| Objective:In recent years, with the new echocardiography techniques quick development, especially tissue synchronization imaging (TSI) technology and two-dimensional strain (2DS) imaging technique, which provide a new approach for the evaluation of the emergence of non-synchronous nature of myocardial motion and myocardial deformation lead to the decline of cardiac function. This study was designed to evaluate left ventricular systolic asynchrony and systolic function in patients with heart failure using tissue synchronization imaging technique and two-dimensional strain imaging technique, and analyze the correlation of systolic function and synchronization index, strain and synchronization index, and evaluate the clinical value of TSI and 2DS.Methods:30 patients with heart failure (case group) and 28 healthy volunteers (control group) were selected randomly. Using 3V probe collected two-dimensional gray dynamic images of continuous three cardiac cycles from apical four-chamber view, apical two-chamber view and apical long axis view. Left ventricular end-diastolic volume ( LVEDV ),left ventricular end-systolic volume(LVESV),left ventricular ejection fraction(LVEF)were measured by three-dimensional tri-plane cardiac function measurement software. Using 3V probe collected tissue velocity imaging dynamic images of continuous three cardiac cycles from apical four-chamber view, apical two-chamber view and apical long axis view. Time to systolic peak velocity (Ts) of 12 segments of left ventricular were recorded by using tri-plane TSI analysis software. The standard deviation(Ts-SD)and the maximum difference(Max-△Ts)of Ts were calculated based on Ts. Isovolumic contraction time (ICT), ejection time (ET) and isovolumic relaxation time (IRT) were measured using quantitative tissue velocity imaging (QTVI). Put the sampling volume on the valve ring of apical long axis view (APLAX), four-chamber view (A4C), and two-chamber view (A2C) respectively, and the motion curve of six ventricular walls were obtained. The duration of isovolumetric systolic wave, systolic S wave and isovolumetric diastolic wave were measured respectively. Tei index was calculated. Two dimension gray scale dynamic image of three continuous cardiac cycles from apical long axis view (APLAX), four-chamber view (A4C) and two-chamber view(A2C) were obtained. The valve ring and apex of left ventricular endocardium were labeled in systolic, and analyzed automatically with AFI analysis software of two-dimensional strain. Running the software, the position of each myocardial segment in region of interesting was detected with the cardiac cycle. The six left ventricular walls of three views were equally divided into basal segment, middle segment and apical segment (18 myocardial segments). The peak systolic strain of 18 myocardial segments,strain curve and the whole cardiac strain of each view were recorded by two-dimensional strain analysis software. After measurement of three views, the software will give out the bull's eye. All statistical analyses were recorded, and analyzed by SPSS13.0 for Windows. The results were expressed by means±standard deviation, inter-group comparison was tested by t-test. The correlation between similar indicators of cardiac function was analyzed by linear correlation analysis (P<0.05: statistical significance; P<0.01: significantly statistical significance).Results:(1) The case group had significantly larger Left Ventricular End-diastolic Volume and Left Ventricular End-systolic Volume than the normal control group. The Left Ventricular Ejection Fraction was lower in case group than in the normal control group(all P<0.05).(2) Tei index, ICT, IRT in case group were significantly longer than those in control group, and ET in case group was shorter than that in control group (P<0.05). (3) Peak velocity time in case group was significantly longer than that of control group. The time to systolic peak velocity of diseased segments were significantly longer than the normal segments in case group(P<0.01).(4) The control group included 336 segments, in which 276 segments were green (82%), 60 segments were yellow moderately-delayed (18%), and no red severely-delayed segments. There were 360 segments in case group, in which 158 segments were green (44%), 72 segments were moderately-delayed (20%) and 130 segments were severely-delayed (36%). (5) The systolic strain of 18 segments in case group was significantly lower than that of control group. The average GLS and GLS of APLAX, A4C, A2C of the case group were all lower than that of the control group. The strain of control group were increase gradually from basal segment to apical segment, and there were no statistic difference in each other ventricular walls. But the strain of case group lose this law. (6)The Ts-SD and Max-△Ts were negative correlated with LVEF measured by 3D-3 plane method, the correlation coefficient were -0.468,- 0.467, (P<0.05). The Ts-SD and Max-△Ts were positive correlated with Tei index, the correlation coefficient were 0.602, 0.494, (P<0.05).The Ts-SD was highly positive correlated with Max-△Ts, the correlation coefficient was 0.916, (P<0.01). The Ts-SD and Max-△Ts were highly negative correlated with GLS, the correlation coefficient were 0.58, 0.48, (P<0.05).Conclusions:The following conclusions from the results of this study: (1) The left ventricular systolic function is decreased and cardiac wall motion is not synchronized in patients with heart failure. TSI is a non-invasive investigation, which can quantitatively and qualitatively assess the synchronization of myocardium motion, and provide a more reliable basis for select and cure patients indicating for cardiac resynchronization therapy. (2) TSI can analyze myocardial systolic asynchrony by time to systolic peak velocity. The systolic coincident indexes were correlated with Tei index and LVEF which are all assessing left ventricular systolic function index. With the decrease of synchronism in heat failure, LVEF and Tei index are all change. It was consistent with using these indexes for assessing left ventricular systolic function and synchrony. (3) Global strain long axis in patients with heart failure were significantly lower than control group, the overall ventricular strain as the cardiac function parameter, can be more accurately and quantitatively evaluate left ventricular function. The strain was negative correlated with coincident index, and it was feasible and reliable for assessing left ventricular systolic function using two-dimensional strain imaging technique.In sum, TSI can response the synchronization of myocardial qualitatively and quantitatively. Two dimensional strain can response the degree of myocardial deformation well. They are combine and replenish each other. As a new method for assessing left ventricular systolic function, it can well evaluate the movement of left ventricular in patients with heart failure. It provides an important theoretical evidence for clinical treatment, and provide a development and supplementary for conventional echocardiography. |
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