Mechanism And Value Of The Electrocardiogram In Predicting The Site Of Lesion In The Left Anterior Descending Artery In Acute Myocardial Infarction

To investigate mechanism and value of the electrocardiogram(ECG) as predictor of the left anterior descending coronary artery (LAD) occlusion site in patients with acute anterior myocardial infarction(AAMI), and to analysis the characters of ECG and coronary artery configuration in patients with acute anteroseptal myocardial. Methods and results Between 1999 and 2004, 58 patients (51 men, 7 women) with anterior wall AMI were admitted to our coronary care unit in TIAN JIN medical university general hospital. The study was divided into two parts: in the first part the relation of the LAD occlusion and changes in ECG was investigated in patients with anterior wall AMI; in the second part the characters of the LAD occlusion site and coronary artery were analyzed in patients with acute anteroseptal wall myocardial infarction.The first part: The patients were divided into two pairs groups, proximal to S1 group, distal to S1 group, proximal to D1 group and distal to D1 group,according to the culprit site in relation to the first septal perforator (SI) and the first diagonal branch (Dl) as documented by coronary angiography, and analyzed retrospectively 12-lead ECG upon admission to the CCU. The second part: the patients were divided into anterior wall group and anteroseptal wall group according to ECG diagnosis and analyzed retrospectively coronary angiography result in order to find out the characters of LAD occlusion and coronary artery configuration.The data were analyzed using SPSS 11.0 for Window. Probability value < 0.05 was considered statistically significant. Results The first part: 1. (1) ST-segment depression >0.05mV in leads n , III and aVF was present in 62.5%, 53.1 %, 56.3% and in 11.1% (p=0.000) ,38.9% (NS) ,33.3% (P=0.024) of the occlusion distal to SI, respectively. ST-segment depression in lead II is most highly predictive of LAD occlusion proximal to SI in inferior leads. (2) The amount of ST-segment elevation in aVR lead was 0.040.10mV in proximal to SI group, whereas the amount of ST-segment elevation was -0.03?.06mV (p=0.002). (3) ST-segment elevation0.25mV in VI lead was only present in LAD occlusion proximal to SI, but the sensitivity of this criterion was very low, only 32.3%. ST-segment depression in V5 and/or V6 leads was mostlypresent in LAD occlusion proximal to SI. (4) CRBBB was registered in 8 patients which LAD occlusions were all proximal to S1. (5) QRS axis shifted to left more significantly in LAD occlusion proximal to SI than distal to SI (p=0.03) 2. ST-segment elevation in I lead was observed in 53.8% of patients with LAD occlusion proximal to Dl and in 17.4% of patients with LAD occlusion distal to Dl (p=0.016). ST-segment elevation in aVL lead was present in 73.1% of patients with LAD occlusion proximal to Dl and in 38.4% of patients with LAD occlusion distal to Dl (p=0.007). The second part: 1. The amount of ST-segment elevation in lead I was -0.14?.44 and 0.44?.09mV (pK).009) in anterior wall group and anteroseptal wall group respectively. ST-segment elevation0.05mV in lead I was only present in anterior wall group (p=0.006). The amount of ST-segment elevation in aVL lead was 0.00?.04 and 0.06?.10mV (p=0.001) in both two groups respectively. ST-segment elevation 0.05mV in lead aVL was present 15(45.5%) patients in anterior wall group, whereas was present 1(6.3%) patient in anteroseptal wall group(p=0.001). 2. Lesion site of LAD in all 16 patients(100%) with anteroseptal wall AMI group was proximal to the first septal branch (SI), which the incidence was higher than 15 patients (45.5%) inanterior wall AMI group (p=0.000). The incidence of patients with mtermedius branches or high obtuse marginal branch in anteroseptal AMI group (75%) more than in AAMI group (39.4%, p=0.019). Conclusion 1. In AAMI due to 1-vessel LAD occlusion, ST-segment depression in inferior leads and lead V5 and V6, ST-segment elevation in lead aVR, ST-segment elevation 0.25mV in lead VI, CRBBB and QRS axis shift left predict a culprit lesion in the LAD proximal to SI. 2. In AAMI, ST-segment elevat...