Objective:To assess the relationship between QT dispersion and the grades of ventricular arrhythmias (VA). To make clear the factors affecting QTd and the clinical significance. Methods:QTd in 100 patients with all kinds of VA were measured on the surface simultaneous 12-lead electrocardiogram. All the patients were followed. Results:QTd of patients with VA above Lown grades Ⅲ was significantly higher than that below. Logistic multiple regression analysis between patients with increased QTd and without

including syncope

grades of VA

causes of VA

and ST-T changes in the ECGs showed that the grades of VA and the ST-T changes in the ECGs were independently associated with QT dispersion. Of the 15 cases of syncope

8 directly caused by cardiovascular disease had a higher mean value of QTd than that of other cases. There were no significant differences in QTd between two recordings in 40 patients with VA in comparison with those between normal controls. Conclusion:QT dispersion may well be a useful tool to evaluate the severity of ventricular arrhythmias. QT dispersion may be closely related to the changes of pathophysiology in myocardial ischemia. QT dispersion may help to judge the cause of syncope.