Holter Recordings at Initial Assessment for Long QT Syndrome: Relationship to Genotype Status and Cardiac Events.

Background: The relationship of Holter recordings of repolarization length to outcome in long QT syndrome (LQTS) is unknown. Methods: Holter recordings and initial 12 lead ECG QTc were related to outcome in 101 individuals with LQTS and 28 gene-negative relatives. Mean QTc (mQTc) and mean RTPc (R-wave to peak T-wave, mRTPc) using Bazett correction were measured, analyzing heart rates 40 to 120 bpm.

Normative Heart-Rate Corrected Values for Repolarisation Length From Holter Recordings in Children and Adults.

Background: Normative values for heart-rate corrected repolarisation length are not available in children and are scarce in adults. We wished to define repeatability and normative values of Holter recording measurements of repolarisation length in healthy individuals using a commercially available system, and compare measurements with those from 12-lead electrocardiograms (ECGs).

Methods: Twenty-four-hour (24-) Holter recordings were made on 99 Healthy volunteers: 52 children (7 months to 14 years) and 47 adults (≥15 yrs).

Physical and Psychological Consequences of Left Cardiac Sympathetic Denervation in Long-QT Syndrome and Catecholaminergic Polymorphic Ventricular Tachycardia.

Background: Left cardiac sympathetic denervation reduces risk in long-QT syndrome (LQTS) and catecholaminergic polymorphic ventricular tachycardia. Side effects and patient satisfaction have not been systematically analyzed in patients who underwent left cardiac sympathetic denervation. Aims of this study included documenting physical and psychological consequences and patient satisfaction after left cardiac sympathetic denervation in LQTS or catecholaminergic polymorphic ventricular tachycardia.

Array comparative genomic hybridization identifies a heterozygous deletion of exon 3 of the RYR2 gene.

Background: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a heritable cardiac disorder characterized by life-threatening ventricular tachycardia caused by exercise or acute emotional stress. The standard diagnostic screening involves Sanger-based sequencing of 45 of the 105 translated exons of the RYR2 gene, and copy number changes of a limited number of exons that are detected using multiplex ligation-dependent probe amplification (MLPA).

Methods: In the current study, a previously validated bespoke array comparative genomic hybridization (aCGH) technique was used to detect copy number changes in the RYR2 gene in a 43-year-old woman clinically diagnosed with CPVT.

Array comparative genomic hybridization identifies a heterozygous deletion of the entire KCNJ2 gene as a cause of sudden cardiac death.

Background: Large gene rearrangements, not detectable by standard molecular genetic sequencing techniques, are present in a minority of patients with long QT syndrome. We aimed to screen for large rearrangements in genes responsible for long QT syndrome as part of the molecular autopsy of a 36-year-old woman who died suddenly and had a negative autopsy. A retrospective analysis of an ECG identified a long QT interval, but sequencing of known LQT genes was uninformative.

Symptoms and signs associated with syncope in young people with primary cardiac arrhythmias.

Background: It is often reported that clinical symptoms are useful in differentiating cardiac from non-cardiac syncope. Studies in the young are rare. This study was designed to capture the symptoms and signs reported by patients with cardiac syncope before the patients or their attending clinicians knew the final diagnosis.

Identification of large gene deletions and duplications in KCNQ1 and KCNH2 in patients with long QT syndrome.

Background: Sequencing or denaturing high-performance liquid chromatography (dHPLC) analysis of the known genes associated with the long QT syndrome (LQTS) fails to identify mutations in approximately 25% of subjects with inherited LQTS. Large gene deletions and duplications can be missed with these methodologies.

Objective: The purpose of this study was to determine whether deletions and/or duplications of one or more exons of the main LQTS genes were present in an LQTS mutation-negative cohort.

Brugada syndrome masquerading as febrile seizures.

Fever can precipitate ventricular tachycardia in adults with Brugada syndrome, but such a link has not been reported in children. A 21-month-old white girl presented repeatedly with decreased conscious level and seizures during fever. During a typical episode, rapid ventricular tachycardia was documented.