الفهرس 
Non Alcoholic Fatty Liver Disease (NAFLD)Only 14 pages are availabe for public view
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Abstract
Paralleling the epidemic of childhood obesity, pediatric nonalcoholic fatty liver disease (NAFLD) has emerged as a growing global health problem worldwide and is considered the most common cause of chronic liver disease in pediatrics, affecting an alarming number (38%) of obese children. NAFLD represents a spectrum of conditions that range from simple hepatic steatosis to potentially fatal non-alcoholic steatohepatitis (NASH) and cirrhosis. Both NAFLD and heart failure are obesity-related conditions with high cardiovascular morbidity and mortality that have reached epidemic proportions. Studies have shown that mortality among patients with NAFLD is higher than that in general population, mainly due to cardiovascular disease (CVD) and liver dysfunction. In fact, patients with NAFLD are more likely to die from complications of CVD than from liver-related death. Growing evidence suggests that NAFLD is an independent risk factor for CVD and is associated with impaired endothelial function, a higher prevalence of vulnerable coronary plaques, and with unfavorable levels of markers of subclinical atherosclerotic disease, including increased carotid intima media thickness and coronary artery calcification. Given that NAFLD and metabolic syndrome features often coexist, any relationship between NAFLD and cardiac remodeling and dysfunction may be moderated by visceral adipose tissue volume, obesity, or other cardiometabolic risk factors. Conventional echocardiography provides assessment of the cardiac structure, function and hemodynamics. Myocardial strain imaging is an emerging technique introduced for the assessment of regional myocardial function. It has increasing clinical applications and can be derived either with Tissue Doppler Imaging (TDI) or speckle tracking. The recently developed two-dimensional speckletracking echocardiography (2D-STE) method has enabled a simple and angle-independent evaluation of the LV deformation in the longitudinal, radial, and circumferential directions. Previous studies have indicated that 2D-STE is more sensitive than conventional echocardiography in detecting subclinical ventricular dysfunction in various clinical disorders.. Recently, it has become possible to perform real-time 3D echocardiography. This method allows quantification of both LV and LA volumes correlating closely to those measured by cardiac magnetic resonance; thus, this may become the standard method to calculate LVEF in the future. In the early 1970s, Dekker et al. were among the first to pursue three-dimensional (3D) reconstruction of two-dimensional (2D) echocardiography (2DE) images. In the following three decades, the results of these investigative studies done to validate the utility of reconstructive 3DE for assessing cardiovascular structure, flow, and function were published. Although it was a big revolutionary concept, reconstructive (3DE) did not become a widely accepted clinical tool for the evaluation of congenital heart disease (CHD) until the early 2000s, when technological advances led to the advent and commercialization of speckle tracking three-dimensional echocardiography (ST-3DE)) that has overcome several limitations of 2D STE. Speckle Tracking Echocardiography (STE) is an echocardiographic imaging technique that analyzes the motion of tissues in the heart by using ultrasonic sound waves to generate interference pattern and natural acoustic reflections. These reflections, described as ‗‗speckles‘‘, are tracked consecutively frame to frame and ultimately resolved into angle-independent 2D and 3D strain-based sequences. These sequences provide both quantitative and qualitative information regarding tissue deformation and motion.ST-3D provides rapid image acquisition and does not require high level of operator skills, and with a shorter scan time, the technique has the potential to increase the efficiency in the echo laboratory. LV deformation as measured by longitudinal, radial, and circumferential strain is thought to be closely linked with the myofiber architecture. The RV myocardial layer consists of a characteristic myocardial fiber orientation in which the longitudinal fibers in the subendocardial layer gradually change to a circumferential direction in the midwall layer and revert to longitudinal in the subepicardial layer. Two- dimensional speckle tracking echocardiography allows quantitative measurements of regional deformation as strain in clinical and animal experimental settings. The aim of this study was to evaluate subclinical right ventricular dysfunction using the 2-dimensional speckle tracking echocardiography of the three myocardial layers in a group of overweight/obese children and adolescents with ultrasound proven NAFLD and correlate the right ventricular longitudinal strain (LS) with clinical, metabolic, cardiac marker (troponin I) and other echocardiographic parameters. Patients and Methods It was conducted upon: three groups of children. The first group comprised 40 overweight/obese children and adolescents with ultrasound proven NAFLD The second group involved 20 overweight/obese children and adolescents of matched age, sex, and BMI with normal levels of liver enzymes and lipid profile, with no evidence of steatosis by ultrasonography, Whereas the third group included 20 healthy children of matched age and sex as a healthy control group. Diagnosis of NAFLD was based on the finding of hepatic steatosis detected by abdominal ultrasonography and appropriate exclusion of other causes of fatty liver.