Usefulness of echocardiography in the prognostic evaluation of non–Q-wave myocardial infarction

Patients with non–Q-wave myocardial infarction (MI) are a heterogeneous population with a wide range of coronary disease severity and extent of myocardial necrosis, showing, therefore, different electrocardiographic findings and different outcomes. To evaluate the role of echocardiography in the management of non–Q-wave MI patients, 192 consecutive patients without previous MI were studied (78 with ST segment elevation, 56 with ST depression and 58 without ST modifications). All patients underwent 2-dimensional echocardiography (16-segment model) within 24 hours of admission to the coronary care unit. Wall-motion abnormalities, wall-motion score index, ejection fraction, and end-diastolic and end-systolic volumes were evaluated. In 35 patients, death, reinfarction, recurrent angina, or severe heart failure occurred during the in-hospital phase, whereas the remaining 157 patients had a good outcome. Patients with a poor prognosis were older (68 ± 6 vs 59 ± 5 years, p <0.01), had a worse left-ventricular function (wall-motion score index 1.4 ± 0.4 vs 1.25 ± 0.3, p <0.05; end-systolic volume 54 ± 25 vs 38 ± 12 mL/m2, p <0.01; ejection fraction 50 ± 10 vs 58 ± 8%, p <0.01), and presented more frequently with ST segment depression (49 vs 25%, p <0.01). The positive and negative predictive values for early clinical events were, respectively: ST segment depression 0.30 and 0.87; wall-motion abnormalities in >3 segments 0.28 and 0.86; wall-motion score index >1.33 = 0.28 and 0.87; end-diastolic volume >46 mL/m2 = 0.49 and 0.91; ST segment depression and wall-motion abnormalities in >3 segments 0.60 and 0.88. These results underline the usefulness of echocardiography in the early risk stratification of non–Q-wave MI patients, together with electrocardiographic data. Patients with ST segment depression and more extensive wall-motion abnormalities are at higher risk and their management needs a more aggressive approach.