. The aim of this study was to analyze the biomechanical response of HCM tissue to Mavacamten using living myocardial slices (LMS).