Circadian Variation in QT Dispersion Determined from a 12‐Lead Holter Recording: A Methodological Study of an Age‐ and Sex‐Stratified Group of Healthy Subjects

Abstract

Selection of leads is of crucial importance for repetitive measurements of QT dispersion. Circadian variation was detected in subjects over 50 years of age, when all 12 or only the 6 precordial leads were taken into account.

QT Intervals and QT Dispersion Determined from a 12‐Lead 24‐Hour Holter Recording in Patients with Coronary Artery Disease and Patients with Heart Failure

“…We have previously demonstrated, 15 that measurement every fourth hour during the 24‐hour period is sufficient to demonstrate a circadian variation of QT dispersion in healthy subjects. Each measurement was performed every fourth hour comprising 10 consecutive measurements of QT maximum and QT minimum.…”

“…These studies vary in selection of leads and timing of measurements and therefore the results are difficult to compare. We have in a methodological study demonstrated that lead selection and sample length influence circadian variation of QT dispersion 15 …”

Circadian and Gender Effects on Repolarization in Healthy Adults: A Study Using Harmonic Regression Analysis

“…Batur et al studied circadian variation in QTc-dispersion in subjects with coronary artery disease compared to controls and found a significant circadian variation in QTc-dispersion in the coronary artery disease subgroup. 27 Hansen et al reported a circadian variation in QT-dispersion in healthy subjects 13 and in a subsequent analysis showed that while a circadian variation in QT-dispersion exists in healthy subjects and those with coronary artery disease, it was absent in those who had a prior myocardial infarction or heart failure. 14 Ishida et al studied healthy subjects with 24-hour ambulatory monitoring and found QT-dispersion values were greatest during the day (1-5 PM), and lowest at night (1-5 AM), reaching statistical significance.…”

“…Alternatively, dispersion of the QT-interval has been previously proposed as a marker for the regional differences in repolarization 6 and prior studies have shown gender and age differences in this marker. [7][8][9] A circadian variation in repolarization has been previously reported, [10][11][12][13][14] and the cycle-by-cycle variability in ventricular repolarization has been found to be lower during the night and exhibits a peak shortly after awakening in the morning. 15 However, previous studies of circadian variation in ventricular repolarization have not used harmonic regression analysis, a published technique used in modeling variation throughout a 24-hour cycle.…”

Cardiac conductive disturbance in patients with polycystic ovary syndrome

“…Gonadal steroid disorders can change the electrocardiogram (ECG) morphology [12,13], but the effects of PCOS on ECGs are not fully elucidated.…”