Objective:To study the relationship between QT dispersion and severe ventricular arrhythmias.Methods:of 128 patients diagnosed as coronary heart diseasec (CHD), the severe ventricular arrhythmiae was detected by electrocardiogram in 48 patients and the unsevere ventricular arrhythmias was detected in 46 patients. Their QTd were measured and compared with the control group 34 patients with wronary heart disease, but without ventricular arrhythmias.Results:QTd was especially prolbyged in severe ventricular arrhythmia group than those in control group (P