Objective To explore TWA detection method in electrocardiogram records based on dynamic time-domain method and TWA value for predicting malignant ventricular arrhythmia in patients with DCM.Methods This study included 86 hospitalized patients with DCM during 2006~2008 at Lishui City Central Hospital.According to the type of ventricular arrhythmia,they were divided into malignant ventricular arrhythmia group(28 cases) and non-malignant ventricular arrhythmia group(58 cases).Using time-domain measurement of TWA index,the sensitivity,specificity for TWA index predicting malignant ventricular arrhythmias were analyzed.Results TWA in non-malignant ventricular arrhythmia group and malignant ventricular arrhythmias group was significant difference(P<0.01).When we used Talt ≥7.6μV to predict malignant ventricular arrhythmias in patients with DCM,the sensitivity was 86%,specificity was 83%,positive predictive value was 71%,negative predictive value was 92%.Conclusions Time-domain measurement of TWA in patients with DCM for malignant ventricular arrhythmia has a predictive value.