Long-QT founder variant T309I-Kv7.1 with dominant negative pattern may predispose delayed afterdepolarizations under β-adrenergic stimulation.

The variant c.926C > T (p.T309I) in KCNQ1 gene was identified in 10 putatively unrelated Czech families with long QT syndrome (LQTS).

Cardiac profile of the Czech population of Duchenne muscular dystrophy patients: a cardiovascular magnetic resonance study with T1 mapping.

Background: The progressive cardiomyopathy that develops in boys with Duchenne and Becker muscular dystrophy (DMD/BMD) is presumed to be a secondary consequence of the fibrosis within the myocardium. There are only limited data on using parametric imaging in these patients. The purpose of this study was to assess native T1 and extracellular volume (ECV) values in DMD patients.

Out-of-Hospital Cardiac Arrest Due to Ventricular Fibrillation in a 5-Year-Old Pediatric Patient.

Out-of-hospital cardiac arrest in pediatric population is rare and predominantly has respiratory aetiology. Authors present the relatively unique case of out-of hospital cardiac arrest in 5-years old pediatric patient due to ventricular fibrillation (VF) as the initial rhythm during the advanced life support. The patient was resuscitated by his parents and the initial rhythm was VF.

Long-term results of paediatric radiofrequency catheter ablation: a population-based study.

Aims: We aimed to evaluate long-term utilization and results of paediatric radiofrequency catheter ablation (RFCA) in a population-based study.

Methods And Results: Data from all three centres performing paediatric RFCA for the whole population of the Czech Republic between 1993 and 2010 were retrospectively reviewed. A total of 708 ablation procedures in 633 consecutive patients <18 years for 716 different substrates were tracked, with accessory pathways = 439 (61.

Electrophysiologic profile and results of invasive risk stratification in asymptomatic children and adolescents with the Wolff-Parkinson-White electrocardiographic pattern.

Background: Data on the results and clinical effect of an invasive risk stratification strategy in asymptomatic young patients with the Wolff-Parkinson-White electrocardiographic pattern are scarce.

Methods And Results: Eighty-five consecutive patients aged<18 years with a Wolff-Parkinson-White pattern and persistent preexcitation at maximum exercise undergoing invasive risk stratification were retrospectively studied. Adverse accessory pathway (AP) properties were defined according to currently consented criteria as any of the following: shortest preexcited RR interval during atrial fibrillation/rapid atrial pacing≤250 ms (or antegrade effective refractory period≤250 ms if shortest preexcited RR interval was not available) or inducible atrioventricular re-entrant tachycardia.

Clinical characteristics of 30 Czech families with long QT syndrome and KCNQ1 and KCNH2 gene mutations: importance of exercise testing.

Background: Classic symptoms of long QT syndrome (LQTS) include prolongation of QT interval on electrocardiograph, syncope, and cardiac arrest due to a distinctive form of polymorphic ventricular tachycardia, known as Torsade de Pointes. We assessed occurrence of LQTS signs in individuals from 30 Czech families with mutations in KCNQ1 and KCNH2 genes.

Methods And Results: One hundred five individuals from 30 Czech families with LQTS were genotyped for KCNQ1 and KCNH2.

Clinical characteristics and mutational analysis of the RyR2 gene in seven Czech families with catecholaminergic polymorphic ventricular tachycardia.

Background: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a rare hereditary arrhythmia. The onset of clinical symptoms usually occurs during childhood, and is typically related to exercise. The aim of our study was to describe the clinical characteristics of seven Czech families with CPVT and the results of mutational analysis of the RyR2 gene in these families.

Normal limits for heart rate as established using 24-hour ambulatory electrocardiography in children and adolescents.

Background: To the best of our knowledge, normal limits of heart rate with respect to gender, and as established using 24-hour ambulatory Holter electrocardiography, have yet to be published for the entire age range of children and adolescents.

Objectives: To establish the normal limits for heart rate in newborns, infants, children, and adolescents of both genders.

Patients And Methods: We obtained 24-hour Holter recordings from 616 healthy subjects aged from birth to 20 years with structurally normal hearts.