Impact and Modifiers of Ventricular Pacing in Patients With Single Ventricle Circulation.

Background: Palliation of the single ventricle (SV) circulation is associated with a burden of lifelong complications. Previous studies have identified that the need for a permanent ventricular pacing system (PPM) may be associated with additional adverse long-term outcomes.

Objectives: The goal of this study was to quantify the attributable risk of PPM in patients with SV, and to identify modifiable risk factors.

Genotype Predicts Outcomes in Fetuses and Neonates With Severe Congenital Long QT Syndrome.

Objectives: This study sought to determine the relationship between long QT syndrome (LQTS) subtype (LTQ1, LTQ2, LTQ3) and postnatal cardiac events (CEs).

Background: LQTS presenting with 2:1 atrioventricular block or torsades de pointes in the fetus and/or neonate has been associated with risk for major CEs, but overall outcomes and predictors remain unknown.

Methods: A retrospective study involving 25 international centers evaluated the course of fetuses/newborns diagnosed with congenital LQTS and either 2:1 atrioventricular block or torsades de pointes.

External Cardioversion-Defibrillation with Pushing Down on the Chest Wall to Increase the Success Rate in Obese Patients.

BACKGROUND The energy delivered by a defibrillator is expressed in joules (J). However, current is what actually defibrillates the heart and is related to the voltage-to-impedance ratio. With the same energy, the lower the transthoracic impedance, the higher the current delivered.

Using coronary sinus ostium as the reference for the slow pathway ablation of atrioventricular nodal reentrant tachycardia in children.

Background: Successful slow pathway (SP) ablation sites for atrioventricular nodal reentrant tachycardia (AVNRT) are usually located inside the Koch's triangle (KT). This study aimed to determine the ablation site of SP using the coronary sinus (CS) ostium (CSO) as the reference and to evaluate the efficacy of the CSO-guided SP ablation.

Methods: A regional geometry around the KT was constructed by 3D mapping in 52 consecutive patients under age 18 with AVNRT.

Possible Propofol-Induced Priapism Following Cardiac Catheter Ablation in a Teenager.

BACKGROUND Priapism is rarely reported as a potential complication after the cardiac ablation procedure. We report the case of a teenager admitted for atrial flutter ablation who developed priapism following the procedure. CASE REPORT A 16-year-old male with episodic atrial flutter came to our hospital for an electrophysiological study and catheter ablation.

Asymptomatic Idiopathic Belhassen Ventricular Tachycardia in a Neonate Detected Using 'Smart Sock' Wearable Smartphone-Enabled Cardiac Monitoring.

BACKGROUND Wearable smartphone-enabled cardiac monitoring devices can aid the diagnosis of asymptomatic tachycardia in neonates and infants. This report is of a rare case of left posterior fascicular ventricular tachycardia of Belhassen type detected in a neonate by 'smart sock' cardiac monitoring. CASE REPORT A premature baby boy at 37 weeks gestational age was discharged home after three days without complication, and was given 'smart socks' to wear.

Senning Procedure for Physiological Atrial Inversion With Left Atrial Isomerism.

We present the case of an infant with left atrial isomerism with complex pulmonary and systemic venous connections that resulted in physiological parallel circulation in the setting of ventriculoarterial concordance who was surgically treated using the Senning procedure. This case highlights a rare cause for cyanosis due to poor mixing from a parallel circulation and an issue with nomenclature. ().

What have we learned in the last 20 years? A comparison of a modern era pediatric and congenital catheter ablation registry to previous pediatric ablation registries.

Background: Since the onset of pediatric catheter ablation, the pediatric electrophysiology community has reported outcomes via various registries (PAPCA [Prospective Assessment After Pediatric Cardiac Ablation], PCAR [Pediatric Catheter Ablation Registry]). Most recently, a modern era pediatric and congenital ablation registry (MAP-IT [Multicenter Pediatric and Congenital EP Quality Initiative]) was developed for eventual incorporation into the National Cardiovascular Data Registry (NCDR) IMPACT (Improving Pediatric and Adult Congenital Treatment) registry.

Objective: The purpose of this study was to describe initial findings from the MAP-IT pilot registry and to compare these findings to earlier registries.

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.

Acquired and congenital coronary artery abnormalities.

Sudden unexpected cardiac deaths in approximately 20% of young athletes are due to acquired or congenital coronary artery abnormalities. Kawasaki disease is the leading cause for acquired coronary artery abnormalities, which can cause late coronary artery sequelae including aneurysms, stenosis, and thrombosis, leading to myocardial ischaemia and ventricular fibrillation. Patients with anomalous left coronary artery from the pulmonary artery can develop adequate collateral circulation from the right coronary artery in the newborn period, which remains asymptomatic only to manifest in adulthood with myocardial ischaemia, ventricular arrhythmias, and sudden death.

