Analysis Of Influencing Factors Of QT Interval Change After Successful Reperfusion Therapy In Patients With Acute Myocardial Infarction And Its Correlation With Clinical Prognosis

Objective To analyze the influencing factors of QT interval change in patients with acute myocardial infarction after successful reperfusion therapy and explore its correlation with clinical prognosis.Methods In retrospective study,383 patients with AMI received percutaneous coronary intervention(PCI)at Zhongshan Hospital Affiliated to Dalian University from January 2015 to January 2022,and were followed up one year later.By collecting patients’ medical history,various physical and chemical examination indexes,coronary artery lesions,preoperative myocardial infarction area blood perfusion status,coronary intervention operation and use during operation,postoperative cardiac blood perfusion status and cardiac function status during hospital,Corrected QT interval(QTc)and QTc dispersion(QTcd)were measured in the patients’ emergency,1 hour after surgery,and 1,2,and 3 days after surgery.To observe the change characteristics of QTc and QTcd after PCI,analyze the relevant influencing factors of QTc and QTcd after PCI,and analyze the correlation between the changes of QTc and QTcd after PCI and adverse clinical events during hospitalization and one year after discharge.Result 1.During hospitalization,ECG QTc changes showed a parabolic trend and reached a peak on the second day after PCI.Among the 203 patients(53%),at least one ECG showed prolonged QTc after surgery.The patients were divided into QTc prolongation group(n=203)and normal group(n=180).The age of patients in the prolonged group was(65.20±12.45)years vs.(61.96±13.40)years.P=0.014)] and the proportion of preoperative prolonged QTc(30.0% vs.9.4%,P < 0.001)was higher than that of non-prolonged group,the proportion of hyperuricemia(36.5% vs.49.4%,P= 0.001),the proportion of intraoperative tirofiban(14.3% vs.28.3%,P = 0.001)and thrombus extraction rate(21.2% vs.33.9%,P = 0.001)were lower than those in the non-prolonged group.The incidence of prolonged QTc was significantly higher in patients with anterior wall myocardial infarction than in patients without anterior wall myocardial infarction(65.7% vs.47.5%,P=0.015)and non-ST-elevation myocardial infarction(NSTEMI)(65.7% vs.42.9%%,P=0.005).2.QTcd was significantly prolonged after PCI,and then showed a downward trend.Angina pectoris before infarction was negatively correlated with the maximum QTcd after PCI(r=-0.152,P=0.003).Hyperuricemia(r=0.144,P=0.005),intraoperative tirofiban(r=0.114,P=0.026)and thrombus aspiration were positively correlated with the maximum value of QTcd after PCI(r=0.109,P=0.033).Multivariate analysis showed that angina pectoris before infarction was independently correlated with the maximum value of QTcd after PCI(OR:-2.556,95%CI:-4.784~-0.327,P=0.025).3.There were 103 patients(26.9%)with heart failure during hospitalization,and there was no significant difference in the incidence of postoperative QTc prolongation between patients with heart failure(n=103)and those without heart failure(n=280)(60.2% vs.50.4%,P=0.087),the maximum value of postoperative QTcd was significantly higher than that of patients without heart failure [(81.29±10.99)ms vs.(79.91±11.08)ms,P < 0.001].Univariate correlation analysis showed that there was no significant correlation between the maximum value of postoperative QTc and the complication of heart failure during hospitalization(r=0.087,P=0.088),and the maximum value of postoperative QTcd was positively correlated with the complication of heart failure during hospitalization(r=0.263,P < 0.001).146 patients(38%)had decreased LVEF on ultrasound during hospitalization,and the incidence of postoperative prolonged QTc in patients with decreased LVEF(n=146)was 62.3 vs.47.3%,P=0.04)and the maximum value of postoperative QTcd [(83.55±9.11)ms vs.(79.90±11.81)ms,P=0.002] were higher than those of patients with normal LVEF(n=237).Univariate correlation analysis showed that the maximum value of postoperative QTc(r=0.203,P < 0.001)and the maximum value of postoperative QTcd(r=0.155,P=0.002)were positively correlated with the decrease of LVEF.Ten patients(2.6%)died of cardiogenic death during hospitalization.The incidence of prolonged QTc(40% vs.53.4%,P=0.404)and the maximum postoperative QTcd((85.21±12.49)ms vs.(81.18±10.95)ms,P= 0.253)in patients who died(n=10)were not significantly different from those who survived(n=373).4.373 patients who survived during hospitalization were followed up 1 year later,and 41(11.0%)patients had major adverse cardiac events(MACE).The incidence of postoperative QTc prolongation was greater than that in the group without MACE event(n=363)(80.5% vs.50.0%,P < 0.001),and there was no significant difference between the maximum postoperative QTcd and the group without MACE event[(80.91±10.27)ms vs.(81.22±11.05)ms.P=0.865].The K-M survival curve revealed that those with prolonged QTc had a less event-free survival rate than those with non-prolonged QTc.QTc(P < 0.001).Receiver operating characteristic(ROC)curve shows: The area under the curve of postoperative QTc to predict MACE events in AMI patients within 1 year after PCI was 0.690.The optimal critical value of postoperative QTc to predict the maximum sensitivity and specificity of MACE occurrence was 465.5ms(sensitivity 73.2%,specificity 62.6%).73.2%(30/41)of MACE events occurred in patients with QTc > 465.5ms.Conclusion1.The prolongation of postoperative QTc in AMI patients who successfully underwent direct PCI is associated with decreased cardiac function during hospitalization;Patients with a 1-year event-free survival rate lower than those with normal QTc after discharge.2.The postoperative QTcd of AMI patients who successfully underwent direct PCI is positively correlated with decreased cardiac function and heart failure during hospitalization.