ST Depressed in Unstable Angina: Clinical and Prognostic Characterization

pp. 55-61

Abstract

Background ST segment depression in the initial electrocardiogram in patients admitted with unstable angina isa predictor of in-hospital events. Objectives The purposes of this study were to cliniclaly define the characteristics of patients with unstable angina and ST segment depression; and to identified risk subgroups in this population. Material and method It was analysed the initial electrocardiogram of 875 patients with unstable angina included in the ENAI study. Clinical, and electrocardiographic characteristics and outcome were analysed comparing ST segment depression. In patients with ST segment depression electrocardiographic characteristics were analysed as predictors of major events. Results 444 patients presented electrocardiogram with nor-mal ST segment and 218 with ST segment depression. ST segment depression patients were older (65 versus 61 years; p<0.001), with more prevalence of diabetes and hypertension and less previous aspirin use. They presented higher heart rate 83 versus 70 (p < 0.01) and more left ventricular hypertrophy 15 versus 7% (p < 0.01). Patients with ST segment depression presented higher in-hospital events 5.5 versus 2%, odds ratio 2,8, IC 95% 1.08-7.44 (p < 0.03). In patients with ST segment depression, left ventricular hypertrophy was a risk marker of acute myocardial infarction or death: 15.2% versus 3.8%, odds ratio 4.5, IC 95% 1.1-11.7 (p < 0.02). The combination of heart rate of less than 80 and ST segment depression > 4 mm was associated with an increased risk of events: a) in patients with left ventricular hypertrophy: 40% versus 4.3%, odds ratio14.6 (p < 0.02); b) in patients with no left ventricular hypertrophy 13.3 versus 1.9%, odds ratio 7.8 (p =0.014). In the multivariate analysis left ventricular hypertrophy was an independent predictor. Conclusions Patients with unstable angina and ST segment depression present a higher risk of in-hospital major events. Left ventricular hypertrophy, no high heart rate and amount of ST segment depression identified subgroups of poor outcome.