A meta-analysis of ECG data from healthy male volunteers: diurnal and intra-subject variability, and implications for planning ECG assessments and statistical analysis in clinical pharmacology studies

Abstract

The spontaneous variability in QTc measurements must be taken into account when designing studies and interpreting analyses of ECG data. The categorical analysis of QTc change of 30-60 ms is unlikely to be of any additional value to analyses of central tendency. For standard early clinical pharmacology studies, QTcF should be chosen as the primary correction method, while the mean of three measures taken in the afternoon and evening of Day-1 and pre-dose Day 1 should provide a reliable and representative baseline assessment.

Mortality prior to, during and after opioid maintenance treatment (OMT): A national prospective cross-registry study

“…The exercise test further indicated the changes in QTc interval that can occur with increased heart rate . Results of our cardiac investigations illustrate diurnal fluctuations of the QTc interval (Harris & Steare, 2006) . Three patients without LQTS mutations detected, had reductions to their QTc interval from above to significantly below 500 msec with increased heart rate, illustrating the reverse frequency-dependent effect of drug-induced QTc prolongation ).…”

“…The results of the cardiac investigations illustrate the diurnal fluctuations of the QTc interval. 114 In this study we recorded 24 hour ECGs, in which QTc intervals varied between markedly prolonged to below or down to 500 msec for all of the six patients.…”

Patients with Metabolic Syndrome Have Prolonged Corrected QT Interval (QTc)

“…The Bazett formula is commonly applied to adjust QT interval for heart rate, considering the interval is underestimated at low heart rate and overestimated at fast heart rate with the Bazett formula, we also adopted the Fridericia formula. 16 The JTc has been proposed as a more appropriate measure of ventricular repolarization than QTc when QRS duration is ≥120 ms. 17 The JTc was derived simply by subtracting the QRS duration from QTcB. The cut off value of QTcB is 430 ms for men and 450 ms for women.…”

Combining wearable physiological and inertial sensors with indoor user localization network to enhance activity recognition

“…Consequently, as you imagine, there is a lot of variability on the body postures that a single participants can assume, just think on the way that you are sitting on the sofa watching TV, or you are lying on the bed. Additionally, vital signs (like ECG), because of their nature, are affected of intra-and inter-subject variations [17]. The peculiarity of this work is to perform the activity in a real house with real furniture, not in a simulated environment.…”