| Objective We investigated fluctuations of ventricular-repolarization cycle length after single ventricular premature contraction (VPC) recorded in Holter electrocardiogram and characterised the fluctuations by a series of numerical parameters to compare the differences of the fluctuation between healthy adults and AMI patients and between high risk patients and low risk patients. Base on that, we try to establish a new method of risk stratification after AMI and explore its predictive value for identifying high-risk patients.Methods In this study, we propose a new risk stratification factor named ventricular repolarization turbulence (VRT) which means on the basic of sinus rhythm, a single VPC with compensatory-pause could affect the succedent consecutive ventricular repolarization process, presenting the fluctuation of ventricular repolarization cycle length. We chose 104 patients with AMI for 1-3 weeks as AMI group and 100 healthy adults as control group, detailed clinical data of these subjects were collected, AECG were undergone. We Segmented ventricular-repolarization interval J-T into five sections: J-Tb, J-Tp, J-Te, Tbp, Tpe, different segments express different electrophysiology significance, then measured and calculated 4 numerical parameters for every segment. The parameters are turbulence onset (TO), corrected turbulence onset (TOc), turbulence slope(TS), turbulence timing(TT). Thus we could get twenty indexes to describe the phenomenon of VRT. In addition, other known traditional risk factors such as left ventricular ejection fraction (LVEF), heart rate variability (HRV), mean heart rate(HR) and heart rate turbulence slope (HRT,RR-TS) were obtained by ultrasonic cardiogram (UCG) and AECG. Differences of above indexes were compared between AMI group and control group.Then patients with AMI were divided into high-risk group and low-risk group according to Killip cardiac funtional grading and whether or not complicating with malignant ventricular arrhythmia. After following-up, we compared indexes among subgroups which based on whether relapsing heart ischemia events, suffering malignant electrocardio abnormalities or events of following-up endpoints. Then confirmed the critical value of VRT-TS by statistics method, survival analysis was made to assess the value of predicting high-risk patients with AMI among the indexes of VRT and other traditional risk stratification factors.Results①VRT in AMI patients are obviously attenuated: JTp-TS , JTe-TS, Tbp-TS, Tpe-TS are lower than control group (p<0.05); JTp-TT, JTe-TO, Tpe-TO and JTb-TOc, JTp- TOc, JTe-TOc are adverse(p<0.05).②In subsets of AMI group, VRT of high risk patients are more weaker: JTe-TS (p<0.01) in group combined congestive heart failure;JTp-TS, JTe-TS (p<0.05, p<0.01) in group combined malignant ventricular arrhythmia are obviously lower than low-risk groups.③After following-up, VRT in patients who recurred heart event also attenuated significantly: AMI patients with recurred myocardial infarction or stenocardia are older (p<0.05), JTe-TS are lower (p<0.01); JTp-TS, JTe-TS, Tpe-TS in AMI patients with cardiac death or malignant arrhythmia are lower (p<0.05); AMI patients who suffered endpoint events of following-up are older, RR-TS, JTp-TS, Tpe-TS, JTe-TS are lower too (p<0.05).④VRT-TS was not correlated with age, HRT-TS and HR, but correlated with SDNN(p<0.05).⑤Statistical analyzing with Kaplan-Meier, the stratification critical values of JTp-TS, JTe-TS, Tpe-TS are 4.80, 5.68, 6.00(ms/RRI).⑥In Cox univariate analysis, SDNN, LVEF, RR-TS, JTp-TS, JTe-TS, Tpe-TS were influential factors in heart events; In Cox multivariate analysis, SDNN, JTe-TS had predictive values to heart events (p<0.05). JTe-TS have the best predicted worth(RR=2.82), SDNN are the next(RR=2.39).Conclusions VRT have better worth of identifying high-risk patients after AMI than other traditional indexes. It could serve as a potent and independent risk stratification factor of AMI patients.
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