The Association between QT Dispersion-QT Dispersion Ratio and the Severity-Extent of Coronary Artery Disease in Patients with Stable Coronary Artery Disease

Abstract

To evaluate QT dispersion in patients admitted with suspicion of coronary artery disease (CAD) and to study the association between QT parameters and the extent and severity of CAD. Methods: Prospective study, recording electrocardiograms at 50 mm/s in patients with and without CAD. Single-blind analysis for QT parameter and angiography scoring measurements. Results are expressed as QT dispersion (QTd), corrected QT dispersion (QTcd), the QT dispersion ratio (QTdR), and vessel and Gensini scores for the evaluation of CAD extent-severity. Results: QTd, QTcd, and QTdR were all higher in patients with CAD than without CAD (58.9±14.6 msec vs 32.9±10.8 msec, 63.2±15.5 msec vs 35.0±10.7 msec, 68.3±18.7 msec vs 37.7±12.5 msec; p<0.001, p<0.001, p<0.001, respectively). QTd, QTcd, and QTdR values had a tendency to increase significantly from the 1-vessel toward 3-vessel disease group (50.71±15.02 msec vs 60.03±13.24 msec vs 70.91±7.02 msec, 53.54±15.04 msec vs 64.41±14.06 msec vs 76.68±7,10 msec and 57.04±17.06 msec vs 69.53±16.77 msec vs 83.54±12.64 msec, respectively, in 1-, 2-, and 3-vessel disease groups). Gensini score was also significantly correlated with QTd, QTcd, and QTdR (p<0.001, p<0.001, p<0.001, respectively). Conclusion: QT parameter increases in patients with CAD than those with normal coronary arteries may provide important information in our clinical practice. The regression analysis showed that the main factor affecting QTd, QTcd, and QTdR is the Gensini score-in other words, the extent and severity of CAD.