Discussion Of The Relationship Between ST Segment Changes In ECG And The Result Of Coronary Angiography In Non-ST-Segment Elevation Myocardial Infarction

Background and purpose:With the continuous improvement of diagnostic techniques, the proportion ofNSTEAMI in acute coronary syndrome has gradually increased, which has become the hotand difficult point of cardiovascular disease.Comparing the changes of the chest lead STsegment depression in the surface ECG and the results of coronary angiography in thisstudy,we are to explore the relationship between them and the value of ECG in predictingthe coronary vascular disease in non-ST-segment elevation myocardial infarction. We hopethis research will provide clinicians with a reference to predict the diseaseand takeintervention measures.Methods:46patients(22males and24females) who were diagnosed with non-ST elevationmyocardial infarction from January1,2008to February28,2012in our hospital were allenrolled in this study. All the cases were ranged from38to87years old, with the average(63.43±12.37) years old. Hypertension existed in22cases (48%), diabetes existed8cases(17%). all the standard12-lead ECG test were given when the patient were at onset andthe Coronary angiography were done within24hours or6-7days. Based on the changes ofPrecordial st-segment electrocardiogram and the inclusion and exclusion criteria, all46patients were divided into two groups: the precordial ST segment depression group(38cases), precordial ST-segment without depression is another group(8cases). All the patientsunderwent standard12-lead body surface ECG and coronary angiography, the patient’sgeneral condition,including gender, age, medical history, blood pressure, heart rate, bloodlipids, blood glucose, serum creatine kinase, troponin I were also recorded. the changes ofECG and the results of the coronary angiography of patients at the onset, the incidence ofpreoperative, postoperative were also recorded. All the Measurement data in this study areexpressed in the mean±standard deviation (x±s), the measurement data of the two groupsof were compared using independent samples t test. Enumeration data were compared usingchi-square test, the exact probabilities are used when the theoretical frequency is less than1 or the total number of samples is less than40. The correlation are tested using Pearsonlinear correlation and Logisti regression analysis. All statistics were two-sided test, a P valueof less than0.05(2-tailed) was statistically significant. SPSS17.O software was used forstatic analysis.Result:In this study, the average age of precordial ST-segment depression group is(63.8±11.8)years old while the average of precordial ST-segment without depression was (61.6±15.3)years old. The age of two groups were compared using independent samples t test(p>0.05),which shows that the difference of age between the two groups were not statisticallysignificant.46patients of non-ST-segment elevation myocardial infarction were studied inthis study, with a total of138vascular lesions examined.the distribution of the relatedvessels includes60in the proximal lesion,53in the middle of the lesion,25in the distallesion. Tthere are23cases of which the area of stenosis segment is less than50%,24casesof which is greater than or equal to50%and less than74%,29cases of which is greater thanor equal to75%and less than90%,62cases of which is greater than or equal to90%. Ofthe selected cases,the location of the5cases existed in left main branch.four cases exist inprecordial ST segment depression group while the other case exists in the precordial ST-segment without depression. The18cases of triple vessel disease, double vessel diseasein13cases,10cases of single vessel disease, and single and double vessel disease,multi-branch vessels and vessel stenosis less than50%. Formation of collateral circulationfor a total of five cases.According to the location of the stenosis segment of the bloodvessels,there are49cases in the proximal lesion,43cases in middle of the lesion,24casesin the distal lesion in the precordial ST-segment depression group. At the same time,thereare11cases,10cases and1cases respectively in Group of precordial ST-segment withoutdepression. Comparing the two groups based on the location of the stenosis segment usingchi-square test,the P values of the proximal lesion,the middle of the lesion,and the distallesion is0.661,0.615,0.133respectively,making no statistically difference between the twogroups. As to th area of stenosis segment,there are17cases of which the related area is lessthan50%,20cases is greater than or equal to50%and less than74%,22cases is greater thanor equal to75%less than90%,57cases is greater than or equal to90%in the group ofprecordial ST segment depression,while the number of the three rows in group of precordialST-segment without depression is6,4,7,5. Comparing the two groups based on the area ofthe stenosis segment using chi-square test, the P values in the two groups is 0.253,1.000,0.284,0.040respectively,with only0.040less than0.05.It shows that thestatistically significance only exists when the area of stenosis segment is more than90%between the two groups. We also find that ECG changes is more likely to happen when thearea of coronary stenosis is greater than or equal to90%in this study(P <0.05).Thedistribution of coronary artery involved in the group of precordial ST segment depression:include four cases in left anterior descending artery lesions, one case in the circumflex arterylesions, three cases in the right coronary artery, four cases in both left anterior descendingartery and circumflex artery lesion, four cases in both descending artery and right coronarylesions, three case in both the circumflex arterys and right coronary artery lesions.15cases exist triple vessel disease, accounting for39.5%, of whichfour cases is in of left mainbaranch;while in the the group of precordial ST segment without depression,the number is2,0,0,1,1,0.and there are1cases exist triple vessel disease.Comparing the two groups basedon the distribution of coronary artery disease using chi-square test,,the P values is more than0.05,making no statistically difference between the two groups. But the proportion of caseswith triple main vessel involved in the two groups is39.5%and37.5%.The number ofcoronary artery lesions involved in the in the chest lead ST segment depression group: singlelesion exists in8cases, double vessels involved exists in11cases,and multiply-vessel lesion(greater than or equal to3vascular disease) exists in9cases; while in the group ofprecordial ST segment without suppression,the number is two, two,and4. Comparing thetwo groups based on The number of coronary artery lesions involved using Chi-square testrespectively, the P values were greater than0.05between the two groups in single, double,multiply-vessel disease, making no significant difference. But the proportion of cases with isboth50.0%.Conclusions:Precordial ST segment depression can prompt that a coronary artery with severestenosis. Precordial ST segment depression can not determine the number of the coronarystenosis arteries, the location of stenosis and the stenosis.