Importance of reciprocal leads in acute myocardial infarction.

OBJECTIVES: To study the relevance of the ECG changes in the reciprocal leads in patients with acute anterior and inferior wall myocardial infarction, with regard to culprit artery localization and left ventricular (LV) function.

METHODS: Three hundred patients of acute myocardial infarction (AMI) (180 anterior, 120 inferior) aged between 30-90 years (mean age - 60 yrs; M:F - 220:80) were studied with regard to the reciprocal lead changes which were correlated with the culprit coronary artery and LV function. 285/300 (95%) patients underwent echocardiography and 62/300 (20.67%) underwent coronary angiography (CAG).

RESULTS: In patients with acute anterior wall MI (AWMI), Q wave in inferior leads was found in 38.8% (70/180) patients. Nineteen patients underwent (CAG) and all 70 patients underwent 2D echocardiography. CAG revealed 10/19 and 9/19 patients to have single vessel disease (SVD) and multivessel disease (MVD), respectively. In presence of SVD, 80% (8/10) patients were found to have a distal/mid LAD occlusion. The echocardiogrpahy of these 19 patients showed that 15/19 (78.94%) of these had LV ejection fraction (EF) > 40% as against only 4/19 (21.05%) patients with LVEF < 40%. The echocardiographic study of patients with and without reciprocal ST depression in inferior leads more than or equal to the ST elevation in anterior leads, showed higher incidence of LV dysfunction i.e. LVEF < 40% in patients with reciprocal changes (72.05%) as compared to patients without the reciprocal changes (27.94%). In patients with acute inferior wall MI (IWMI), anterior and lateral ST depression more than or equal to ST elevation in inferior leads was found in 80% (96/120) patients. 27/96 patients underwent coronary angiography and all 96 underwent echocardiography. Patients with ST depression in I, a VL, V4-V6 (apicolateral leads) > or = ST elevation in inferior leads were found to have more occurrence of multivessel disease (21/27) with LVEF < 40% (50/64 i.e. 78.12%, P < 0.001). 12.5% (4/32) patients with reciprocal changes in anterior i.e. VI-V3 leads and 15% (3/20) patients without significant reciprocal changes in anterior and lateral leads had LVEF < 40%. Also, patients with ST depression in I, aVL showed higher incidence of right coronary artery (RCA) lesion (23/27) (P < 0.001).

CONCLUSIONS: Patients of acute AWMI with Q waves in inferior leads indicate a smaller infarct with higher incidence of mid/distal LAD occlusion and a relatively preserved LV function. AWMI patients without reciprocal changes in inferior leads have a better LVEF. Patients of acute IWMI with ST depression in apicolateral leads have more occurrence of multivessel disease with significant LV dysfunction. Reciprocal ST depression in I, aVL suggests a possibility of RCA lesion.