Multicenter cohort study on duration of antiarrhythmic medication for supraventricular tachycardia in infants.

Antiarrhythmic medication (AM) is commonly used to prevent supraventricular tachycardia (SVT) recurrence in infants. Our aim was to determine whether a shorter duration of AM is sufficient to prevent atrioventricular reentrant tachycardia (AVRT) recurrence and evaluate risk factors for recurrence of SVT after discontinued AM.This multicenter cohort study included all infants diagnosed with SVT in the five university hospitals in Finland between 2005 and 2017.

Familial Recurrence Patterns in Congenitally Corrected Transposition of the Great Arteries: An International Study.

Background: Congenitally corrected transposition of the great arteries (ccTGA) is a rare disease of unknown cause. We aimed to better understand familial recurrence patterns.

Methods: An international, multicentre, retrospective cohort study was conducted in 29 tertiary hospitals in 6 countries between 1990 and 2018, entailing investigation of 1043 unrelated ccTGA probands.

The rare Costello variant HRAS c.173C>T (p.T58I) with severe neonatal hypertrophic cardiomyopathy.

We report a 10-year-old girl presenting with severe neonatal hypertrophic cardiomyopathy (HCM), feeding difficulties, mildly abnormal facial features, and progressive skeletal muscle symptoms but with normal cognitive development. Targeted oligonucleotide-selective sequencing of 101 cardiomyopathy genes revealed the genetic diagnosis, and the mutation was verified by Sanger sequencing in the patient and her parents. To offer insights into the potential mechanism of patient mutation, protein structural analysis was performed using the resolved structure of human activated HRAS protein with bound GTP analogue (PDB id 5P21) in Discovery Studio 4.

Cardiovascular magnetic resonance findings in patients with PRKAG2 gene mutations.

Background: Autosomal dominantly inherited PRKAG2 cardiac syndrome is due to a unique defect of the cardiac cell metabolism and has a distinctive histopathology with excess intracellular glycogen, and prognosis different from sarcomeric hypertrophic cardiomyopathy. We aimed to define the distinct characteristics of PRKAG2 using cardiovascular magnetic resonance (CMR).

Methods: CMR (1.

Follow-up of 316 molecularly defined pediatric long-QT syndrome patients: clinical course, treatments, and side effects.

Background: Inherited long-QT syndrome (LQTS) is associated with risk of sudden death. We assessed the clinical course and the fulfillment of current treatment strategies in molecularly defined pediatric LQTS type 1 and (LQT1) and type 2 (LQT2) patients.

Methods And Results: Follow-up data covering a mean of 12 years were collected for 316 genotyped LQT1 and LQT2 patients aged 0 to 18 years.

Expanding the phenotype of Timothy syndrome type 2: an adolescent with ventricular fibrillation but normal development.

Timothy syndrome is a rare multiorgan disorder with prolonged QTc interval, congenital heart defects, syndactyly, typical facial features and neurodevelopmental problems. Ventricular tachyarrhythmia is the leading cause of death at early age. Classical Timothy syndrome type 1 (TS1) results from a recurrent de novo CACNA1C mutation, G406R in exon 8 A.

Population-based single-center outcome for pediatric catheter ablation of common supraventricular tachycardias.

Background: Catheter ablation has become the preferred treatment for common supraventricular tachycardia (SVT) in children and adolescents, but long-term follow-up data on pediatric patients remain limited.

Methods: To provide follow-up data, we created a population-based prospective pediatric catheter ablation registry in 1997. All patients underwent clinical follow-up at 1 month and 1 year after the procedure.

[Cryoablation in the treatment of cardiac arrhythmias].

Catheter ablation is currently the preferred treatment for various arrhythmias. Radiofrequency ablation has been shown to be efficacious and safe. Cryoablation provides better ablation catheter stability and reduces the risk of an inadvertent atrioventricular (AV) block when treating arrhythmia substrates near the normal conduction system.

Long-term performance of beat-to-beat automatic ventricular threshold adjustment in infants with congenital atrioventricular block.

