الفهرس 
Assessment of left ventricular systolic function by cardiac ultrasoundOnly 14 pages are availabe for public view
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Abstract
One of the earliest applications of clinical echocardiography was the evaluation of left ventricular (LV) size and function. The accuracy of the determination of global and regional LV function with echocardiography has improved as the technology has matured (Picard et al., 2008).
Although conventional echocardiography is considered to be reliable for ventricular wall motion analysis and assessment of regional myocardial function, the visual estimation of wall motion is very subjective and therefore highly operator dependent. It also has high interobserver and intraobserver variability and allows only limited evaluation of radial displacement and deformation, without the possibility of assessing myocardial shortening and twisting (Perk et al., 2007).
During recent years, velocity imaging, displacement imaging and deformation imaging (strain and strain-rate imaging) have emerged as valuable tools for more comprehensive and reliable echocardiographic assessment of myocardial function (Yu et al., 2007).
Initially myocardial deformation imaging became possible using tissue Doppler. More recently myocardial deformation imaging also become possible with myocardial speckle tracking using 2D echocardiography( Dandel et al., 2009).
Speckle-tracking echocardiography is a new non-invasive ultrasound imaging technique that allows for an objective and quantitative evaluation of global and regional myocardial function independently of the angle of insonation and the cardiac translational movements (Blessberger et al., 2010 & Sergio et al., 2011).
The aim of this study was to evaluate the global and regional left ventricular longitudinal systolic strain by 2D STE in a large group of healthy children across a wide age range to establish their reference values and to assess the influence of age, sex and hemodynamic factors.
This study was conducted at the Echocardiography Unit, Pediatric Department at Ain Shams University, over the period from November 2013 to February 2015 on 250 healthy children without any known cardiovascular diseases.
All children were subjected to detailed history taking laying stress on past medical history of clinical significance, family history of cardiovascular diseases in an early age and symptoms suggestive of any cardiovascular diseases.
Thorough clinical examination laying stress on anthropometric measurements (height and weight),general physical examination including blood pressure assessment and local cardiac examination.
ECG to exclude any cardiac electrical abnormalities, routine 2D echocardiography and M mode echocardiography to assess the left ventricle dimension and systolic function.
Also 2D speckle tracking echocardiography to evaluate myocardial function (global and regional).
This study included 250 healthy children, their ages ranged from 22 days to 16 years. Males were 56.4% while females were 43.6% with male to female ratio 1.3:1.
The study population was divided into 5 representative age groups, group 1 consisted of subjects from the neonatal period to just below 1 year (14 child, 5.6%); group 2 consisted of subjects aged 1 to just below 6 years(79 child,31.6%); group 3 consisted of subjects aged 6 to just below 10 years
(74 child, 29.6%); group 4 consisted of subjects aged 10 to just below 14 years (56 child, 22.4%); and group 5 consisted of subjects aged 14 to 16 years(27 child, 10.8%).
The mean values of weight, BSA and BMI showed statistically significant differences between males and females groups, while there were no statistically significant differences between males and females group regarding the mean values of heart rate, systolic blood pressure and diastolic blood pressure.
With increasing age- the anthropometric parameters of height, weight, body surface area (BSA), and body mass index (BMI) were all increased significantly and expectedly.
The mean values of global peak longitudinal systolic strain A2C, A4C, APLAX and average were (-22.2 ±2.5), (-21± 2.3), (-20.6± 2.4) and (-21.2 ±1.9) respectively.
There was no statistically significant difference between males (-21.2 ±1.9) and females (-21.3 ±1.8) regarding the mean value of the averaged global longitudinal systolic strain measured by 2D speckle tracking echocardiography.
There was a statistically significant positive correlation between age and the average global peak longitudinal systolic strain.
There was no statistically significant correlation between HR, blood pressure, BMI, BSA and the averaged global longitudinal systolic strain.
There was a statistically significant positive correlation between the averaged global peak longitudinal systolic strain and the LV dimensions (IVSD, LVPWS and ESV) assessed by M-Mode echocardiography.
Furthermore, there was a statistically significant negative correlation between the averaged global peak longitudinal systolic strain (AVG) and the EF and FS.
The mean values of longitudinal systolic strain were lower in the basal segments and became (significantly) more negative from base to apex as follows: the mean value of longitudinal systolic strain at basal segments was
(-20.7± 2.1), the mean value of longitudinal systolic strain at mid segments (-21.1± 1.8) and the mean value of longitudinal systolic strain at apical segments was (-21.9± 2.7).
Regarding M-Mode echocardiography findings, the mean values of LVIDd, LVIDs, AO, EDV, ESV and SV were higher among the male group (3.6±0.6) cm, (2.3±0.4) cm, (2.2±0.4) cm, (56.2±21.2) ml, ( 19.2±9) ml and (39.8±15.4) ml respectively when compared to the female group (3.5±0.6)cm, (2.2±0.4) cm, (2±0.4) cm, (51.9±19.7) ml, (16.6±7.6) ml and (36.1±14.9) ml respectively and the differences were statistically significant.
There was a statistically significant positive correlation between age and the left ventricular dimensions (IVSD, LVIDD, LVPWD, IVSS, LVIDS, LVPWS, AO, LA/AO, EDV, ESV, SV and FS) measured by M mode. While, there was no statistically significant correlation between age and EF.