Quantification of Regional Left Ventricular Systolic Dysfunction in Patients With Coronary Artery Disease by Strain Rate Imaging

Objectives To detect and compare the systolic strain rate (SR) and strain in the infarct and ischemic myocardium by strain rate imaging (SRI), in order to explore the clinical value of SRI in evaluating regional left ventricular systolic dysfunction. Methods Patients with coronary artery disease were divided into angina pectoris (11 cases) and myocardial infarction (21 cases) groups. Twenty age-matched normal subjects served as the control group. Septal, lateral, anterior, inferior, anteroseptal and posterior walls of the left ventricle were respectively scanned using color tissue Doppler imaging (TDI). Then SR and strain curves were derived from TDI for basal, middle and apical segments of each wall. SRI parameters were: Systolic SR (SRsys), systolic strain (εsys) and maximum strain (εmax). Results Compared with normal segments, SRsys, εsys and εmax decreased significantly in the infarct and ischemic segments (P<0.01). Compared with ischemic segments, SRsys, εsys and εmax decreased significantly in the infarct segments (P<0.05). Conclusions SRsys, εsys and εmax measured by SRI can be used to quantitatively analyze regional left ventricular systolic dysfunction in patients with coronary artery disease, and aid in differentiating infarct from ischemic myocardium.

Characteristics of myocardial postsystolic shortening in patients with coronary artery disease assessed by strain rate imaging

Background Postsystolic shortening （PSS） has been proposed as a marker of myocardial dysfunction. Strain rate imaging （SRI） is a novel ultrasonic technique, allowing reliable and noninvasive measurement of myocardial deformation. The purpose of this study was to investigate the characteristics of myocardial longitudinal PSS by SRI in ischemic and infarct myocardium in patients with coronary artery disease, and to explore its clinical applicability. Methods Eleven patients with angina pectoris, 21 patients with myocardial infarction and 20 healthy subjects were included in the study. Apical four-, three- and two-chamber views were displayed; and septal, lateral, anteroseptal, posterior, anterior and inferior walls of the left ventricle were scanned, respectively. PSS strain （εpss）, the ratio of εpss and systolic strain （εpss/εsys）, the ratio of εpss and maximum strain （εpss/εmax） and the duration of PSS （Tpss） in ischemic, infarct and normal myocardium were analyzed. Results PSS was found more frequent in the ischemic and infarct segments compared with the normal segments （39% vs 22% and 56% vs 22%, respectively; both P〈0.01）. It was even more frequent in the infarct segments than in the ischemic segments （56% vs 39%, P〈0.01 ）. The absolute magnitude of εpss, εpss/εsys, εpss/εmax were significantly larger and mpss significantly longer in the ischemic and infarct segments compared with that in the normal myocardium （P〈0.01）. εpss/εsys, εpss/εmax were even larger and Tpss even longer in the infarct than in the ischemic segments （P〈0.01）. Conclusions PSS is a common and important feature of the ischemic and infarct myocardium. εpss, εpss/εsys, εpss/εmax and mpss as measured by SRI may be promising markers for the quantitative assessment of regional myocardial dysfunction in patients with coronary artery disease. εpss/εsys, εpss/εmax and mpss may be helpful in differentiating infarct from ischemic myocardium.

Strain rate imaging in assessing the size of acute ischemic myocardium in dogs

Background Since the size of ischemic myocardium is closely related with both global and regional function of the myocardium, it is of great significance to measure the size of ischemic myocardium with non-invasive methods. Methods Eleven mongrel dogs were subjected to occlusion of the left anterior descending coronary artery for acute ischemia. Strain rate imaging had M-mode of strain-rate （CAMM） curve pointed from the basal segment of the anterior wall to the basal segment of the inferior wall to detect the border of ischemia size. The strain rate （SR） defined the cut-off value of ischemic myocardium in a two-chamber apical view, and marked by the anterior and inferior wall on two-dimensional images respectively. Along the endocardium and epicardium, the ischemic size was curved on two-dimensional images by the trackball method and then compared with the pathologically ischemic size. And then longitudinal strain rates were compared in the cut-off value, adjacent non-ischemic and ischemic segments at which the cut-off point was defined by changing the curve M-mode of strain rate after ischemia. Results Linear correlation existed between pathology and strain rate ischemic size （r=0.884, P 〈0.001）. The SR parameters were lower in ischemia and cut-off point than in non-ischemic segments. The peak SRs of systole （SSR）, early diastole （EsR）, late diastole （ASR）, strain during ejection time （εet）, and the maximum length change during the entire heart cycle （Emax） in ischemic segments lowered （P〈0.05）. Time to onset of regional relaxation （TR） was prolonged （P=0.012）. Conclusion SR imaging can accurately assess the size of ischemic myocardium. Chin Med J 2009; 122（2）： 193-198