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Study of Left Ventricular Asynchrony in Children with Congestive Heart Failure by Quantitative Tissue Velocity Imaging

Author: HuaShaoHua
Tutor: QinShiCheng
School: Zhengzhou University
Course: Medical Imaging and Nuclear Medicine
Keywords: Child Quantitative tissue velocity imaging Synchronous In children , heart failure , congestive Asynchronous
CLC: R445.1
Type: Master's thesis
Year: 2007
Downloads: 87
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Abstract

The first part: the synchronous movement of normal children myocardial tissue Doppler study of the background and purpose of the heart in order to achieve a normal pump function, must maintain AV synchrony, ventricular synchronization and coordinated motion between the wall of each segment. Excited maintain normal heart contraction sequence of each segment of the left and right ventricles and ventricular electromechanical synchrony to maintain cardiac efficient scheduling of blood is the most important premise. The study found that coronary heart disease, hypertrophic cardiomyopathy, bundle branch block and dilated cardiomyopathy patients are to different degrees of myocardial asynchrony phenomenon, especially a variety of structural heart disease caused by the late congestive patients with heart failure, myocardial asynchronous phenomenon is even more serious. Intraventricular dyssynchrony, ventricular wall uncoordinated contraction, even paradoxical wall motion, resulting in the reduction of contraction; sparking synchronization causes ventricular diastolic left ventricular filling time, myocardial invalid movement and mitral regurgitation, thereby increasing the deterioration of heart function. Traditional evaluation of myocardial asynchrony isotopes, MRI, ECG, traditional M-mode and two-dimensional echocardiography, both its application is limited due to their own characteristics. Quantitative tissue velocity imaging (QTVI) in the direction of the longitudinal axis of the movement of the heart, the same heart cycle at any moment multi-site measurement and analysis, combined with the ECG, myocardial motion time indicators can reflect more fully the synchronous movement of the assessment of myocardial advantage. In this study, the use of quantitative tissue velocity imaging technology (QTVI) of normal children myocardial synchronization movement indicators were measured to investigate the normal pediatric cardiac synchronization laws of motion. Materials and Methods 100 cases of normal children, 50 males and 50 female, age 1 -14 years old, on average (7.5 ± 2.9) years. Acquisition apical four-chamber apical two-chamber view dynamic images were recorded in color Doppler tissue velocity imaging conditions after the interval and left ventricular sidewalls (apical four-chamber view); (two-chamber apical left ventricular anterior and inferior wall concept) of myocardial motion information, ECG tracings. The four walls of the left ventricle is divided into base, intermediate and apical segments of three parts, namely the sampling point at the valve ring and the basal segment, basal and middle segments of the middle section and apical segments of the junction of subendocardial myocardial layer, to obtain the the the four wall 12 the sampling points QTVI curve, apical four-chamber view and take the right ventricular wall subendocardial sports QTVI curve in the annulus and the basal segment of the junction. QRS wave on the the measurement each sampling point QTVI curve from the start to the the TS and Te of the peak systolic velocity and early diastolic peak velocity time limit. TS: on behalf of the the myocardial electrical - mechanical contraction time; Te: represent myocardial electricity - mechanical relaxation time. Results 1. The synchronization of the movement of the left ventricular myocardium of normal children the same wall three segments TS measured value was no significant difference (P> 0.05); addition to the interval between the walls and the front wall and the side wall and the lower wall Ts measured value their own significant difference (P <0.05) more than left ventricular various intramural Ts measured value difference is not statistically significant (P> 0.05); the Te measured values ??between the left ventricular wall and the segment was no significant difference (P> 0.05). 2. Basal segment of the right ventricular wall Ts the Te measured value of the basal segments of the right ventricular wall Ts values ??than Ts mean left ventricular wall basal segment delay (41.0 ± 15.7) ms (P <0.01); Te values ??and left The chamber 4 wall basal segment Te measured value was no significant difference (P> 0.05). 3. Influence factors Ts, Te measured values ??of the left ventricle of each segment of the Ts, Te measured value average, denoted as TS-M, Te-m. Stepwise multiple linear regression analysis with factors such as age, heart rate, blood pressure, body surface area. The results showed that the Ts-m negative correlation with heart rate; Te-m, heart rate and diastolic blood pressure were negatively correlated. Conclusion 1. Normal children the same in different segments within the wall myocardial systolic and diastolic movement is synchronized, but individual wall between physiological circumstances synchronous contraction there are certain differences, which may be a feature of the children's; 2. The study found that children with left ventricular septal and anterior wall the Ts time frame a little longer on the side wall and bottom wall, and QTVI curve systolic waveform than blunt (Figure 2) are different from adults. The possible causes of the chambers of the heart in children is still in developmental stages, the left and right side of the pressure contrast, some differences related to the size of the heart chamber volume and adults, but the exact mechanism remains to be further explored; 3. Movement is basically between the left and right ventricles of normal children, but there are some differences in the peak time. Part II: asynchronous movement of children with heart failure heart tissue Doppler Background and Purpose congestive heart failure (congestive heart failure, CHF) is the end stage of the development of a variety of heart disease in patients with reduced quality of life, survival time short, high mortality, has been the problem of