Research Of Characteristics Of Myocardium Asynchrony In Patients With Ischemic Cardiomyopathy By Tissue Synchronization Imaging

Chronic heart failure (CHF) is a kind of common syndrome. Its clinical symptoms are caused by left ventricule enlargement, heart function deterioration and cardiac output decrease. Clinical symptoms of some patients are aggravated because of the following delay of atrioventricular conduction and intraventricular conduction.With the increasing incidence of coronary heart disease (CHD), incidence rate of ischemic cardiomyopathy (ICM) is increasing. Curative effect,survival time and prognosis of ICM get worse than that of nonischemic heart failure.At present,the clinical application of percultaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG) is common in patients with ICM.At present, cardiac resynchronization therapy (CRT) in CHF patients is an alternative treatment in patients with electrocardiogram delay, sever, drug-refractory heart failure, which can improve haemodynamics, clinical symptoms, quality of life, and exercise tolerance in patients with severe congestive heart failure (CHF). However, about 20%~30% patients do not respond to CRT. These considerations suggest that the surface electrocardiogram may not be the optimal marker to select candidates for CRT.Quantitative tissue velocity imaging (QTVI) is a new echocardiographic technique aiming to noninvasively assess the ventricular wall motion, which has better spatial and temporal resolution.Tissue synchronization imaging (TSI), a new echocardiographic approaches, is superimposed on the routine two-dimensional echocardiographic images to provide visual mechanical information on the anatomical regions. TSI is a tissue Doppler approach to automatically detect peak positive velocity and then colorcode the time to peak velocities in green for normal timing, yellow-orange for moderate delay, and red for severe delay in time to peak of longitudinal velocity. However, TSI assessment during CRT may not be a routine procedure before standardized selection criteria have been defined. Further studies are needed to fully appreciate the clinical importance of these issues. There are two parts of the study. The first part is to study cardiac intervals, myocardial performance index (MPI) and Z index by quantitative tissue velocity imaging (QTVI) in normal subjects and patients with ischemic cardiomyopathy (ICM), and to investigate the prognostic value of QTVI. The second part is to explore the characteristic of myocardium asynchrony in normal subjects and patients with ICM by TSI. The aim of it was to assess whether TSI is useful predict synchronicity and can explore the characteristics and reasons of ventricular systolic and diastolic mechanical asynchrony in patients with ICM. Part One:The research of cardiac intervals and myocardial performance index in the patients with ischemic cardiomyopathyObjectives : To study cardiac intervals, myocardial performance index (MPI) and Z index by quantitative tissue velocity imaging (QTVI) in patients with ischemic cardiomyopathy (ICM), and to investigate the prognostic value of QTVI.Methods:Twenty-two ICM patients (ICM group) and 22 normal subjects (normal group) were studied by QTVI. Cardiac intervals were measured in the mitral annulets of different left ventricular walls, and MPI and Z index were also calculated.Results:The isovolumetric contraction time, isovolumetric relaxation time and atrial contraction time were longer than those in normal group(P<0.05); the ejection time and diastole filling time were shorter than those in normal group(P<0.05). Total left ventricular MPI in ICM group was significantly longer than that in normal group(P<0.001)and total left ventricular Z index in ICM group was significantly shorter than that in normal group(P<0.001).Conclusions:1. ICM caused both total and regional systolic and diastolic function impaired. QTVI is a rapid, non-invasive and sensitive method to quantitatively assess cardiac intervals and left ventricular function.2. QTVI can assess global left ventricular MPI and regional MPI of different segments. QTVI is a new way to assess Tei index.Part two: The research of characteristics of myocardium asynchrony in patients with ischemic cardiomyopathy by tissue synchronization imagingObjectives:The application of TSI can capture directly time information of different ventricular segments and Q-analysis of TSI can explore the characteristic of myocardium asynchrony in normal subjects and patients with ICM.The aim of it was to assess whether TSI is useful predict synchronicity and explore the characteristics and reasons of ventricular systolic and diastolic mechanical asynchrony in patients with ICM.Methods:It was assessed that 38 patients with ischemic cardiomyopathy (ICM), in which there were 26 patients without left bundle branch block (LBBB) (group B) and 8 patients with LBBB (group C). Control group(group