OBJECTIVES Exercise-induced QT/RR hysteresis exists when, for a given R-R interval, the QT interval duration is shorter during recovery after exercise than during exercise. We sought to assess the association between QT/RR hysteresis and imaging evidence of myocardial ischemia. BACKGROUND Because ischemia induces cellular disturbances known to decrease membrane action potential duration, we h...

BACKGROUND AND PURPOSE Body core temperature (Tc) changes affect the QT interval, but correction for this has not been systematically investigated. It may be important to correct QT intervals for drug-induced changes in Tc. EXPERIMENTAL APPROACH Anaesthetized beagle dogs were artificially cooled (34.2 degrees C) or warmed (42.1 degrees C). The relationship between corrected QT intervals (QTcV...

BACKGROUND Hypothyroidism can manifest with cardiac abnormalities, often consisting of a combination of morphologic and functional changes. Low voltage, sinus bradycardia, and slowed conduction are usually found on electrocardiography.There are few reports of occurrence of torsades de pointes as the first presentation of long QT syndrome in the course of hypothyroidism. CASE PRESENTATION In p...

The cardiac delayed rectifier potassium current mediates repolarization of the action potential and underlies the QT interval of the ECG. Mutations in either of the two molecular components of the rapid delayed rectifier (I(K,r)), HERG and KCNE2, have been linked to heritable or acquired long-QT syndrome. Mechanisms whereby mutations of KCNE2 produce fatal cardiac arrhythmias characteristic of ...

how to cite this article: movahedian ah, heidarzadeh arani m, motaharizad m, mousavi gha, mosayebi z. evaluation of qt dispersion in children with breath holding spells. iran j child neurol. winter 2016; 10(1):25-30. abstract objective breath holding spells (bhs) are common involuntary reflexes in infancy and early childhood. differential diagnosis should embrace long qt syndrome (lqts) and par...

To the Editor: The QT-RR interval relationship is too complex to be described by using simple correction factors. Because the regulatory and commercial impact of even minor errors in drug studies can be far reaching, these correction factors have come under scrutiny. The letter by Dr Barbey, “Vardenafil-Associated QTc Changes: Not Merely a Normal Autonomic Process,” emphasizes the important poi...

BACKGROUND AND PURPOSE Early identification of patients at risk of angiographic vasospasm after aneurysmal subarachnoid hemorrhage (SAH) may mitigate its sequelae. One mechanism that may contribute to angiographic vasospasm is increased central sympathetic activity, which is also thought to cause electrocardiographic (ECG) changes after SAH. Here, we perform the first study to determine the ass...

We would like to thank the authors for the letter [1] regarding our manuscript entitled “Prolonged Tp-e interval and Tp-e/QT correlates well with modified Rodnan skin severity score in patients with systemic sclerosis” [2] published in “Cardiology Journal”. We would also like to thank the Editor for the opportunity to respond to this letter. In the study we aimed to evaluate Tp-e interval and T...

BACKGROUND Cases of sudden death associated with sildenafil citrate use have been reported in men with coronary artery disease. The aim of this study was to investigate the drug's effect on cardiac repolarization and sinus autonomic and vascular control in men with mild chronic heart failure (CHF; New York Heart Association classification II). Changes in these variables could predispose patient...