ObjectiveTo explore the relationship of the fragmented QRS (fQRS) and the fQRS time limit with ventricular arrhythmia in old myocardial infarction (OMI) patients through contrasting the incidence of ventricular arrhythmia in OMI patients whether fQRS or not and ventricular arrhythmia in different fQRS time limit.MethodsAccording to the routine electrocardiogram,321 OMI patients were divided into group A (fQRS appearance,167 cases) and group B(fQRS non-appearance,154 cases).The lead with fQRS extense was ehosen and traced another 50 mm/s electrocardiogram,and 3 consecutive fQRS time limit were measured and them average was taken in group A.According to the fQRS time limit,the patients in group A were divided into 3 groups: group X( ≤0.100 s,96 cases),group Y (0.101-0.119 s,54 cases) and group Z( ≥0.120 s,17 cases).All the patients were continuously monitored with 24 hours dynamic electrocardiogram,and the incidence of ventricular arrhythmia was analyzed.ResultsThe incidence of ventricular arrhythmia in group A [ 78.4％ ( 131/167 ) ] was higher than that in group B [ 63.6％(98/154) ] (P＜ 0.01 ).The incidence of premature ventricular contraction(PVC) ＞ 720/24 hours in group A [ 28.7％(48/167 ) ] was higher than that in group B[ 17.5％(27/154) ] (P ＜ 0.05 ).The incidence of multifocal PVC,coupled PVC,nonsustained ventricular tachycardia and Lown 3-5 grades PVC was 16.2％ (27/167),33.5％ (56/167),12.0％ (20/167),34.1％ (57/167) in group A,7.8％ (12/154),21.4％ (33/154),4.5％(7/154),23.4％(36/154) in group B,there were significant differences between two groups (P＜ 0.05 ).The incidence of ventricular arrhythmia in group Z [ 100.0％( 17/17 ) ] was significantly higher than that in group Y [79.6％(43/54)] and group X [74.0％(71/96)](P＜ 0.05).The incidence of Lown 3-5 grades PVC in group Z[ 70.6％( 12/17 )] was significantly higher than that in group Y[ 42.6％(23/54)] and group X [ 22.9％(22/96) ],and the incidence of Lown 3-5 grades PVC in group Y was significantly higher than that in group X (P＜ 0.05).ConclusionsOMI patients with fQRS have higher incidence and severe degree in ventricular arrlhythmia than those without fQRS.With the fQRS time limit widened,PVC and Iown 3-5 grades PVC significantly increased.So fQRS is a new predicting index of OMI,and fQRS time limit has definite value in predicting the heart event for OMI patients.