RESUMO
BACKGROUND: Right ventricular (RV) involvement is associated with increased morbidity and mortality in patients with acute inferior myocardial infarction (MI). Although electrocardiography is probably the most useful, simple, and objective tool for the diagnosis of acute MI, there are no well-defined criteria in the standard 12-lead electrocardiogram to properly identify RV involvement in patients with acute inferior MI. Our objective was to evaluate the value of ST-segment depression in lead aVL in diagnosing RV involvement in patients with acute inferior MI. MATERIALS AND METHODS: Sixty-seven patients, hospitalized with acute inferior myocardial infarction, were included in this study. The diagnosis of acute inferior myocardial infarction was based on the clinical history, characteristic enzyme pattern of CK-MB values, and the appearance of ST-segment elevation > or = 1 mm in at least two of the leads (leads II, III, aVF). RV infarction was defined by ST-segment elevation > or = 1mm in lead V4R. ST-segment depression in lead aVL that is more than 1 mm was accepted as a diagnostic criterion for RV involvement in patients with acute inferior MI. RESULTS: Thirty-one patients had >1 mm ST-segment depression and 28 of them had right ventricular infarction according to lead V4R. Thirty-six patients showed < or =1 mm ST-segment depression indicating no right ventricular involvement but four of them also had right ventricular infarction according to V4R. CONCLUSION: More than 1 mm ST-segment depression in lead aVL was found to have high sensitivity (87%), specificity (91%), high positive and negative predictive value (90%, 88%, respectively), and high diagnostic accuracy (89%) in diagnosing RV involvement in patients with acute inferior MI. Therefore, by using a simple 12-lead electrocardiographic sign, ST-segment depression >1 mm in lead aVL, obtained on admission, it is possible to identify RV involvement in patients with acute inferior MI.