In the interesting article by Viskin et al., adenosine-induced bradycardia was found to produce a higher increase in QT and a lower decrease in QTc (calculated using the Bazett formula) in subjects with long-QT syndrome (LQTS) than in controls. However, a major issue in this study concerns the reliability of QT correction when large ranges of heart rates are analysed. The Bazett formula overcor...

OBJECTIVES To improve the diagnostic criteria of the congenital long QT syndrome in borderline cases we examined rate adaptation of ventricular repolarization phases during exercise and subsequent recovery in children with the long QT syndrome and controls. METHODS Nineteen children with definite long QT syndrome and 19 healthy controls underwent exercise testing. QT intervals were measured t...

introduction: prolongation of qt interval might result in dangerous cardiac arrhythmias, including torsades de pointes (tdp), consequently leading to syncope or death. a limited number of studies carried out in this respect to date have shown that qt interval might increase during pregnancy. on the other hand, it has been shown that each pregnancy might result in an increase in the risk of card...