BACKGROUND A short QT interval, within which an increased risk for atrial fibrillation and/or fatal cardiac arrhythmias occurs, has been difficult to define. METHODS The lower percentiles of a new QTc formula were determined, using a precise mathematical fitting of the QT-heart rate relationship from the ECGs of 13,600 individuals from the NHANES II and III surveys. RESULTS The QTc interval...

OBJECTIVE Children with Congenital Central Hypoventilation Syndrome (CCHS) have cardiovascular symptoms consistent with the autonomic nervous system dysregulation/dysfunction (ANSD) phenotype. We hypothesized that children with CCHS would have a relationship between PHOX2B genotype and two clinically applicable cardiovascular measures of ANSD: duration of longest r-r interval and longest correc...

BACKGROUND Although many electrocardiographic abnormalities have been reported previously, prolonged QTC interval represented as the most important ECG finding in patients with liver cirrhosis. Echocardiography can detect structural cardiac abnormalities in cirrhotic patients. OBJECTIVES The present study aimed to determine the correlation between QTC prolongation and echocardiographic findin...

OBJECTIVES To evaluate whether reduced heart rate variability (HRV), prolonged corrected QT (QTc) interval, or increased QT dispersion (QTD) are predictors of mortality in the general diabetic and nondiabetic population. RESEARCH DESIGN AND METHODS Nondiabetic (n = 1,560) and diabetic (n = 160) subjects aged 55-74 years were assessed to determine whether reduced HRV, prolonged QTc interval, a...

In this issue of the Journal, Zhang et al. (Am J Epidemiol. 2011;174(4):403-411) make a substantial contribution to research in the area of hormonal influences on cardiac repolarization by demonstrating an inverse association between testosterone levels and the Bazett's adjusted QT interval (QTc) and RR-adjusted QT interval in men but not in postmenopausal women. They suggest that testosterone ...

BACKGROUND We examined the effects of the various sleep stages on RR and QT intervals in healthy subjects and tested the hypothesis that there is a differential effect of sleep stage on QT interval in women compared with men. METHODS AND RESULTS Eighteen healthy subjects (9 women, age 22 to 45 years) underwent polysomnography and simultaneous recording of ECG, blood pressure, and respiration....

Objective Prolonged QT interval predisposes to ventricular arrhythmias and sudden cardiac death. However, the association between QT interval and mortality by the level of pre-existing kidney function has not been investigated. Methods We followed 6565 participants from the National Health and Nutrition Examination Survey III for a median of 13.3 years. Sample divided according to corrected Q...

The effect of lenalidomide on the corrected QT (QTc) interval was evaluated in healthy men and extended to patients based on the lenalidomide concentration-QTc (C-QTc) relationship. A rigorous assessment of the effect of lenalidomide on QTc intervals was conducted in healthy volunteers who each received, in randomized order, a single oral dose of 10 mg lenalidomide, 50 mg lenalidomide, 400 mg m...

INTRODUCTION AND OBJECTIVES The QT interval on the electrocardiogram has been shown to be longer in patients with systemic lupus erythematosus (SLE) compared to that of the general population. The clinical significance of this finding is unknown. The aim of this study was to assess the relationship between QT interval and subclinical atherosclerosis, measured by carotid-femoral pulse-wave veloc...

Analysis of QT interval from repeated recordings was made in 56 patients with documented idiopathic mitral valve prolapse (IMVP). The results were compared with a control of 62 healthy volunteers in whom mitral valve prolapse was excluded by both phonocardiography and echocardiography and with two other standard populations, those of Simonson and co-workers and of Ashman. After correction for a...