Background: AutoCapture™ (AC) of St. Jude Medical (SJM; St. Paul, MN, USA) pacemakers provides beat-to-beat ventricular capture verification and allows low-amplitude pacing.

Permanent cardiac pacing in children: choosing the optimal pacing site: a multicenter study.

Background: We evaluated the effects of the site of ventricular pacing on left ventricular (LV) synchrony and function in children requiring permanent pacing.

Methods And Results: One hundred seventy-eight children (aged <18 years) from 21 centers with atrioventricular block and a structurally normal heart undergoing permanent pacing were studied cross-sectionally. Median age at evaluation was 11.

New mutation of mitochondrial DNAJC19 causing dilated and noncompaction cardiomyopathy, anemia, ataxia, and male genital anomalies.

Background: We report a new mutation in the human DNAJC19 gene that causes early onset dilated cardiomyopathy syndrome (DCMA).

Methods: Two brothers of Finnish origin presented with an unusual combination of early onset dilated cardiomyopathy syndrome, a disease which was associated with cardiac noncompaction, microcytic anemia, ataxia, male genital anomalies and methylglutaconic aciduria type V. Suspicion of a DCMA syndrome prompted sequencing of the human DNAJC19 gene.

Intravenous epinephrine infusion test in diagnosis of catecholaminergic polymorphic ventricular tachycardia.

Introduction: A test involving intravenous infusion of epinephrine has been proposed as a method alternative to exercise stress test in diagnosis of catecholaminergic polymorphic ventricular tachycardia (CPVT). We aimed at estimating the predictive value of intravenous epinephrine administration in CPVT patients with frequent exercise-induced ventricular ectopy.

Methods And Results: We recruited 81 subjects, including 25 CPVT-linked ryanodine receptor 2 (RYR2) mutation carriers, 11 genetically undefined CPVT patients, and 45 unaffected family members.

Impact of the permanent ventricular pacing site on left ventricular function in children: a retrospective multicentre survey.

Background: Chronic right ventricular (RV) pacing is associated with deleterious effects on cardiac function.

Objective: In an observational multicentre study in children with isolated atrioventricular (AV) block receiving chronic ventricular pacing, the importance of the ventricular pacing site on left ventricular (LV) function was investigated.

Methods: Demographics, maternal autoantibody status and echocardiographic measurements on LV end-diastolic and end-systolic dimensions and volumes at age <18 years were retrospectively collected from patients undergoing chronic ventricular pacing (>1 year) for isolated AV block.

Junctional ectopic tachycardia after surgery for congenital heart disease: incidence, risk factors and outcome.

Objectives: Junctional ectopic tachycardia (JET) is a serious, haemodynamically compromising tachyarrhythmia associated with paediatric cardiac surgery, with a reported mortality up to 14%. The incidence, risk factors and outcome of this tachyarrhythmia were evaluated in this population-based, case-control patient cohort.

Methods: A total of 1001 children, who underwent open-heart surgery during a 5-year period, were retrospectively analysed.

Catecholaminergic polymorphic ventricular tachycardia.

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited arrhythmogenic disorder that causes syncopal episodes related with stress or emotion and even sudden cardiac deaths. Signs and symptoms usually begin in childhood. A suspicion of CPVT should be kept in mind when a child or an adolescent suddenly loses consciousness, particularly if this happens upon physical exercise or sudden mental stress.

Automatic atrial threshold measurement and adjustment in pediatric patients.

Background: Automatic threshold measurement and output adjustment are used as default settings in modern pacemakers. The purpose of the study was to assess Atrial Capture Management (ACM) of Medtronic pacemakers in pediatric patients.

Methods: Forty children were enrolled in two centers.

Automatic ventricular threshold measurement in children with epicardial pacing leads.

Background: The aim of the study was to evaluate the safety and reliability of automatic ventricular pacing threshold measurement, the Medtronic Capture Management (CM), in children with epicardial pacing leads. CM has not been recommended for use with epicardial leads due to lack of pertinent data.

Methods: During a 2-year study period, 34 children (mean age 6.