| Objective: To study the relationship between ventricular repolarization and the occurrence of ventricular arrhythmias in acute myocardial infarction(AMI).Method: Fifty-two patients with AMI and sixty control subjects served as the study population.They were examined by 24 h Holter monitoring. The computer analyzed the mean and standard deviation of QT interval and RR interval.we make the standard deviation of QT intervals as the QT variability(QTV),the standard deviation of normal RR intervals (SDNN) as the heart rate variability,the quotient of QTV and QT mean as the coefficient of QT variation(QTCV). The AMI group was divided into two groups: high risk of ventricular arrhythmia (VA) (Lown grade≥Ⅲgrade, A1 group of 22 patients), low-risk VA (Lown grade≤II level, A2 group of 30 patients).We analyzed the change of HRV,QTV,QTCV in two groups.Results1. QT interval and heart rate: In AMI group ,the mean of HR in 24h was notably lower(62.15±7.93bpm vs 77.37±10.84bpm,P<0.01), and QT was strikingly longer (408.71±40.80ms vs 387.72±27.21ms,P<0.01)compared with the control group, while the difference of QTc between two groups was not significant(412.40±25.11ms vs 404.50±28.62ms,P>0.05).2. In AMI group, QTV,QTCV and SDNN in 24h were markedly lower than the control group(20.03±9.91ms vs 29.95±7.27ms,P<0.01;0.056±0.03 vs 0.081±0.02,P<0.01;82.54±17.39 vs 141.30±22.21,P<0.01).3. QTV and HR were higher during the day than the night in two groups ,but QT mean and SDNN were less than the night. The differences were significan(t72.30±10.7 vs 59.78±8.73,P<0.05; 85.50±15.31 vs 70.62±9.21,P<0.05; 18.06±3.94 vs 13.51±4.81,P<0.05; 25.55±5.78 vs 20.16±4.79,P<0.05;382.62±28.71 vs 415.53± 30.16,P<0.05;361.09±25.14 vs 402.53±27.14,P<0.05; 65.92±26.07 vs 96.17±28.06,P<0.05; 128.63±28.03 vs 154.25±31.04,P<0.05)(72.30±10.70 vs 85.50±15.31 ,P>0.05; 59.78±8.73 vs 70.62±9.21,P>0.05; 382.62±28.71 vs 361.09±25.14 ,P>0.05;415.53±30.16 vs 402.53±27.14,P>0.05).4. HRV, QTV, and QTCV were significantly lower in the A1 group (68.34±19.72ms vs. 84.10±27.20ms, P <0.05; 15.68±4.96ms vs. 23.57±8.20ms, P <0.01; 0.043±0.014 vs. 0.063±0.023, P <0.01).Conclusion1. Not only in AMI group but also in the control group, HR,QT interval, QTV and SDNN shewed day-night rhythms.2. HRV,QTV and QTCV were significant in two groups by 24 hours Holter monitoring also . These indicators can better reflect automatic nervous activity at level of ventricular and damages of ventricular muscle. It is probably important value to predict ventricular arrhythmia and sudden death. |
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