QT Interval Determinant

QT Interval and QT Variability

Measurement of the QT interval.

Ventricular repolarization is reflected by the T-wave of the surface electrocardiogram, the QT interval being the time taken for ventricular recovery. QT measurement has assumed clinical importance as prolongation is associated with a variety of conditions includingthe Romano-Ward' and JervellLange-Neilson syndromes, drug toxirity' and an adverse prognosis following acute myocardial infarction....

QT interval in anorexia nervosa.

OBJECTIVES To determine the incidence of a long QT interval as a marker for sudden death in patients with anorexia nervosa and to assess the effect of refeeding. To define a long QT interval by linear regression analysis and estimation of the upper limit of the confidence interval (95% CI) and to compare this with the commonly used Bazett rate correction formula. DESIGN Prospective case contr...

Beyond a prolonged QT interval

A 14-year-old girl was admitted with generalized tonic-clonic convulsions for 2min along with tongue biting. Her family reported previous recurrent attacks of muscle cramps and carpo-pedal spasms of four months’ duration prior to admission but they had never previously sought medical help. The patient had a good appetite and no diarrhea, with no prior history of cardiovascular disease or sympto...

Issues in QT interval measurement

The QT interval, apart from clinical implications is crucial for safety assessment of new drugs under development. A QTc prolongation of even 10 msec in a study group is a warning signal for a new drug. There are various issues involved in the measurement of the QT interval especially regarding the ending of the T wave and different morphological pattern of T-U complex. The other issue is signi...