Changes And Clinical Significance Of Electrocardiographic Repolarization After Revascularization Of Chronic Total Occlusion Of Coronary Artery

Objective In recent years,the clinical research of chronic total occlusion(CTO)disease of coronary arteries has attracted more and more attention from experts and scholars,and has become a research focus in recent years.These clinical studies suggest that the clinical symptoms of patients with CTO can be improved after percutaneous coronary intervention of occluded vessels.The improvement depends on the enhancement of myocardial activity and the reduction of ventricular arrhythmia.These two changes are often related to the changes of ECG repolarization indexes.Repolarization is a process in which cardiomyocytes return to resting potential level after depolarization.T-wave amplitude,QT rate-correct interval(QTc),Tpeak-Tend(Tp-Te)and other repolarization indexes were correlated with myocardial activity,quantity of viable myocardium and malignant arrhythmia.The improvement of myocardial repolarization indexs can significantly improve myocardial viability,reduce the heterogeneity,asynchrony and instability of its electrical activity,so as to improve the function of myocardial cells,and finally improve the clinical symptoms of patients.However,there are few studies on the changes of ECG indexes of patients with CTO after the interventional operation.This study will compare the characteristics of ECG repolarization indexs in patients with CTO,as well as changes in T-wave amplitude,Tp-Te and other ECG indexs after revascularization.Methods From May 2017 to May 2019,249 patients who underwent CTO percutaneous coronary intervention in cardiovascular department of our hospital were enrolled.According to the number of occluded vessels,they were divided into single-vessel CTO group(192 cases)and multi-vessel CTO group(57 cases).The changes of T wave amplitude,QTc and Tp-Te of repolarization indexs after CTO-PCI were compared between the two groups.Depending on whether there is an old myocardial infarction,single-vessel CTO group was divided into two subgroups: CTO group with old myocardial infarction(MI CTO group,106 cases)and CTO group without old myocardial infarction(non MI CTO group,86 cases).The twelve-lead ECG repolarization indexs was compared between the two subgroups,and the changes in repolarization indexs before and after revascularization were compared within the group.The single-vessel CTO group was divided into left anterior descending branch group(LAD group,82 cases),right coronary artery group(RCA group,91 cases)andleft circumflex branch group(LCX group,19 cases)according to occluded vessel.The repolarization indexes before and after operation were compared.All patients were followed up for six months to compare the improvement of NYHA grading and the occurrence of major adverse cardiac events(MACE).Results(1)Among the indicators of ECG repolarization in the two groups,patients with multi-vessel CTO groups had more T-wave amplitude improvement after surgery than those with single-vessel CTO group(c2= 27.566,p = 0.000)and QTc(t = 3.622,P =0.000)were smaller,The difference between the two groups is statistically significant(p<0.05).The postoperative Tp-Te index of the two groups is significantly different than that before surgery(p<0.05).(2)Patients in the two groups were followed up for six months.NYHA grading multi-vessel CTO group(c 2 = 26.687,p = 0.000),and single-vessel CTO group(c 2 = 16.223,p = 0.001)were improved compared with preoperative,the difference was statistically significant(p <0.05),However,the incidence of MACE was lower in the multi-vessel CTO group(8.772%,c 2=4.024,p=0.045),which was statistically significant compared with the single-vessel CTO group(p < 0.05).(3)Subgroup analysis of single-vessel CTO showed that there were statistically significant differences between the two subgroups in the T-wave amplitude of preoperative lead III,AVF and the Tp-Te index of lead AVF,V4,V6(P < 0.05).(4)Compared with the preoperative results,the ecg repolarization index of the MI CTO group after revascularization showed statistically significant differences in lead III T-wave amplitude,AVL lead and V3 lead Tp-Te(P < 0.05).In the non-MI CTO group,after revascultation,there was no statistically significant difference in T-wave amplitude of all lead leads compared to the preoperative group,and there were statistically significant differences between I lead,III lead,AVR lead,AVF lead,V4 lead,V5 lead,and V6 lead Tp-Te compared with the preoperative group(P < 0.05).(5)The QTc of LCX group was smaller than that of LAD group and RCA group(P < 0.05),but there was no significant difference in preoperative Tp-Te,postoperative QTc and Tp-Te among the three groups(P > 0.05).Conclusion(1)The repolarization indexes of multi-vessel CTO patients improved significantly after revascularization,with greater clinical benefit,while only Tp-Te improved significantly in single-vessel CTO patients.(2)Patients without old myocardial infarction in single-vessel CTO have higher T-wave amplitudes and greater dispersion of repolarization than patients with old myocardial infarction.The repolarization dispersion index is more significantly improved after revascularization.(3)In patients with single-vessel CTO,LCX occlusion has little effect on repolarization index.