The Predictive Value Of Tp-e/QT Ratio For Ventricular Arrhythmia In Patients With Acute ST-elevation Myocardial Infarction

Objective:Explore the immediate Tp-e/QT ratio and its change both preoperative and postoperative in patients with acute ST-elevation myocardial infarction(STEMI), count ventricular arrhythmias events occurred, and investigate the predictive value in order to guide clinical treatment better.Method:We collected153patients with STEMI undergoing emergency percutaneous coronary intervention(PCI) from the second hospital of Tianjin medical university hospital in May2011to August2012as observation group;there are95man and58women,the average age is62.31±12.57; there are73cases whose infarction relative artery (IRA) is anterior descending、31cases whose IRA is left circumflex and49cases whose IRA is right coronary artery. Choose92healthy subjects confirmed by electrocardiogram、cardiac ultrasound and coronary artery angiography (CAG) as normal control group, there are55man and37women,the average age is55.39±13.33. Measure QT interval and distance of Tpeak to Tend interval (Tp-e) in STEMI patients when they are admitted to hospital and after PCI immediately and healthy subjects when they are admitted to hospital and after CAG immediately; we choose the biggest Tp-e of IRA related to lead as transmural dispersion of repolarization (TDR), and also choose the biggest Tp-e in healthy subjects. Record age、gender、hypertension、diabetic、the peak of myocardial damage degree (CK-MB cTnI)、cardiac function (Killip classification、left ventricular ejection fraction (LVEF)、left ventricular end-diastolic dimension (LVEDD)、interventricular septal thickness (IVST)、left ventricular posterior wall (LVPW)and ST segment resolution(STR). Then record112STEMI patients with Holter monitoring electrocardiogram in the second day after PCI,the results are include24h standard deviation of RR interval (SDNN), ventricular arrhythmia is confirmed by Lown grading, then they can be divided into MVA(39cases) and non-MVA group (73cases). We use SPSS17.0to analysis; Measurement data use normality test (K-S method), measurement data with normal distribution use mean standard deviation, count data use percentage or frequency, measurement data between the two groups use independent sample t test, the comparison between the two pairs use paired t test, correlation between two variables use bivariate correlation the interaction between a variable and multiple variables use partial correlation analysis.; difference was considered statistically significant when P<0.05.Results:1. The immediate Tp-e/QT ratio comparison between observation group and control group admitted to hospital:the immediate Tp-e/QT ratio in control group admitted to hospital is0.23±0.09(n=92), and the immediate Tp-e/QT ratio in observation group admitted to hospital is0.31±0.16(n=153), which is higher than control group (P<0.05); SDNN in STEMI patients is221.70±46.87ms, and the correlation coefficient between SDNN and Tp-e/QT ratio is-0.253(P<0.05), which suggested that the correlation between Tp-e/QT ratio and the heart rate variability is negative.2. The Tp-e/QT ratio comparison between the control group and observation group during preoperative and postoperative:Tp-e/QT ratio in control group during preoperative is0.23±0.09(n=92),Tp-e/QT ratio in control group during postoperative is0.22±0.11, there is no statistical significance (P>0.05); Tp-e/QT ratio in observation group during preoperative is0.31±0.16(n=153), Tp-e/QT ratio in observation group during postoperative is0.25±0.07, there is a statistical significance (P<0.05).3. The relationship between the changes of Tp-e/QT ratio in control group during pre-or postoperative and the multiple clinical factors in observation group:there is no statistical significance between the change of Tp-e/QT ratio and age> gender hypertension、diabetic、myocardial damage degree (CK-MB cTn1)、cardiac function (Killip classification)、left ventricular ejection fraction (LVEF)、left ventricular end-diastolic dimension (LVEDD)、interventricular septal thickness (IVST)、left ventricular posterior wall (LVPW)(P>0.05), while there is significantly correlation between the change of Tp-e/QT and ST segment resolution (STR)(r=0.3357, P<0.05). 4. The Tp-e/QT ratio comparison between non-MVA and MVA group in control group admitted to hospital:the Tp-e/QT ratio in non-MVA group is0.29±0.09(n=73), and the Tp-e/QT ratio in MVA group is0.34±0.11(n=39), which is higher than non-MVA (P<0.05).Conclusion:1. The Tp-e/QT ratio in acute STEMI patients is higher than healthy subjects, which suggested it correlated with autonomic nervous function;2. The Tp-e/QT ratio is reduced in acute STEMI patients with PCI relatively to the patients admitted immediately,but it is not easy to return to normality, it is one of the reasons in organic heart disease;3. There is significantly positive correlation between the change of Tp-e/QT ratio and ST segment resolution (STR);4. The Tp-e/QT ratio is related to the MVA incidence of patients with acute STEMI,and the higher the Tp-e/QT ratio is, the higher incidence of MVA is.