Prolonged heart-rate adjusted QT intervals on the electrocardiogram (ECG) are associated with an increased risk for coronary heart disease and sudden death. However, the diagnosis of the prolonged QT interval is hampered by lack of standards. We studied variations in the prevalence of prolonged QT, based on different common definitions, in a large nonhospitalized population, and compared our re...

RATIONALE Recent literature emphasizes the utility of QT variability to study ventricular electrophysiologic function. In this investigation, we sought to test the hypothesis that beat-to-beat fluctuations in QT intervals are mediated by sympathetic activity in normal subjects using postural challenge and isoproterenol infusions. SUBJECTS AND METHODS We obtained ECG in the supine and standing...

We read with great interest the article by Bestas et al1 entitled “The effect of adrenaline on desflurane-induced prolonged QTc interval: a randomized double-blind trial”, which is published in the current issue of European Review for Medical and Pharmacological Sciences. The Authors1 investigated the effect of adrenaline on desflurane-induced prolonged corrected QT (QTc) interval. They mention...

Suggestions were made that increased myocardial sympathetic activity is reflected by elevated QT variability (dynamic changes in QT interval duration). However, the relationship between QT variability and the amount of norepinephrine released from the cardiac sympathetic terminals is unknown. We thus attempted to assess this relationship. The study was performed in 17 subjects (12 with major de...

P rolongation of the QT interval is a serious electrocardiogram finding because of its association with torsades de pointes and sudden cardiac death. Both congenital and acquired factors can lead to abnormal lengthening of the QT interval. Six types of congenital long QT syndrome (LQT1– LQT6) have been described, each involving mutations in genes encoding potassium or sodium transmembrane chann...

BACKGROUND AND PURPOSE Drug-induced prolongation of the QT interval can lead to torsade de pointes, a life-threatening ventricular arrhythmia. Finding appropriate assays from among the plethora of options available to predict reliably this serious adverse effect in humans remains a challenging issue for the discovery and development of drugs. The purpose of the present study was to develop and ...

The difference between the maximum and minimum QT interval measured from a 12-lead electrocardiogram was defined as an index of spatial inhomogeneous repolarization of the ventricular myocardium. The causal relationship between QT dispersion and incidence of ventricular arrhythmias has been pointed out in various heart diseases, but until now it was discussed mainly related to sinus rhythm. QT ...

AIM To determine the prevalence of QT prolongation in a large series of end stage liver disease (ESLD) patients and its association to clinical variables and mortality. METHODS The QT interval was measured and corrected for heart rate for each patient, with a prolonged QT cutoff defined as QT > 450 ms for males and QT > 470 ms for females. Multiple clinical variables were evaluated including ...

We describe an alternative approach to the prediction of W and Z transverse momentum distributions based on an extended version of the DDT formula. The resummation of large logarithms, mandatory at small qT, is performed in qT-space, rather than in the impact parameter b. The leading, next-to-leading and nextto-next-to-leading towers of logarithms are identical in the b-space and qT-space appro...

We report on an asymptomatic 10-year-old boy who had a short QT interval (corrected QT interval, 260 ms). Short QT syndrome (SQTS) was detected in a school screening program for heart disease and the patient was subsequently diagnosed as having N588K mutation in the KCNH2 gene. Quinidine prolonged the QT interval, but not the QU interval. During treadmill exercise stress test, QT and QU interva...