Twelve lead electrocardiagram is often used to localize the site of myocardial infarction and coronary artery stenosis. There are many studies to correlate the electrocardiographic abnormalities and the site of coronary artery stenosis in patients with ischemic heart disease. In patients with acute myocardial infarction, however, a few studies that correlate the site of coronary artery stenosis and abnormal Q wave in leads I or aVL have been reported.

In 60 patients with acute myocardial infarction(Male : Female=48 : 12), the author investigated the development of abnormal Q wave in leads I or aVL and the presence, severity and location of stenosis in left anterior descending coronary artery and its first diagonal branch, and correlated abnormal Q wave and the presence of first diagonal branch stenosis with the progression of myocardial infarction.

The presence of first diagonal branch stenosis can be predicted in patients with acute myocardial infarction who had abnormal Q wave in leads I of aVL with sensitivity and specificity of 70% and 85% during the early stage respectively and 88% and 96% after stabilization of infarction respectively.

With the presence of abnormal Q wave in leads I or aVL in patients with acute myocardial infarction, it can be predicted that there is stenosis in the first diagonal branch. Howeve, there should be more experineces and further and metriculous studies.