AIMS The long QT syndrome is mainly defined by QT interval prolongation (QTc > 0.44s). However, data obtained in genotyped patients showed that resting QTc measurement alone may be inaccurate for ascertaining the phenotype. The aim of this study was to evaluate the diagnostic performance of QT interval rate-dependence in untreated chromosome 11-linked patients. METHODS The study population co...

BACKGROUND SCN5A encodes the alpha-subunit (Na(v)1.5) of the principle Na(+) channel in the human heart. Genetic lesions in SCN5A can cause congenital long QT syndrome (LQTS) variant 3 (LQT-3) in adults by disrupting inactivation of the Na(v)1.5 channel. Pharmacological targeting of mutation-altered Na(+) channels has proven promising in developing a gene-specific therapeutic strategy to manage...

BACKGROUND The purpose of this study was to determine whether scintigraphic evidence of cardiac sympathetic neuronal dysinnervation is present in patients with the familial long QT syndrome. The "sympathetic imbalance" hypothesis for the familial long QT syndrome proposes that the long QT syndrome results from a congenital imbalance of sympathetic innervation of the heart caused by lower-than-n...

BACKGROUND Although the incidence of ventricular tachyarrhythmias associated with structural heart disease is highest in winter and during the daytime, seasonal and circadian variations among cardiac events in patients with congenital long QT syndrome (LQTS) remain unknown. The present study aims to determine seasonal and circadian cardiac events in patients with a congenital LQTS genotype. M...

Background: Long QT syndrome (LQTS) is characterized by the prolongation of QT interval, which results in syncope and sudden cardiac death in young people. KCNQ1 is the most common gene responsible for this syndrome. Methods: Molecular investigation was performed by DNA Sanger sequencing in Iranian families with a history of syncope. In silico examinations were performed for predicting the path...

background: cardiovascular mortality and morbidity are high in chronic renal failure (crf) patients. increased dispersion of qt intervals is known to predispose to ventricular arrhythmias and sudden cardiac death. this study was conducted to assess the effect of hemodialysis (hd) on corrected qt (qtc) intervals and their dispersions (qtd) in chronic hemodialyzed patients. methods: fifty-eight p...

Background. Erythromycin is known to prolong ventricular repolarization and has been associated with the occurrence of torsades de pointes. In this study, we have investigated potential mechanisms in vivo and in vitro for induction of an acquired long QT syndrome by erythromycin. Methods and Results. Ventricular electrograms and endocardial monophasic action potentials were recorded in anesthet...

Introduction The Long QT syndrome (LQTS) can be inherited or acquired and is of particular interest and concern at present. Patients with LQTS are predisposed to the ventricular tachyarrhythmia torsade de pointes (TdP) which causes syncope and sudden death. Inherited LQTS is the prototype of the "primary cardiac arrhythmias" or "cardiac ion channelopathies". The study of inherited LQTS has prov...

Department of Biology, National Taiwan Normal University, Taipei; Department of Internal Medicine, Chang Gung Memorial Hospital and Chang Gung University, Taipei; Department of Internal Medicine, Wei Gong Memorial Hospital, Tou Fen, Miaoli; Division of Cardiology, Department of Medicine, Veterans General Hospital-Taipei; and Department of Medical Research and Education, Veterans General Hospita...

Congenital long QT syndrome (LQTS) is a hereditary cardiac disease characterized by a prolongation of the QT interval at basal ECG and by a high risk of life-threatening arrhythmias. Disease prevalence is estimated at close to 1 in 2,500 live births. The two cardinal manifestations of LQTS are syncopal episodes, that may lead to cardiac arrest and sudden cardiac death, and electrocardiographic ...