The angiographic correlation between ST segment depression in noninfarcted leads and the extent of coronary artery disease in patients with acute inferior myocardial infarction: a clue for multivessel disease

BACKGROUND: Although reciprocal ST segment depression (RSTD) in patients with acute inferior myocardial infarction is a common electrocardiogram finding, its significance is not yet established. In this prospective study, the relationship between RSTD and the extent of coronary artery disease (CAD) was investigated. PATIENTS AND METHODS: One hundred eighty-eight patients with acute inferior myocardial infarction who received thrombolytic therapy were enrolled in this study. The magnitude and location of ST segment depression in noninfarcted leads and the maximum ST segment elevation (STEmax) in inferior leads were measured. All patients were divided into two main groups according to the presence of RSTD and five subgroups according to the location of RSTD, the maximum RSTD and the STEmax. The coronary angiography was performed in all patients 28 +/- 4 days after acute myocardial infarction. RESULTS: There were no significant differences in the proportion of coronary disease risk factors in patients with, versus those without, RSTD (P=0.6). Multivessel CAD was present in 63 of the 108 (58%) patients with RSTD and in 32 of the 80 (40%) patients with no RSTD (P=0.02). According to the location of reciprocal changes, multivessel disease was present in significantly more patients with anterior RSTD concomitant with or without lateral ST segment depression (P=0.01 and P=0.03, respectively); the proportion of single vessel disease was greater in patients with only lateral RSTD (P=0.02). In addition, the presence of anterior RSTD to a greater magnitude than the STEmax in inferior myocardial infarction increases the likelihood of multivessel disease (P=0.006). CONCLUSIONS: The presence of RSTD during an acute inferior myocardial infarction correlates with the presence of multivessel CAD and may not be only an electrical phenomenon.