Dispersion of QT Intervals – A Myth or a Diagnostic Symptom

Overview

Background.
QT interval dispersion (QTd) is conventionally interpreted as a result of repolarization heterogeneityin ventricular myocardium. However, another concept of QTd origin has been discussed recently, suggesting thatdifferent projections of the repolarization vector into individual ECG leads could be responsible for the differencesin QT interval duration. Moreover, the reproducibility could be influenced by factors both electrocardiographic (Twave amplitude, U wave) and extracardiac (noise, ECG measures). In the presented study we have followed the QTdin two groups of patients with proved changes of an electric heart field.Methods and Results. Studied groups: 1. Control group, 2. Healthy pregnant women, 3. Patients treated withdosulepine. QT interval was measured from 80 unipolar chest leads used for body surface potential mapping. TheQTdwas significantly higher in both experimental groups in comparison with the control group (p

Key words:
QT dispersion, vectorcardiography, dosulepine, body surface potential mapping.