Diagnostic value of electrocardiogram in acute myocardial infarction associated with different circumflex branches

Abstract

Objective To investigate the characteristics of body surface electrocardiogram (ECG) of different segments of circumflex artey (LCX) occlusion. Methods The ECG characteristics of 85 patients with acute myocardial infarction caused by LCX occlusion in the People's Hospital of Rugao, Jiangsu, from February 2015 to February 2018 were analyzed.The results of coronary angiography were taken as the criteria.The efficacy of the body surface ECG for the diagnosis of LXC occlusion of acute myocardial infarction was analyzed by receiver operating characteristic curve (ROC). Results The ECG of right dominant LCX occlusion was dominated by STⅡ, Ⅲ, AVF elevation (76.47%), and the balance type was dominated by STV1-V3 (68%), and the dominant left dominant type was STⅡ, Ⅲ, AVF elevation (88.89%) and STV7-V9 elevation (66.67%). STV1-V3 moved down, STⅡ, Ⅲ, AVF elevation, STV7-V9 elevated in different coronary points.The differences between the two groups was statistically significant (χ2=4.028, 4.061, all P<0.05). The ECG changes of LCX occluded in the distal and middle segments were dominated by STⅡ, Ⅲ, AVF (100%, 78.95%), and the proximal and blunt branches were dominated by STV1-V3 (88.24%). STV1-V3 moved down, STⅡ, Ⅲ, AVF elevation, STⅠ, aVL elevation and STV7-V9 elevation had statistically significant differences(χ2=6.024, 5.318, 4.971, all P<0.05). The sensitivity, specificity, positive predictive value, negative predictive value, accuracy, and area under the curve of STV1-V3, STⅡ, Ⅲ, AVF elevation were 82.06%, 92.63%, 89.91%, 86.34%, 88.06%, 0.830 (95%CI: 0.853-0.991), respectively, and 86.83%, 95.37%, 92.38%, 88.61%, 90.64%, 0.922 (95%CI: 0.729-0.931), respectively, the efficiency is better than STⅠ, aVL and STV7-V9. Conclusion The body surface ECG of LCX occlusive acute myocardial infarction is varied with various factors.STV1-V3 shift, STⅡ, Ⅲ, AVF elevation are of high diagnostic value for LCX occlusion of acute myocardial infarction, and the clinical history and other methods should be used for accurate diagnosis. Key words: Myocardial infarction; Coronary occlusion; Electrocardiography; Circumflex artery