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–Qwave 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, wallmotion 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 6 vs 59 6 5 years, p <0.01), had a worse left-ventricular function (wall-motion score index 1.4 6 0.4 vs 1.25 6 0.3, p <0.05; end-systolic volume 54 6 25 vs 38 6 12 mL/m2 , p <0.01; ejection fraction 50 6 10 vs 58 6 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 5 0.28 and 0.87; end-diastolic volume >46 mL/m2 5 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.