Clinical And Electrocardiographic Characteristics Of Acute Myocardial Infarction With Left Circumflex Artery As Criminal Vessel

Background: The international/domestic morbidity and mortality of acute myocardial infarction are on the rise.Electrocardiograph(ECG)is very important for the diagnosis of acute myocardial infarction,especially acute ST-segment elevation myocardial infarction,but for acute non-ST-segment elevation myocardial infarction,the sensitivity and specificity of ECG are significantly reduced.Some patients with vascular occlusion but no ST-segment elevation in ECG were identified as acute non-ST-segment elevation myocardial infarction,which could not be timely revascularized,meanwhile the prognosis of these patients was similar to even worse than that of patients with acute ST-segment elevation myocardial infarction.Among them,ECG manifestations of acute myocardial infarction with left circumflex artery as criminal vessel are various,especially non-ST-segment elevation myocardial infarction,which has no typical ECG manifestations,leading to delayed identification of left circumflex artery as criminal vessel,delayed emergency revascularization,thus affecting the prognosis of patients and even endangering the lives of patients.Objective: To summarize the clinical and electrocardiographic characteristics of acute myocardial infarction(AMI)with left circumflex as criminal vessel,analyze the factors that may cause occlusion of left circumflex artery without ST-segment elevation in ECG,select more characteristic ECG features of patients with non-ST-segment elevation,and identify the acute non-ST-segment elevation myocardial infarction with left circumflex artery as criminal vessel as early as possible.Methods: After screening by inclusion criteria and exclusion criteria,there are a total of 227 patients with acute myocardial infarction admitted to the First Affiliated Hospital of Chongqing Medical University were selected.All patients underwent coronary angiography to confirm that the left circumflex artery was the culprit vessel.The clinical data and the results of ECG,color Doppler echocardiography and coronary angiography were analyzed.All patients with acute myocardial infarction were divided into ST-segment elevation group(STEMI group)and non-ST-segment elevation group(NSTEM group)according to whether ST-segment elevation was present or not.The characteristics of the two groups were compared;the ECG manifestations of NSTEMI group were summarized;and the possible factors causing left circumflex branch occlusion but not elevation of ST-segment of ECG were analyzed.Result: For patients with acute myocardial infarction,NSTEMI group had more history of angina pectoris before onset(P < 0.001),the FMC and the time of operation distance were significantly longer than the STEMI group(P = 0.002),and the level of troponin was lower than that of STEMI group(P = 0.007).Left ventricular ejection fraction in NSTEMI group was lower than that in STEMI group,though there was no significant difference between two groups(P=0.083);there was no significant difference in prognosis between STEMI group and NSTEMI group(P>0.05).The occurrence rate of "V1 lead T wave upright and V4-V6 lead ST segment depression" in NSTEMI patients was significantly higher than that in other ECG manifestations.Possible causes of left circumflex branch occlusion but no elevation of ST segment in ECG: angina pectoris and LCX with RCA.Conclusion : The STEMI group had earlier diagnosis and higher troponin level;angina pectoris before onset was more common in NSTEMI group;the possible factors causing left circumflex branch occlusion but not ST segment elevation were as follows: angina pectoris attack before onset,collateral circulation formation,lack of record of V7-V9 lead in12-lead ECG,left circumflex anatomical characteristics,occlusion lesion location,combined with multiple vessel lesions;The electrogram showed that the T-wave of lead V1 was upright and ST-segment depression of lead V4-V6 had statistical significance in the diagnosis of left circumflex branch ascriminal vessel.