The 2023 Canadian Cardiovascular Society Clinical Practice Update on Management of the Patient With a Prolonged QT Interval.

A prolonged QT interval on the electrocardiogram is associated with an increased risk of the torsades de pointes form of ventricular arrhythmia resulting in syncope, sudden cardiac arrest or death, or misdiagnosis as a seizure disorder. The cause of QT prolongation can be congenital and inherited as an autosomal dominant variant, or it can be transient and acquired, often because of QT-prolonging drugs or electrolyte abnormalities. Automated measurement of the QT interval can be inaccurate, especially when the baseline electrocardiogram is abnormal, and manual verification is recommended.

Fontan Heart: Insight Into the Physiological Role of the Right Heart.

Background: Cardiac output (CO) is almost normal in children born without a functional right ventricle (RV), and a Fontan repair, so why is RV dysfunction such a clinical problem? We tested the hypotheses that increased pulmonary vascular resistance (PVR) is the dominant factor and volume expansion by any means is of limited benefit.

Methods: We removed the RV from a previously used MATLAB model and altered vascular volume, venous compliance (Cv), PVR, and measures of left ventricular (LV) systolic and diastolic function. CO and regional vascular pressures were the primary outcome measures.

A Validated Model for Sudden Cardiac Death Risk Prediction in Pediatric Hypertrophic Cardiomyopathy.

Background: Hypertrophic cardiomyopathy is the leading cause of sudden cardiac death (SCD) in children and young adults. Our objective was to develop and validate a SCD risk prediction model in pediatric hypertrophic cardiomyopathy to guide SCD prevention strategies.

Methods: In an international multicenter observational cohort study, phenotype-positive patients with isolated hypertrophic cardiomyopathy <18 years of age at diagnosis were eligible.

Cancer Risk in Congenital Heart Disease-What Is the Evidence?

As life expectancy in patients with congenital heart disease (CHD) has improved, the risk for developing noncardiac morbidities is increasing in adult patients with CHD (ACHD). Among these noncardiac complications, malignancies significantly contribute to the disease burden of ACHD patients. Epidemiologic studies of cancer risk in CHD patients are challenging because they require large numbers of patients, extended follow-up, detailed and validated clinical data, and appropriate reference populations.

Phenotypic Manifestations of Arrhythmogenic Cardiomyopathy in Children and Adolescents.

Background: Arrhythmogenic cardiomyopathy (ACM) is a variably penetrant disease increasingly identified in young patients.

Objectives: This study sought to describe the diverse phenotype, genotype, and outcomes in pediatric and adolescent patients.

Methods: Records from 1999 to 2016 were reviewed for individuals age <21 years with a consistent personal or family history.

SCN5A mutations in 442 neonates and children: genotype-phenotype correlation and identification of higher-risk subgroups.

Aims: To clarify the clinical characteristics and outcomes of children with SCN5A-mediated disease and to improve their risk stratification.

Methods And Results: A multicentre, international, retrospective cohort study was conducted in 25 tertiary hospitals in 13 countries between 1990 and 2015. All patients ≤16 years of age diagnosed with a genetically confirmed SCN5A mutation were included in the analysis.

Cardiac Events During Competitive, Recreational, and Daily Activities in Children and Adolescents With Long QT Syndrome.

Background: The 2005 Bethesda Conference Guidelines advise patients with long QT syndrome against competitive sports. We assessed cardiac event rates during competitive and recreational sports, and daily activities among treated long QT syndrome patients.

Methods And Results: Long QT syndrome patients aged ≥4 years treated with anti-adrenergic therapy were included.

Exposure to Low-Dose Ionizing Radiation From Cardiac Procedures in Patients With Congenital Heart Disease: 15-Year Data From a Population-Based Longitudinal Cohort.

Background: The burden of low-dose ionizing radiation (LDIR) exposure from medical procedures among individuals with congenital heart disease (CHD) is unknown. In this longitudinal population-based study, we sought to determine exposure to LDIR-related cardiac imaging and therapeutic procedures in children and adults with CHD.

Methods And Results: In an analysis of the Quebec CHD database, exposure to the following LDIR-related cardiac procedures was recorded: catheter-based diagnostic procedures, structural heart interventions, coronary interventions, computed tomography scans of the chest, nuclear procedures, and pacemaker/implantable cardioverter-defibrillator insertion and repair.

"Magnetic attraction" in the pediatric emergency department: the case of a malfunctioning implantable cardioverter-defibrillator.

The use of implantable cardioverter-defibrillators (ICDs) in pediatric patients has increased substantially over the past 3 decades. We report the case of a 15-year-old boy with congenital heart disease who presented with recurrent inappropriate ICD shocks due to a lead malfunction. Inaccessibility of a magnet to inactivate shock therapy in the pediatric emergency department (PED) resulted in numerous additional inappropriate shocks.