Value of T-wave direction with lead III ST-segment depression in acute anterior wall myocardial infarction: Electrocardiographic prediction of a 'wrapped' left anterior descending artery

Background: Lead III ST-segment depression during acute anterior wall myocardial infarction (AMI) has been attributed to reciprocal changes. However, the value of the T- wave direction (positive or negative) in predicting the site of obstruction and type of the left anterior descending (LAD) artery is not clear and has not been studied before. Hypothesis: The aim of the study was to assess retrospectively the correlation between two patterns of lead III ST-segment depression, and type of LAD artery and its level of obstruction during first AMI. Methods: The study group consisted of 48 consecutive patients, admitted to the coronary care unit for first AMI, who showed ST-segment elevation in lead aVL and ST-segment depression in lead III on admission 12-lead electrocardiogram. The patients were divided by T- wave direction into Group 1 (n = 31), negative T wave, and Group 2 (n = 17), positive T wave. The coronary angiogram was evaluated for type of LAD ('wrapped', i.e., surrounding the apex or not), site of obstruction (pre- or postdiagonal branch), and other significant coronary artery obstructions. Results: Mean lead III ST-segment depression was 1.99 ± 1.32 mm in Group 1 and 1.13 ± 0.74 mm in Group 2 (p = 0.004); mean ST-segment elevation in aVL was 1.35 ± 0.84 mm and 1.23 ± 0.5 mm, respectively (p = 0.5). A wrapped LAD was found in 12 patients (38.7%) in Group 1 and in 13 in Group 2 (76.4%) (p = 0.02). The sensitivity of lead III ST-segment depression with positive T wave to predict a wrapped LAD was 52%, and the specificity was 82% with a positive predictive value of 76%. On angiography, 25 patients (80%) in Group 1 and 13 (76%) in Group 2 had prediagonal occlusion of the LAD (p = 0.77). No significant difference between groups was found for right and circumflex coronary artery involvement or incidence of multivessel disease. Conclusions: The presence of lead III ST-segment depression with positive T wave associated with ST-segment elevation in aVL in the early course of AMI can serve as an early electrocardiographic marker of prediagonal occlusion of a 'wrapped' LAD.