Strain echocardiography and wall motion score index predicts final infarct size in patients with non-ST-segment-elevation myocardial infarction.

BACKGROUND: Infarct size is a strong predictor of mortality and major adverse cardiovascular events after myocardial infarction. Acute reperfusion therapy limits infarct size and improves survival, but its use has been confined to patients with ST-segment-elevation myocardial infarction. The purpose of this study was to assess the relationship between echocardiographic parameters of left ventricular (LV) systolic function obtained before revascularization and final infarct size in patients with non-ST-segment-elevation myocardial infarction, as well as the ability of these parameters to identify patients with substantial infarction.

METHODS AND RESULTS: Sixty-one patients with non-ST-segment-elevation myocardial infarction were examined by echocardiography immediately before revascularization, 2.1+/-0.6 days after hospitalization. LV systolic function was assessed by ejection fraction, wall motion score index, and circumferential, longitudinal, and radial strain in a 16-segment LV model. Global strain represents average segmental strain values. Infarct size was assessed after 9+/-3 months by late-enhancement MRI, as a percentage of total LV myocardial volume. A good correlation was found between infarct size and wall motion score index (r=0.74, P<0.001) and global longitudinal strain (r=0.68, P<0.001). Global longitudinal strain >-13.8% and wall motion score index >1.30 accurately identified patients with substantial infarction (> or =12% of myocardium, n=13; area under the receiver operator curve, 0.95 and 0.92, respectively).

CONCLUSIONS: Echocardiographic parameters of LV systolic function correlate to infarct size in patients with non-ST-segment-elevation myocardial infarction. Global longitudinal strain and wall motion score index are both excellent parameters to identify patients with substantial myocardial infarction, who may benefit from urgent reperfusion therapy.