Electrocardiographic criteria for predicting site of coronary artery occlusion in acute inferior wall myocardial infarction

Abstract EN

Background The determination of infarct related artery in acute inferior myocardial infarction is extremely important for the prediction of potential complication and predicting the probable site of occlusion is worthwhile because proximal occlusions are likely to cause greater myocardial damage and early invasive strategy is indicated.

Objectives:To predict the culprit coronary artery whether right coronary artery or left circumflex artery by examining the surface electrocardiography in patients with acute inferior wall myocardial infarction and also to predict the correlation between the proximity of lesion in right coronary artery and severity of ST segment elevation in inferior electrocardiographic leads that is caused by right coronary artery occlusion .

Methods : A total of 56 patients with inferior wall myocardial infarction were included in this study underwent coronary angiography.

the electrocardiography of these patients were then compared with angiographic finding to correlate with culprit artery (either right coronary artery or left circumflex) and also to correlate the proximity of culprit lesion in right coronary artery with the degree of ST segment elevation in inferior limb leads.

Results: After comparing the electrocardiographic findings in inferior and lateral leads ,it was evident that the degree of ST segment elevation in leads III and AVF was significantly higher in right coronary artery group (46 patients) vs left circumflex group (10 patients) 3.16 ± 1.14mm vs 1.53 ± 0.24mm (p < 0.001) and 2.78 ± 0.92mm vs 1.2 ± 0.25 (p < 0.001) respectively.

While its comparable in lead II 2.18 ± 0.95mm vs 1.7 ± 0.34mm (p > 0.05).In respect to lateral limb leads (AVL and I), we found that deeper ST segment depression was in right coronary artery group as compared to left circumflex group 1.11 ± 0.25mm vs 0.2 ± 0.34mm (p < 0.001) and 0.69 ± 0.25mm vs 0.25 ± 0.42mm (p < 0.001).

In precordial leads V2 and V3 we found that the left circumflex group had deeper ST segment depression compared to RCA group although the difference was of no statistical significance 1.9 ± 0.56mm vs 1.55 ± 0.76mm (p > 0.05)and 2.1 ± 0.56 mm vs 1.73 ± 0.71mm (p > 0.05) respectively.

Also in right coronary artery group, 15 (32.6 %) patients had proximal culprit lesion, 19(41.6 %) mid and 12 (26 %) distal culprit lesion.

Patient with proximal right coronary artery disease showed a mean ST segment elevation of 11.7 ± 1.8mm and with mid right coronary artery disease 7.2 ± 0.97mm and with distal right coronary artery disease 5.8 ± 0.82mm.

Conclusion 1-It is possible to predict the culprit artery whether right coronary artery or left circumflex by examining the surface electrocardiography in patients with acute inferior myocardial infarction.

2-The degree of ST segment elevation is correlated with proximity of the right coronary artery.