medical treatment. Cardiac resynchronization therapy (cardiac resynchronization therapy CRT) is an effective method of an emerging non-drug treatment of heart failure. CRT preoperative evaluation of ventricular mechanical contraction synchronization, select appropriate patients, as well as the efficacy of CRT after become a hot topic in today's research. Contraction dyssynchrony evaluation based on echocardiography increasingly become screening CRT therapy patients and predict CRT therapy reflect a very valuable technology. Quantitative tissue velocity imaging (quantification tissue velocity imaging, QTVI) is the basis of the DTI technology development, real time access to the myocardial segment movement all the information, overcoming the traditional DTI technology in pulsed Doppler analysis of myocardial motion can only observe a certain point the drawbacks of myocardial motion, and indicators measuring time by the method measuring velocity curve derived easily, accurate and repeatable than traditional method more sensitive, more convenient and faster. In this study, quantitative tissue velocity imaging (QTVI) detection of CHF in children with left ventricular synchronous movement indicators, aimed at (1) observation the CHF of children with left ventricular non-synchronous movement; ② explore CHF in children with left ventricular myocardial asynchronous movement of left ventricular function, QRS duration, left ventricular remodeling and mitral regurgitation and other relationships. Materials and methods CHF 30 cases in children, 17 males and 13 females, aged from 8 months to 14 years old, on average (6.5 ± 4.3) years. Center intimal fibroelastosis 3 cases, dilated cardiomyopathy 16 cases, 8 cases of viral myocarditis, myocardial densification insufficiency in 3 cases. Heart function Ⅱ - Ⅳ grade. Normal control group of 40 cases, 20 cases, men and women aged 9 months to 14 years, mean (6.8 ± 2.6) years old, age-matched. Instrument company GE Vivid 7 color Doppler ultrasound probe frequency of 3.0MHz. Acquisition apical four-chamber apical two-chamber view dynamic images were recorded in color Doppler tissue velocity imaging conditions after the interval and left ventricular sidewalls (apical four-chamber view); (two-chamber apical left ventricular anterior and inferior wall concept) of myocardial motion information, ECG tracings. The four walls of the left ventricle is divided into base, intermediate and apical segments of three parts, namely the sampling point at the valve ring and the basal segment, basal and middle segments of the middle section and apical segments of the junction of subendocardial myocardial layer, to obtain the the four wall 12 the sampling points QTVI curve, measuring the Ts and Te on each the sampling points QTVI curve starting from the QRS complex to the peak systolic velocity and peak early diastolic velocity time limit. Ts: representing the myocardial electrical - mechanical contraction time; Te: represent myocardial electricity - mechanical relaxation time. Between Ts and Te of the maximum difference in the three segments in the same wall (Intra-△ Ts and the Intra-△ Te) were calculated, and the maximum difference of the Ts and Te of the left ventricle in 12 myocardial segments (Max-△ TS and Max - △ Te). Intra-△ Ts and Intra-△ Te behalf of the different segments within the same wall asynchronous systolic and diastolic indicators; Max-△ Ts and Max-△ Te behalf of the non-synchronous global left ventricular systolic and diastolic indicators. Left ventricular function indicators and other indicators include: ① left ventricular ejection fraction (LVEF); ② left ventricular work index-Tei index; ③ aortic ejection period (QA), the the pulmonary ejection period (QP) and its difference ( Q-AP). ④ the left ventricle after the interval, sidewalls, anterior and inferior mitral annular systolic and early diastolic peak velocity Vs and Ve mean (Mean Vs Mean Ve); ⑤ left ventricular diastolic end diameter (LVEDd); ⑥ left ventricular sphericity index (LVSI), left ventricular transverse diameter and length ratio; ⑦ reflux area ratio (MRA / LAA), mitral regurgitation jet area and left atrial area ratio; ⑧ QRS intervals period. Results 1. No significant differences between the control group children and CHF group age (P> 0.05); heart rate, QRS duration, Tei index, LVEF difference between the two groups was significant (P <0.01). 2. The CHF group Intra-△ Ts and Intra-△ Te value significantly greater than the normal control group, a significant difference (P <0.01); The CHF group Max-△ Ts and Max-△ Te values ??significantly greater than the normal control group, there is a significant difference (P <0.01); 4. The CHF group Mean Vs Mean Ve value significantly greater than the normal control group, there is a significant difference (P <0.01); The CHF group Max-△ Ts with LVEF negative correlation (r = -0.54, P <0.05), and Tei index positive correlation (r = 0.58, P <0.01) and QRS irrelevant. The Max-△ Te QRS positive correlation (r = 0.57, P <0.05), and LVEF, Tei index is not relevant. 6. The CHF group QA, QP, Q-AP values ??significantly greater than the normal group, there is a significant difference (P <0.01). Conclusion 1. Asynchronous myocardial contraction and relaxation of movement of children with heart failure not only exist in the same segment, different intramural and exist in different segments within the same wall, non-synchronous movement in left ventricular widespread, similar to adults. 2. CHF in children with left ventricular systolic to asynchronous movement with left ventricular ejection fraction, systolic mitral annular average speed and left ventricular end-diastolic diameter closely related; the diastolic asynchrony early diastolic mitral annulus average speed, two sharp regurgitation area ratio close relationship. Asynchronous left ventricle systolic and diastolic movement can affect heart function and left ventricular remodeling, and leads to mitral regurgitation. 3. Between the right and left ventricles of CHF in children, there are also the obvious dyssynchrony can further damage the heart function of children. 4. QRS duration is a traditional evaluation of ventricular synchrony movement indicators, the study shows that QRS duration with myocardial asynchronous diastolic indicators.

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