| Part one Studying normal left ventricular wall movement byquantitative tissue velocity imagingObjective: To investigate the asynchrony of left ventricular (LV) wall motion during LV systole, early diastole and left atrial (LA) systole and to find the relationship between the asynchrony and LV relaxation, basing on exploring the characteristics of normal LV wall movements and analyzing the difference of moving phase between regions of LV wall; to investigate the movement of LV myocardia during isovolumetric relaxation (IVR).Methods: Thirty-six healthy subjects who entered the study were divided into two groups according to the Doppler spectra of transmitral flow, group A (E/A>1) and group B (E/A<1). Three standard apical views (two-chamber, four-chamber and apical long-axis) and parasternal long-axis view were acquired by quantitative tissue velocity imaging (QTVI). Digital loops of three cardiac cycles were collected. LV in each apical view was dividedinto two walls, each of which was subdivided into four levels (annular, basal, mid, and apical). Posterior wall in parasternal long-axis view was subdivided into three levels as base, mid and apex. The sample volume was subsequently placed on middle myocardia of all the levels of every LV wall and then the time-velocity curves were obtained. TR-s(interval between R-wave of ECG and peak of s wave on time-velocity curves), TR-e(interval between R-wave of ECG and peak of e wave on time-velocity curves) and TR.a(interval between R-wave of ECG and peak of a wave on time-velocity curves) were measured. Ts1 (mean difference of TR-S between adjacent levels of every wall), ATs2(mean difference of Tr.s between opposite walls of every level), SDR.s(standard deviation of all levels TR.S), @TS3 (mean difference of Tr_s between adjacent levels of posterior wall in short-axis direction), @TS4 (mean difference of Tr.s between long- and short-axis directions in the same level of posterior wall) were used to evaluate the synchrony of LV systole. So were @Te1, @Te2, @Te3, SDr-e @Te4 and @Ta1, @Ta2, @Ta3, SDR-a, @Ta4. The velocities of systolic movement(IVR+) and diastolic movement(IVR-) during isovolumic relaxation were measured. All variables were compared with each other among different levels and different groups. Correlations between all variables and ages were analyzed respectively.Results: I . Annular Tr.s was smaller than other levels' significantly. TR-e and Tr-a showed significant increasing trend from annular to apical level. Basal and mid TR-e of posterior wall in long-axis direction were larger than those in short-axis direction. Basal, mid and apical TR-e in group A were smaller than those ingroup B. II. All the variables used to evaluate the asynchrony of early diastole correlated significantly with age respectively and those in group A were smaller than in group B. There was no significant correlation between all the variables used to evaluate the asynchrony of systole and age, and no significant difference of the variables was found between groups. Neither were the variables used to evaluate the asynchrony of late diastole except that @Ta3 and @Ta3/T in group A were smaller than in group B significantly. IE.There were five types of motion during IVR and the frequency of movement in diastolic direction(IVR-) were highest. The peak velocity of IVR- showed significant increasing trend from base to apex. Velocities of mid and apical IVR- in group A were larger than in group B. In 0.40% of all segments in group A and 8.19% of all segments in group B, the peak velocity of IVR- was larger than that of e wave(IVR-/e>l). There were significantly different frequencies of IVR-/e>l between two groups. IV. There was no difference of peak movement velocities along systolic direction during IVR (IVR+) among levels and no correlation was found between peak velocity of IVR+ and age. The frequency of segments which showed IVR+/s>0.2 was significantly less in group A than that in group B.Conclusions: Normal LV wall do not contract and relax in a absolutely uniform manner.
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