High Output Cardiac Failure Resolving after Repair of AV Fistula in a Six-Month-Old.

Background. Acquired AVF in pediatrics are commonly caused by iatrogenic means, including arterial or venous punctures. These fistulae can cause great hemodynamic stress on the heart as soon as they are created.

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.

Long-term follow-up of a pediatric cohort with short QT syndrome.

Objectives: The purpose of this study was to define the clinical characteristics and long-term follow-up of pediatric patients with short QT syndrome (SQTS).

Background: SQTS is associated with sudden cardiac death. The clinical characteristics and long-term prognosis in young patients have not been reported.

Dysfunctional potassium channel subunit interaction as a novel mechanism of long QT syndrome.

Background: The slowly-activating delayed rectifier current IKs contributes to repolarization of the cardiac action potential, and is composed of a pore-forming α-subunit, KCNQ1, and a modulatory β-subunit, KCNE1. Mutations in either subunit can cause long QT syndrome, a potentially fatal arrhythmic disorder. How KCNE1 exerts its extensive control over the kinetics of IKs remains unresolved

Objective: To evaluate the impact of a novel KCNQ1 mutation on IKs channel gating and kinetics

Methods: KCNQ1 mutations were expressed in Xenopus oocytes in the presence and absence of KCNE1.

Low recurrence rate in treating atrioventricular nodal reentrant tachycardia with triple freeze-thaw cycles.

Background: Cryoablation is an alternative to radiofrequency ablation in treating atrioventricular nodal reentrant tachycardia (AVNRT). However, its long-term effectiveness is in question when compared to radiofrequency ablation. We reviewed the results of cryoablation in children with AVNRT at our institute.

Quality of life and psychosocial functioning of children with cardiac arrhythmias.

Childhood cardiac arrhythmias may have a long-lasting impact on a family and typically require long-term medical follow-up. Whereas some arrhythmias are benign, others can be life threatening and require significant medical care. As with many chronic illnesses, it is important to study the potential psychosocial effects of childhood arrhythmias and how they may impact a child's quality of life.

Congenital long QT 3 in the pediatric population.

There is insufficient knowledge concerning long-QT (LQT) 3 in the pediatric population to determine whether recommendations for more aggressive therapy in these patients are appropriate. An international multicenter review of 43 children with cardiac sodium channel (SCN5A) mutations and clinical manifestations of LQT syndrome without overlap of other SCN5A syndromes was undertaken to describe the clinical characteristics of LQT3 in children. Patients were aged 7.

Safety and results of cryoablation in patients <5 years old and/or <15 kilograms.

Current recommendations discourage elective radiofrequency ablation in patients <5 years old and/or weighing <15 kg, primarily because of the greater complication rate. To describe the current use, complications, and immediate outcomes of cryoablation in this patient population, a multicenter retrospective review of all patients <5 years old and/or weighing <15 kg who were treated with cryoablation for arrhythmia was performed. Eleven centers contributed data for 68 procedures on 61 patients.

Focal atrial tachycardia originating from the donor superior vena cava after bicaval orthotopic heart transplantation.

An 11-year-old boy, who underwent bicaval orthotopic heart transplantation for idiopathic dilated cardiomyopathy, had a focal atrial tachycardia originating from the donor superior vena cava. The pathogenesis of this tachycardia may be related to transplant rejection or transplant vasculopathy. Radiofrequency catheter ablation can eliminate this unique tachycardia and result in hemodynamic improvement.

Short QT syndrome in a pediatric patient.

Short QT syndrome (SQTS) is a recently described genetic syndrome characterized by abnormally brisk ventricular repolarization. Similar to long QT syndrome, SQTS might result in ventricular arrhythmias, syncope, and sudden death. The clinical diagnosis of SQTS is supported by the finding of an abnormally short QT interval on the resting electrocardiogram in combination with a suggestive clinical or family history.

The most common site of success and its predictors in radiofrequency catheter ablation of the slow atrioventricular nodal pathway in children.

Background: Locating ablation targets on the slow pathway in children as one would in adults may not accommodate the dimensional changes of Koch's triangle that occur with heart growth. We investigated the most common site of success and the effect of a variety of variables on the outcome of slow pathway ablation in children.

Methods: A total of 116 patients (ages 4-16 years) with structurally normal hearts underwent radiofrequency ablation of either the antegrade or the retrograde slow pathway.