| BackgroundAcute coronary syndrome(ACS)includes acute myocardial infarction(AMI)and unstable angina pectoris(UAP),and the former one is an important cause of death,including non-ST-segment elevation AMI(NSTEMI)and ST-segment elevation AMI(STEMI).Percutaneous coronary intervention(PCI)is one of the most effective strategies for ACS,but the cardiac function of patients after PCI may undergo different degrees of change or abnormalities,such as significantly prolonged or increased QT dispersion(QTd)and T peak-T end(Tp-Te)interval,reduced heart rate variability(HRV)and appearance of ischemic J wave or even huge J wave.Previous studies have shown that the above electrocardiograph(ECG)indicators or cardiac function parameters are closely related to adverse events of malignant ventricular arrhythmia(MVA)and sudden cardiac death(SCD).ObjectiveThis study was to observe the changes of QTd,HRV,Tp-Te interval and J wave before and after PCI,and to analyze their relationship with ACS types and disease degree and their predictive value on poor prognosis such as MVA and SCD in patients,so as to provide reference for future cardiac function changes and prognosis evaluation after PCI.MethodsAll cases data were from ACS patients(case group)who underwent PCI in our hospital from January 2017 to June 2018,108 cases in total.According to ACS types,they were divided into UAP group(UAP cases,42cases),NSTEMI group(NSTEMI cases,36 cases)and STEMI group(STEMI cases,30 cases).Gensini score was used to evaluate the degree of coronary artery disease,and patients were divided into mild group(Gensini score≤ 20 points,37 cases),moderate group(20 points<Gensini score ≤ 40 points,44 cases)and severe group(Gensini score >40 points,27 cases).Another 40 patients with non-coronary heart disease(CHD)who had similar or close baseline data with case group were selected as controls(control group).The general data at admission were collected among all patients,and the follow-up was maintained for at least 6 months,and patients were further grouped according to whether MVA occurred during follow-up in case group,including MVA group(27 cases with MVA)and nMVA group(81 cases patients without MVA).Depending on whether SCD occurred during follow-up,the patients were divided into death group(9 cases with SCD)and survival group(survival,99 cases).The QTd,HRV parameters[interval standard deviation(SDNN),mean normal R-R interval standard deviation(SDANN)and continuous normal R-R interval root mean square of difference(rMSSD)of continuous 5min segment within 24 h,percentage of heartbeats frequency with two adjacent R-R interval standard deviation≥ 50 ms in heartbeats frequency during information analysis interval(PNN50)] Tp-Te interval and J wave were compared and analyzed before and after PCI in each group and subgroup,and SPSS 19.0 statistics software was used for analysis.Results1.There were no significant differences in the blood lipids indexes and serum creatinine in case group before PCI compared with those after PCI(P>0.05),and the cardiac troponin I(cTnI),creatine kinase isoenzyme(CK-MB)and their peak values after PCI was significantly decreasedcompared with those before PCI(P<0.05),but were still higher than those in control group(P<0.05).2.The QTd and Tp-Te interval in case group after PCI were significantly shortened compared with those before PCI(P<0.05),but were still longer than those in control group(P<0.05).The SDNN,SDANN,rMSSD and PNN50 were significantly increased compared with those before PCI(P<0.05),but were still significantly lower than those in control group(P<0.05).There were no ischemic J waves in control group.134 ischemic J waves appeared in case group before PCI,and were decreased to 78 after PCI,and the decrease rate was 41.79%,and there was a statistical difference in the distribution of ischemic J wave grading before and after PCI(P<0.05).Correlation analysis showed that the QTd and Tp-Te interval of ACS patients after PCI were positively correlated with peak values of cTnI and CK-MB(P<0.05),and HRV parameters(SDNN,SDANN,rMSSD,PNN50)were positively negatively correlated with peak values of cTnI and CK-MB(P<0.05).Ischemic J wave grading of ACS patients after PCI was positively correlated with peak values of cTnI and CK-MB(P<0.05).3.Comparison of QTd and Tp-Te interval after PCI in patients with different types of ACS and different degrees of coronary artery disease showed UAP group <NSTEMI group<STEMI group,and mild group<moderate group<severe group(P<0.05).Comparison of SDNN,SDANN,rMSSD and PNN50 showed UAP group>NSTEMI group>STEMI group,and mild group>moderate group>severe group(P<0.05).There were 78 ischemic J waves after PCI,and there were statistical differences in the ischemic J wave grading distribution among UAP group,NSTEMI group and STEMI group and ischemic J wave grading distribution among mild group,moderate group and severe group(P<0.05).Correlation analysis showed that QTd and Tp-Te interval of ACS patients after PCI were positively correlated with Gensini scorebefore PCI(P<0.05),and HRV parameters(SDNN,SDANN,rMSSD,PNN50)were negatively correlated with Gensini score before PCI(P<0.05).Ischemic J wave grading after PCI was positively correlated with Gensini score before PCI(P<0.05).4.Compared with nMVA group,the QTd and Tp-Te interval after PCI were significantly longer in MVA group,and the SDNN,SDANN,rMSSD and PNN50 were significantly lower(P<0.05).Compared with survival group,the QTd and Tp-Te interval after PCI were significantly longer in death group,and the SDNN,SDANN,rMSSD and PNN50 were significantly lower(P<0.05).There were significant differences in the ischemic J wave grading distribution between nMVA group and MVA group and ischemic J wave grading distribution between survival group and death group(P<0.05).5.Logistic regression analysis showed that eTnI peak value and CK-MB peak value before and after PCI,and QTd,HRV,Tp-Te interval and ischemic J wave grading after PCI can be used as predictors of MVA and SCD during follow-up after PCI(P<0.05).Conclusions:1.PCI can effectively improve cardiac function of patients with ACS,promote improvements of QTd,HRV,Tp-Te interval and J wave.2.Improvement effects of QTd,HRV,Tp-Te interval and J wave after PCI are closely related to myocardial injury(peak values of cTnI and CK-MB),and are also closely related to ACS types and degree of coronary artery disease.3.QTd,HRV,Tp-Te interval and ischemic J wave grading detection after PCI can be used as predictors of MVA and SCD. |
