Ventricular Depolarization Abnormalities and Their Role in Cardiac Risk Stratification - A Narrative Review.

Ventricular depolarization refers to the electrical activation and subsequent contraction of the ventricles, visible as the QRS complex on a 12-lead electrocardiogram (ECG). A well-organized and efficient depolarization is critical for cardiac function. Abnormalities in ventricular depolarization may indicate various pathologies and can be present in all leads if the condition is general, or in a subgroup of anatomically contiguous leads if the condition is limited to the corresponding anatomic location of the heart.

International Multicenter Cohort Study on Beta-Blocker-Free Treatment Strategies for Catecholaminergic Polymorphic Ventricular Tachycardia Patients.

Background: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a rare, potentially life-threatening genetic heart disease. Nonselective beta-blockers (BBs) are highly effective in reducing CPVT-triggered arrhythmic events. However, some patients suffer from unacceptable BB side effects and might require strategies without a BB.

Tilt training as a treatment for reflex syncope: a multimodal approach!?

Purpose: Reflex syncope is a burdensome disease with considerable repercussions on the quality of life. Tilt training is a therapeutic option, but evidence on this topic is scarce and outdated. Hyperventilation is oftentimes associated with reflex syncope.

Left ventricular hypertrophy: do not forget Fabry disease. Diagnostic work-up and differential diagnosis.

Background: Left ventricular (LV) hypertrophy is a common clinical finding. Differential diagnosis includes Fabry disease, a rare and progressive, but treatable storage disease caused by deficiency of α-galactosidase A. However, diagnosis of Fabry is often hampered by its clinical heterogeneity, LV hypertrophy phenocopies and unawareness of the clinician.

Serial Cardiac Magnetic Resonance Imaging in Patients with Mitral Valve Prolapse-A Single-Center Retrospective Registry.

Mitral valve prolapse (MVP) and mitral annular disjunction (MAD) are common valvular abnormalities that have been associated with ventricular arrhythmias (VA). Cardiac magnetic resonance imaging (CMR) has a key role in risk stratification of VA, including assessment of late gadolinium enhancement (LGE). Single-center retrospective analysis of patients with MVP or MAD who had >1 CMR and >1 24 h Holter registration available.

An international multicenter cohort study on implantable cardioverter-defibrillators for the treatment of symptomatic children with catecholaminergic polymorphic ventricular tachycardia.

Background: Catecholaminergic polymorphic ventricular tachycardia (CPVT) may cause sudden cardiac death (SCD) despite medical therapy. Therefore, implantable cardioverter-defibrillators (ICDs) are commonly advised. However, there is limited data on the outcomes of ICD use in children.

Reduced Ejection Fraction in Elite Endurance Athletes: Clinical and Genetic Overlap With Dilated Cardiomyopathy.

Background: Exercise-induced cardiac remodeling can be profound, resulting in clinical overlap with dilated cardiomyopathy, yet the significance of reduced ejection fraction (EF) in athletes is unclear. The aim is to assess the prevalence, clinical consequences, and genetic predisposition of reduced EF in athletes.

Methods: Young endurance athletes were recruited from elite training programs and underwent comprehensive cardiac phenotyping and genetic testing.

Flecainide Is Associated With a Lower Incidence of Arrhythmic Events in a Large Cohort of Patients With Catecholaminergic Polymorphic Ventricular Tachycardia.

Background: In severely affected patients with catecholaminergic polymorphic ventricular tachycardia, beta-blockers are often insufficiently protective. The purpose of this study was to evaluate whether flecainide is associated with a lower incidence of arrhythmic events (AEs) when added to beta-blockers in a large cohort of patients with catecholaminergic polymorphic ventricular tachycardia.

Methods: From 2 international registries, this multicenter case cross-over study included patients with a clinical or genetic diagnosis of catecholaminergic polymorphic ventricular tachycardia in whom flecainide was added to beta-blocker therapy.

Effectiveness of the risk stratification proposed by the 2022 European Heart Rhythm Association Expert Consensus statement on arrhythmic mitral valve prolapse.

Background: Recently, an expert consensus statement proposed indications where implantation of a primary prevention implantable cardioverter-defibrillator (ICD) may be reasonable in patients with mitral valve prolapse (MVP). The objective was to evaluate the proposed risk stratification by the expert consensus statement.