A) included 26 normal healthy subjects.Using TSI, 14 points at basal and middle segments of posterior septum, lateral wall, inferior wall, anterior wall, posterior wall, anterior septum were investigated by apical 2- and 4-chamber and long axis views.Qualitative analysis:TSI can automatically detect peak positive velocity and then colorcode the time to peak velocities in green for normal timing, yellow-orange for moderate delay, and red for severe delay in time to peak of longitudinal velocity. Quantitative analysis: TSI studies were performed in each group. The average of systolic velocity peak (Vs) and early diastole velocity peak (Ve) were measured.All parameters were the average of 3 heart beats. The regional times to systolic velocity peak (Ts) and early diastole velocity peak (Te) were measured in 12 segments. Standard deviations of Ts (Ts-SD) and Te (Te-SD) of all 12 segments were calculated. Difference of Ts (Ts max-min) and Te (Te max-min) of all 12 segments were computed.Results:①The contral group included 364 segments,in which 334(91.8%) segments showed green(normal), 30(8.2%) segments showed yellow or orange(moderately-delayed) and without red one(severely-delayed). TSI became disordered in the ICM groups: In group B there were 364 segments in which 180(49.5%) segments showed green, 126 segments(34.6%) showed yellow or orange and 58 segments(15.9%) showed red. In group C there were 168 segments in which 72(42.9%) segments showed green, 48 segments(28.6%) showed yellow or orange and 48 segments(28.6%) showed red. The delayed segments in group B mainly located in lateral (80.8%), then in posterior and inferior wall.The delayed segments in group C mainly located in lateral (91.7%), then in inferior and posterior wall.②Assessment of systolic asynchrony in patients with ICM by TSI: Compared with control group, Left ventricular systolic asynchrony was common in patients with ICM. Ts,TS-SD,Ts max-min of LV 12 segments were significantly prolonged in all ICM groups compared with control group(P<0.05). Systolic asynchrony was more obvious in group C compared with group B. Ts of basal segments of left ventricular different walls and middle segments of inferior and posterior walls were longer in group C compared with group B (P<0.05), TS-SD,Ts max-min of group C were significantly greater than group B (P<0.05).③Assessment of diastolic asynchrony in patients with ICM by TSI: Compared with control group, Left ventricular diastolic asynchrony was common in patients with ICM. Te-SD,Te max-min of LV 12 segments were significantly prolonged in all ICM groups compared with control group(P<0.05).Te of group B was longer than control group, but it had no significant difference (P>0.05). Te of LV all segments except anterior septum were longer in group C than that of control group (P<0.05).Between group B and group C, Diastolic asynchrony was more obvious in group C compared with group B. Te of LV basal segments of lateral wall,posterior wall,inferior wall and posterior septum and middle segments of inferior and posterior wall were longer in group C compared with group B (P < 0.05).④Postsystolic Contraction (PSS): Compared with control group, PSS was common in patients with ICM. The group B included 364 segments,there were 118(32.4%) segments detected PSS. The group C included 364 segments,there were 94(56.0%) segments detected PSS. The segments of PSS in group B mainly located in lateral and the segments of PSS in group C mainly located in inferior and posterior wall.⑤Measurement of Vs and Ve by TSI: Compared with control group, Vs and Ve were significantly degraded in all ICM groups (P<0.05). Except middle segments of posterior septum Vs was faster in group C than that of group B (P<0.05), there was no significant difference in Vs of LV different segments(P>0.05). Except inferior wall Ve was faster in group C than that of group B (P<0.05), there was no significant difference in Vs of LV different segments(P>0.05).Conclusions:1. Left ventricular systolic and diastolic mechanical asynchrony is common in patients with ICM. Q-analysis and 2D of TSI are useful to predict synchrony of myocardium,to evaluate regional wall delay and to detect the latest region in systole.2. PSS is common in patients with ICM. PSS is a considerable agent to cause systolic and diastolic mechanical asynchrony.3. Systolic and diastolic mechanical asynchrony is more obvious in ICM patients with LBBB. CRT is obviously useful for ICM patients with serious congestive heart failure and intraventricular conduction block.4. TSI is a new technology which can analyze the movements of the ventricular wall qualitatively and quantitatively and can judge rapid and precise whether the movement is delayed. It is the optimal means to evaluate the characteristics of asynchronous myocardial contraction.TSI is important to prospectively select patients indicating for CRT, as well as to guide implantation and to evaluate post operation.