To evaluate whether heart-rate-induced changes of the QT interval are dependent on autonomic tone, we studied 13 healthy subjects, mean age 67.5 years. The maximal uncorrected QT from leads I, II, V1 and V6 was determined during atrial pacing at 90 beats/min and 130 beats/min before and after i.v. administration of propranolol, 0.1 mg/kg, and atropine, 0.02 mg/kg. Significant reductions (p less...

The electrocardiogram was recorded for 100 seconds in 50 patients with atrial fibrillation to determine the relations between QT intervals and both the mean and instantaneous ventricular rates. The mean ventricular rate was 94 beats per minute with a mean QT interval of 357 ms. The mean QTc, corrected beat by beat with Bazett's formula, was 444 ms--longer than reported for sinus rhythm. Between...

Purpose: It is thought that arrhythmias are responsible for sudden deaths in patients with mitral valve prolapse (MVP). QT intervals may predict malignant arrhythmia potential in these patients. The aim of the present study is to assess QT variables in patients with MVP. Methods : We studied 46 patients with non-rheumatic, uncomplicated and isolated MVP and 25 healthy control subjects. All indi...

Electrophysiologic studies were performed in 15 patients with syncope and/or cardiac arrest who had the long QT syndrome and 11 control subjects who had normal QT intervals. The syndrome was familial in five patients and idiopathic in 10. All patients had a prolonged QT (546 +/- 68 msec, mean +/- SD) and corrected QT (550 +/- 51 msec). Incremental atrial pacing at cycle lengths of 600 to 400 ms...

In this paper, we will be concerned with the existence of renormalized solutions to following parabolic-elliptic system {?u ?t + Au = ?(u)|??|2 in QT ? (0, T), ?div(?(u)??) divF(u) QT, u 0 on ?? u(?, 0) u0 ?, where ?div a(x, t, u,?u) is a Leray-Lions operator defined inhomogeneous Orlicz-Sobolev space W1,x LM(QT) into its dual, M N-function related growth a. does not satisfy ?2-condition, and F...

The relationship between the location and size of an infarction and QT dispersion was investigated in 84 Japanese patients with chronic myocardial infarction (54 with anteroseptal infarction and 30 with inferior infarction). The control group consisted of 23 subjects without ischemic heart disease (13 normal subjects and 10 hypertensive patients). Corrected QT dispersion (maximum corrected QT i...

We present a case of drug-induced QT prolongation caused by an escitalopram overdose in a patient with previously undiagnosed congenital LQTS. A 15-year-old Caucasian female presented following a suicide attempt via an escitalopram overdose. The patient was found to have a prolonged QT interval with episodes of torsades de pointes. The patient was admitted to the telemetry unit and treated. Des...

Terfenadine and ketoconazole are the most widely used positive reference agents in non-clinical cardiac repolarization safety studies. The aim of the present study was to evaluate the effects of terfenadine, ketoconazole and their combination on QT prolongation using conscious guinea pigs. Conscious telemetered guinea pigs were orally administered terfenadine (50 mg/kg), ketoconazole (200 mg/kg...

This paper reviews recent developments in the physics of quantum turbulence (QT). QT was discovered in superfluid (4)He in the 1950s, while the research has taken a new direction since the middle of the 1990s. QT is comprised of quantized vortices that are definite topological defects and expected to give a prototype of turbulence much simpler than usual classical turbulence. We give a general ...

Prolongation of the QT interval can predispose to fatal ventricular arrhythmias. Differences in QT-labeling language can result in miscommunication and suboptimal risk mitigation. We systematically compared the phraseology used to communicate on QT-prolonging properties of 144 drugs newly approved (1st January 2006 to 1st June 2012) in the European Union (EU) and the United States (US), of whic...