Methods: Consecutive patients with MVP without alternative arrhythmic substrates with cardiac magnetic resonance imaging (CMR) were included in a single-center retrospective registry.

Importance of exercise stress testing in evaluation of unexplained cardiac arrest survivor.

Background: In sudden cardiac arrest survivors without an immediately identifiable cause, additional extensive yet individualised testing is required.

Methods: We describe 3 survivors of sudden cardiac arrest in whom exercise stress testing was not performed during the initial hospital admission.

Results: All 3 patients were incorrectly diagnosed with long QT syndrome based on temporary sudden cardiac arrest-related heart rate-corrected QT interval prolongation, and exercise stress testing was not performed during the initial work-up.

Individualized QT interval (QTi) is a powerful diagnostic tool in long QT syndrome: results from a large validation study.

Aims: Diagnosis of Long QT syndrome (LQTS) is based on prolongation of the QT interval corrected for heart rate (QTc) on surface ECG and genotyping. However, up to 25% of genotype positive patients have a normal QTc interval. We recently showed that individualized QT interval (QTi) derived from 24 h holter data and defined as the QT value at the intersection of an RR interval of 1,000 ms with the linear regression line fitted through QT-RR data points of each individual patient was superior over QTc to predict mutation status in LQTS families.

Apical papillary muscle displacement is a prevalent feature and a phenotypic precursor of apical hypertrophic cardiomyopathy.

Aims: Papillary muscle (PM) abnormalities are considered part of the phenotypic spectrum of hypertrophic cardiomyopathy (HCM). The aim of this study was to evaluate the presence and frequency of PM displacement in different HCM phenotypes.

Methods And Results: We retrospectively analysed cardiovascular magnetic resonance (CMR) findings in 156 patients (25% females, median age 57 years).

A deep learning approach identifies new ECG features in congenital long QT syndrome.

Background: Congenital long QT syndrome (LQTS) is a rare heart disease caused by various underlying mutations. Most general cardiologists do not routinely see patients with congenital LQTS and may not always recognize the accompanying ECG features. In addition, a proportion of disease carriers do not display obvious abnormalities on their ECG.

An International Multicenter Cohort Study on β-Blockers for the Treatment of Symptomatic Children With Catecholaminergic Polymorphic Ventricular Tachycardia.

Background: Symptomatic children with catecholaminergic polymorphic ventricular tachycardia (CPVT) are at risk for recurrent arrhythmic events. β-Blockers decrease this risk, but studies comparing individual β-blockers in sizeable cohorts are lacking. We aimed to assess the association between risk for arrhythmic events and type of β-blocker in a large cohort of symptomatic children with CPVT.

Clinical characterization of the first Belgian SCN5A founder mutation cohort.

Aims: We identified the first Belgian SCN5A founder mutation, c.4813 + 3_4813 + 6dupGGGT. To describe the clinical spectrum and disease severity associated with this mutation, clinical data of 101 SCN5A founder mutation carriers and 46 non-mutation carrying family members from 25 Belgian families were collected.

An International Multicenter Evaluation of Inheritance Patterns, Arrhythmic Risks, and Underlying Mechanisms of -Catecholaminergic Polymorphic Ventricular Tachycardia.

Background: Genetic variants in calsequestrin-2 () cause an autosomal recessive form of catecholaminergic polymorphic ventricular tachycardia (CPVT), although isolated reports have identified arrhythmic phenotypes among heterozygotes. Improved insight into the inheritance patterns, arrhythmic risks, and molecular mechanisms of -CPVT was sought through an international multicenter collaboration.

Methods: Genotype-phenotype segregation in -CPVT families was assessed, and the impact of genotype on arrhythmic risk was evaluated using Cox regression models.

Transethnic Genome-Wide Association Study Provides Insights in the Genetic Architecture and Heritability of Long QT Syndrome.

Background: Long QT syndrome (LQTS) is a rare genetic disorder and a major preventable cause of sudden cardiac death in the young. A causal rare genetic variant with large effect size is identified in up to 80% of probands (genotype positive) and cascade family screening shows incomplete penetrance of genetic variants. Furthermore, a proportion of cases meeting diagnostic criteria for LQTS remain genetically elusive despite genetic testing of established genes (genotype negative).