Elucidation of as a Novel Long-QT Syndrome-Susceptibility Gene.

Background: Long-QT syndrome (LQTS) is characterized by QT prolongation and increased risk for syncope, seizures, and sudden cardiac death. The majority of LQTS stems from pathogenic mutations in , , or . However, ≈10% of patients with LQTS remain genetically elusive.

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.

Catecholaminergic polymorphic ventricular tachycardia patients with multiple genetic variants in the PACES CPVT Registry.

Background: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is often a life-threatening arrhythmia disorder with variable penetrance and expressivity. Little is known about the incidence or outcomes of CPVT patients with ≥2 variants.

Methods: The phenotypes, genotypes and outcomes of patients in the Pediatric and Congenital Electrophysiology Society CPVT Registry with ≥2 variants in genes linked to CPVT were ascertained.

The clinical and genetic spectrum of catecholaminergic polymorphic ventricular tachycardia: findings from an international multicentre registry.

Aims: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an ion channelopathy characterized by ventricular arrhythmia during exertion or stress. Mutations in RYR2-coded Ryanodine Receptor-2 (RyR2) and CASQ2-coded Calsequestrin-2 (CASQ2) genes underlie CPVT1 and CPVT2, respectively. However, prognostic markers are scarce.

Catecholaminergic polymorphic ventricular tachycardia in children: analysis of therapeutic strategies and outcomes from an international multicenter registry.

Background: Catecholaminergic polymorphic ventricular tachycardia is an uncommon, potentially lethal, ion channelopathy. Standard therapies have high failure rates and little is known about treatment in children. Newer options such as flecainide and left cardiac sympathetic denervation are not well validated.

KCNJ2 mutation causes an adrenergic-dependent rectification abnormality with calcium sensitivity and ventricular arrhythmia.

Background: KCNJ2 mutations are associated with a variety of inherited arrhythmia syndromes including catecholaminergic polymorphic ventricular tachycardia 3.

Objective: To characterize the detailed cellular mechanisms of the clinically recognized KCNJ2 mutation R67Q.

Methods: Kir2.

Just sinus bradycardia or something more serious?

An asymptomatic 5-year-old girl presented with bradycardia during a routine well-child visit. Further evaluation revealed profound sinus bradycardia, exercise-induced bidirectional ventricular tachycardia, and supraventricular tachycardia. An echocardiogram showed heavy trabeculations in the left ventricular myocardium.

Atrial Fibrillation and Long QT Syndrome Presenting in a 12-Year-Old Girl.

Atrial fibrillation (AF) is rare in the pediatric population; however, there is increasing recognition that AF can be inherited. Long QT syndrome (LQTS), likewise, can be both acquired and inherited with mutations leading to abnormalities in cardiac ion channel function. Mutations in KCNQ1 are the most common cause of LQTS.

In utero premature closure of the ductus arteriosus presenting as isolated right ventricular hypertrophy.

Background: The etiology of isolated right ventricular hypertrophy (RVH) is distinct from other forms of hypertrophic cardiomyopathy. RVH is typically seen in the setting of pulmonary valve stenosis or Tetralogy of Fallot. A rare cause of isolated RVH is premature closure of the patent ductus arteriosus (PDA) in utero that results in pulmonary hypertension.

Sudden cardiac death in young athletes: trying to find the needle in the haystack.

Sudden cardiac death in young athletes is an infrequent, but catastrophic event. Hypertrophic cardiomyopathy, coronary artery anomalies, and arrhythmias are common identifiable causes of sudden cardiac death. Many of these disorders can be difficult to diagnose, and athletes may be completely asymptomatic prior to their sudden death event.

Techniques to avoid atrioventricular block during radiofrequency catheter ablation of septal tachycardia substrates in young patients.

Unlabelled: Radiofrequency catheter ablation (RFCA) has proven safe for most young patients, but the risk of inadvertent atrioventricular (AV) block remains. The purpose of this report is to describe techniques to avoid inadvertent AV block during effective RFCA in young patients with septal tachycardia substrates.

Methods: The techniques included intubation and apnea during RFCA, coronary sinus pacing during RFCA to observe intact AV conduction during junctional ectopy, localizing the optimal His electrogram prior to RFCA, not ablating during tachycardia and titrating power output with temperature monitoring.