Velocity vector imaging (VVI) is a new echocardiographic technique of measuring regional myocardial velocities and deformation. Our aim was to evaluate the feasibility and accuracy of VVI in defining regional functional abnormalities in patients with an acute myocardial infarction.
Standard echocardiography and delayed enhancement (DE) magnetic resonance imaging were performed in 32 patients (29 men, mean age 61.2 +/- 8.1 years) within 36 hours of primary angioplasty. Twenty healthy volunteers (16 men, mean age 34.6 +/- 6.3 years) served as control subjects. Using VVI for offline analysis, segmental longitudinal deformation indices were measured. Infarcted, adjacent, and remote left ventricular segments were defined according to DE magnetic resonance imaging and coronary angiography. Infarct transmurality was also graded based on the DE extent within each segment on DE magnetic resonance imaging (0%-25%, 26%-50%, 51%-75%, and >76% of wall thickness).
As compared with remote segments, myocardial infarction segments had significantly lower longitudinal systolic strain (S) (-9.6% vs -14.6%, P < .0001), lower S rate (-0.75 vs -1.08 s(-1), P < .0001), and a higher postsystolic S index (21% vs 8.3%, P < .001). By receiver operating characteristic curve analysis, a myocardial peak systolic longitudinal S lower than -6.5% in at least one ventricular segment showed best predictive value (94%) for detecting an infarcted left ventricle. Peak systolic S and S rate were useful predictors of the presence of regional dysfunction, and for the localization and transmural extent of the infarct.
VVI is a promising new tool for studying myocardial motion and deformation with good feasibility in the clinical setting. The assessment of myocardial longitudinal systolic S and S rate with VVI can be used to identify the presence, location, and the transmural extent of myocardial infarction.