Homogeneity of recovery time protects against arrhythmias whereas dispersion of recovery time is arrhythmogenic. A single surface electrocardiographic QT interval gives no information on recovery time dispersion but the difference between the maximum and minimum body surface QT interval may be relevant. This hypothesis was tested by measuring the dispersion of the corrected QT interval (QTc) in...

BACKGROUND Although sudden cardiac death (SCD) is heritable, its genetic underpinnings are poorly characterized. The QT interval appears to have a graded relationship to SCD, and 35% to 45% of its variation is heritable. We examined the relationship among recently reported common genetic variants, QT interval, and SCD. METHODS AND RESULTS We genotyped 15 common (minor allele frequency >1%) ca...

AIMS The identification of affected family members with long QT syndrome (LQTS) is often difficult due to their normal-or only marginally lengthened-QT interval duration. We examined whether physical exercise test could increase the ability to detect the mutation carrier status in phenotypically normal LQTS family members. METHODS AND RESULTS Sixty-six subjects were included: 15 were carriers...

Torsades de pointes is a rare but potentially lethal arrhythmia which mainly occurs in the setting of a prolonged QT interval. ECG is a reliable tool to detect such abnormalities, routinely taken from all patients over 40 who undergo surgery. We describe the case of a 35-year-old woman with torsades de points arrhythmia after hysterectomy surgery. Most likely, our patients had long QT syndro...

For half a century, the relationship between the QT interval and cardiac arrhythmias has been recognized,1 although attention has focused primarily on prolongation of the QT. The congenital long-QT syndrome (LQTS) was first identified in patients with syncope, aborted sudden death, or family history of cardiac arrest as an association between a prolonged QT interval and development of potential...

Abnormal left ventricular structure and function as in, for example, left ventricular hypertrophy or chronic heart failure, is associated with sudden cardiac death and, when the ejection fraction is depressed, with prolongation of the QT interval. The dependence on heart rate of QT interval prolongation in these conditions, and the relationship of any abnormalities either to deranged autonomic ...

Among childhood psychiatric disorders, attention deficit hyperactivity disorder (ADHD) is of greatest interest to practitioners. Methylphenidate (MPH) is a drug that is widely used in the treatment of children in whom ADHD has been diagnosed. Although this treatment has been used for years, its effects on the heart remain the subject of debate. The QT interval comprises the ventricular activati...

INTRODUCTION Objective of this study was to determine the optimal (most heritable) phenotype for gene finding studies of QT interval in the general population. We also studied the extent to which heritability of QT interval can be explained by genes that also influence resting heart rate. METHODS AND RESULTS Subjects in this classic twin study were 105 monozygotic and 256 dizygotic female twi...