Left Ventricular Regional And Global Function Evaluated By Two-Dimensional Speckle Tracking Imaging In Patients With Myocardial Ischemia

Objective: To measure the left ventricular(LV) longitudinal strain(LS)，circumferential strain(CS), radial strain(RS) and rotation，torsion index inpatients with coronary stenosis of the left anterior descending coronary artery(LAD) by two-dimensional speckle tracking imaging(STI), analysis thechanges of these indexes by comparative study with normal control group. Toevaluate the clinical value of STI in diagnosis of coronary artery disease(CAD)of myocardial ischemia.Methods: There were92hospitalized patients from Department ofCardiology, the Affiliated Hospital of Logistics College of Chinese People’sArmed Police Forces of which there were fifty men and forty-two women atthe age of forty-five to seventy-five. They were sorted by the outcome ofcoronary artery angiography(CAG). There were twenty male and seventeenfemale patients in the normal control group whose coronary arteries werenormal. Meanwhile thirty men and twenty-five women were included in casegroup whose LAD were abnormal with stenosis. Their ages ranged fromforty-six to seventy-two with a meanage(year,59.0±8.1). They were dividedinto three groups according to the stenosis degrees of LAD: there werethirteen men and eleven women in LAD mild stenosis(<50%) group; eightmen and six women in LAD moderate stenosis(50~75%) group; nine men andeight women in LAD severe stenosis(76~99%) group. There were no statisticdifferences in these groups in gender composition, age, blood pressure, bloodsugar and blood fat (P>0.05).Philips iE33ultrasound diagnostic system were applicated. Patients takenleft side, telling to be calm breathing, with body electrocardiogram(ECG)connected, recording ECG. High frame frequency two-dimensional images with frame frequency of60~70frames/s were imaged and recorded fromparasternal LV short axis view (mitral valve level, papillary muscle level,apical level); as well as the apical four-chamber view，three-chamber view andtwo-chamber view of the LV. The LV wall from parasternal short axis view inmitral valve level is equally to the basal segment of LV in the apicalfour-chamber view; the papillary muscle level equals to the middle segment;and the apical level to the apical segment. The peak systolic longitudinal strain(LSp)，the peak systolic circumferential strain (CSp)， the peak systolic radialstrain (RSp) of the eighteen LV segments were measured by STI，which are thebasal segment, the middle segment and the apical segment of the anteriorinterventricular septum(AS), the anterior wall(ANT), the lateral wall(LAT),the posterior wall(POST), the inferior wall(INF) and the posteriorinterventricular septum(PS). And these were also measured，which were theglobal peak longitudinal strain(GPLS), the global peak circumferentialstrain(GPCS), the global peak radial strain(GPRS), the peak basalrotation(PBR), the peak apical rotation(PAR) and the LV torsion(LVtor) whichis the subtraction of PAR and PBR.Results:1. In LAD of severe stenosis group, the LSps in many segmentsdecreased compaired with normal control group, which are basal, middle andapical segments of the AS, the ANT and the LAT, apical segments of thePOST, middle and apical segments of the INF and PS. The CSps in walls ofmiddle and apical segments of the AS, LAT and PS, basal and middlesegments of the ANT decreased. The RSps in regions of basal, middle andapical segments of the AS, the ANT, the LAT and the PS, apical segments ofthe INF reduced. The GPLS、GPCS and GPRS all reduced. The PAR, absolutevalue of PBR, LVtor all increased. All of the above parameters had significantstatistics(P<0.05). The LSps in apical segments of the AS, basal, middle andapical segments of the ANT, middle and apical segments of the LA and the PS;The CSps in middle and apical segments of the AS and PS, basal and middlesegments of the ANT; The RSps in basal, middle and apical segments of theAS and the ANT, apical segments of the LA and the INF, middle and apical segments of the PS; The GPLS and GPRS all decreased significantly(P<0.01).The LVtor increased significantly(P<0.01).2. In LAD of middle stenosis group, the LSps in middle and apicalsegments of the AS and the ANT, apical segments of the PS and the LAdecreased. The CSps in middle and apical segments of the AS, basal andmiddle segments of the ANT decreased. The RSps in basal and middlesegments of the AS, basal, middle and apical segments of the ANT, apicalsegments of the LA reduced. All of the above parameters had significantstatistics(P<0.05).3. In LAD of mild stenosis group, all of the indexes had no significantdifference(P>0.05).Conclusion:1. The regional strains decreased when the coronary arterieshad severe and middle stenosis, while there were no reduce in coronaryarteries with mild stenosis. It suggested that there was reduction of regionalmyocardial function in coronary arteries with severe and middle stenosis andthere was no function impairing when the coronary arteries had mild stenosis.2. The global strains were significant decreased in coronary arteries withsevere stenosis, while there were no significant difference when the coronaryarteries had mild and middle stenosis. Compaired with no changement of theLVEF, The decrease of the global strains might indicate earlier that there issevere coronary stenosis.3. The angles of left ventricular rotation and torsion increased when therewas severe stenosis in coronary arteries, which is benefit for early evaluationof reduction of regional and global myocardial function when there ismyocardial ischemia caused by severe coronary stenosis.4. The regional and global myocardial function can be evaluatedaccurately, objectively and with no trauma by STI. It shows the decrease ofregional and global myocardial function caused by severe and middlecoronary stenosis when there are no wall motion abnormalities inconventional echocardiography by STI, which is good for early detection,early diagnosis and early treatment of myocardial ischemia.