Analysis Of QT Interval Differences In Clinical Trials

Electrocardiograms (ECGs) are widely used for screening and monitoring heart ac-tivity, most heart problems can be identified or even diagnosed through observations of ECG wave aberrations.ECGs consists of P, Q, R, S, T waves, sometimes followed by a U-wave. Each wave represents certain heart activity. In the medical literature, people usually study the cardiac repolarization abnormalities and malignant arrhythmias through analyzing the single ECG wave forms or their relationship with each other. Among all these relationship, the QT interval is of particular interest to drug makers because the pro-longation of the QT interval may reflect cardiac safety problems. QT study was designed by QT interval measurement, assess the side effect of drug cause QT interval prolongation, and determine the risk of drug cause malignant arrhythmia. Comparisons of QTc through a linear mixed model were made to assess cardiovascular risk of drugs (Moxifloxation). Data from a study with108subjects participating in a two-period placebo-controlled cross-over trial with repeat ECGs obtained at baseline and12time points after inter-ventions.Conclusions:Moxifloxation to cause QTc interval prolongation is stronger than placebo(p<0.001).We further studied the difference of QTc in trial group and control group at different time points after intervention, increased time, time and other factors effect as the variables in the linear model, to estimate the overall difference of QTc be-tween the experimental group and the control group, and discusses the trend of variation with time about QTc in the two groups.