| ObjectiveMyocarditis is a local or diffusive inflammation in myocardium,which may be acute or chronic.It is classified as infectious and non-infectious,mostly caused by virus infection.The incidence of it increases year by year.Myocarditis is a common disease in children,especially infants and children under four years old,as well as the school-age children who are prone to get upper respiratory and digestive tract infection.The patients'conditions show differently.It mainly damages the myocardium,as well as the interstitial.The heart dilates with myocardial cell degeneration,myocytolysis and interstitial edema.The damage mostly involves left ventricular wall and interventricular septal wall.Acute myocarditis patients with lighter clinical symptoms have better prognosis than those with severe symptoms,and rehabilitate completely several months later.While patients with severe symptoms are not as good as the former after treatment,developing into chronic myocarditis or dilated cardiomyopathy,which have a continuous heart expanding with cardiac dysfunction,and minority of them dead in acute phase.The pediatric diagnostic criteria for viral myocarditis include clinical symptoms,imaging study changes,electrocardiogram changes and serological targets changes.Serological targets include Creatine kinase isoenzyme(CK-MB) and troponin I(cTnI).Two-dimentional echocardiography can provide us overall evaluation of the heart, includting the size,the ejection fraction of left ventricular,the presence of valvular regurgitation and pericardial effusion.It helps us follow up,observe the evolution of disease and assess the drug efficy and know the prognoses.Strain Rate Imaging as a new ultrosonic technology to evaluate the movement of ventricular wall,which is non-invasive,simple and quantitative orientation,could become an effective way to evaluate acute myocardial systolic and diastolic injury.CK-MB and cTnI have been used as specific targets on evaluating injury of myocardium and commonly accepted by clinical doctors.The assessment of Tissue Doppler imaging technique on myocardial injury needs further study.The purpose of the study is to assess the application value of the Strain Rate Imaging on pediatric viral myocarditis diagnose and the correlation analysis between the Strain Rate and the serological targets through the Strain Rate Imaging on the movement of left ventricular wall of the pediatric viral myocarditis.MethodsSubjectThe control group includes 20 healthy children(mean age 5.8±2.4 years)with normal heart structure,normal ECG and without virus infectious symptoms.The positive group includes 20 acute myocarditis children(mean age 5.4±4.1 years)diagnosed in Shengjing Hospital.Children with congenital heart disease,hyperthyroidism, malnutrition and overweight were excluded.The group were divided into two groups:Lower LVEF group includes 3 cases with fulminant myocarditis,4 with severe myocarditis and 2 with severe myocarditis and cerebral ischemia and hypoxia,Normal LVEF group includes 11 cases with upper respiratory infection and fever in prophase,chest tightness and pain and arrhythmia(tachycardia and premature beats),the X-ray of chest are normal.EchocardiographyStandard echocardiography in this study was performed by a Philips ie33 with probe S5-1 and 12-4.This instrument provides QLAB-SQ imaging analysis and processing software.The left ventricular eject fraction was calculated by single plane Simpson rule from apical four-chamber views.Tissue doppler imaging was obtained from standard LV apical view and apical four-chamber view which including the LV anteroseptal,posteroseptal,lateral wall and posterior wall.Four consecutive beats were Stored and QLAB-SQ software used to get the SR curves and analyze the movement of the segments we want.Serological targetsThe data of CK-MB and cTnI was collected from the clinical laboratory of Shengjing Hospital.The echocardiography and TDI of the children with acute myocarditis were collected when the CK-MB and(or) cTnI was high.Statistical analysisThe data were analyzed with the SPSS software(version 13.0).Summary data were expressed as mean value±standard deviation.Comparisons between the groups were performed with independent-sample t-test.A value of p≤0.05 was considered statistically significant.The correlationship between the SR and the serological targets was analyzed by using Spearman.Results1.There is no significant difference between the myocarditis group with normal LVEF and the control group on heart rate and thickness of left ventricular wall.When the LVEF of the myocarditis group was low,there was no significant difference on heart rate and thickness of anteroseptal between the myocarditis group and the control group,while the thickness of posteroseptal left ventricular wall,posterior,sidewall was significant difference.2.When the LVEF of the myocarditis group was mormal,compared with the control group,the PPssr of anteroseptal and posteroseptal interval was higher and the Dsr was no significant difference.3.When the LVEF of the myocarditis group was low,PPssr of three segments and Esr of four segments were significant different,compared with the control group.4.When Correlation Analysis were performed on each of the eight segments of the myocarditis group with CK-MB and cTnI,the result showed only the PPssr of posteroseptal interval was correlated with CK-MB.Conclusions1.There are significant different between the strain rate of the myocarditis group and the control group.Using Strain rate can evaluate local myocardial function on acute myocarditis group in segment,it is Quantitative orientation and more accurate than two-dimentional echocardiography and provides more information to clinical doctors.2.When myocarditis was not severe and without obvious two-dimentional echocardiography changing,Strain rate imaging can discover the abnormity of local myocardial function,it is a supplement to two-dimentional echocardiography diagnosis.
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