| Viral myocarditis is a common cardiovascular disease.It is difficult to diagnose for its nonspecific clinical manifestations . Infectious agents cause myocardial damage by two basic mechanisms:invasion of the myocardium and immunologiclly. Endothelial cells are involved in the modulation of platelet activation, leukocyte adhesion, and thrombosis. The endothelium, therefore, delicately balances the counterregulatory pathways that control vasomotion, cell proliferation, thrombosis, inflammation. Well-known cardiac risk factors, including age, gender, hypertension, hyperlipidemia, diabetes mellitus, and smoking, as well as novel risk factors, such as inflammation and hyperhomocystinemia, have been associated with abnormal vasorelaxation. Pharmacological therapies and lifestyle changes aimed at improving cardiovascular risk, in many instances, may also improve vasomotor function. In this study we find that the impairment of the brachial atery endothelial function in viral myocarditis by using high resolution ultrasound.The non-invasive assessment of flow-mediated dilation and glyceryl trinitrate-mediated dilation in the brachial artery can be used as a kind of methods to measure endothelial function of the viral myocarditis individuals.Objective:To explore the endothelium-dependent and endothelium independent vasodilator changes in viral myocarditis by ultrasonography.Method:In this investigation we monitored the 70 patients who came to thethird medical college of jilin university during 2005-2006. The patients were divided into 3 groups:the viral myocarditis group,the non myocarditis group,the normal control group. The viral myocarditis group have 30 cases in all, 17 cases were men, 13 cases were women.They were 17 to 35 years old,the mean age was 25.1 years old. These patients have more or less upper respiratory infection or diarrhea history with fervescence before sick in three weeks and they have different kinds of debilitation,palpitation,chest distress,accelerated breathing ect, as well as decreased loudness of first sound and various kinds of arhythmia, ECG changes(ST-segment or T-wave deviations); Coxsackie virus B specific antibody IgM detection (+)in peripheral blood ; Serum markers of cardiac damage are myocardium zymogram and troponin I. The non myocarditis group have20 cases,11 cases were men,9 cases were women.They were 19-36 years old.The mean age was 25.7 years old . These patients also have more or less upper respiratory infection or diarrhea history with fervescence before sick in three weeks, but they can not be diognosed as acute viral myocarditis. The normal control group have 20 cases,12 cases were men,8 cases were women.They were 18-32 years old.The mean age was 23.9 years old. The patients in the non myocarditis group and the normal group have not coronary heart disease,diabetes-mellitus,hypertension,smoking.Echocardiography and electrocardiograms were normal.The three groups have no distinct difference in blood pressure,sex, age, cholesterdemic, high density lipoprotein triglyceride,low density lipoprotein cholesterol (P>0.05).All patients underwent the measurement of the brachial artery basic diameter,flow-mediated dilation and glyceryl trinitrate-mediated dilation.All data was delivered through means value±standard errand( X±S).We analyzed the two groups through t test.Results:(1)The brachial artery basic diameter: the viral myocarditis group is3.54±0.51mm,the non myocarditis group is 3.56±0.54mm,the normal control group is 3.55±0.38mm. The three groups have no distinct difference.(2)Flow-mediated dilation: the viral myocarditis group is (8.73±2.87%),the non myocarditis group is (13.00±2.79%),the normal group is (19.32±2.67%).the FMD of the viral myocarditis group and the non myocarditis group were decreased than that of the normal control group,and they have distinct difference(p<0.01). the FMD of the viral myocarditis group was decreased than that of the non myocarditis group, and they have distinct difference(p<0.01).(3) Glyceryl trinitrate-mediated dilation: the viral myocarditis group is(19.68±5.84%),the non myocarditis group is (23.18±4.28%),the normal control group is (24.24±4.13%). The three groups have no distinct difference.(p>0.05).(4) The comparison of diagnose efficacy and critical value analysis about ROC plot to CK-MB and FMD : the area under the curve of ROC plot to FMD is 0.924,the CK-MB is 0.843,the difference have statistical significance .what critical value we take is the maximal cum about sensitivity and specificity.the best critical value of FMD is about 10%,the sensitivity is 92.5% and the specificity is 77.6% at this time. .the best critical value of CKMB is about 4.26g/L, the sensitivity is 87.5% and thespecificity is 76.7% at this time.In all, we can presume the viral myocarditis is associated with endothelial dysfunction. The measurement of endothelial dysfunction have significant clinical sense to early diagnosis of the viral myocarditis.,and endothelial dysfunction is independent predict factor to the cardiovascular events.So that,endothelial function testing can provide prognostic value in viral myocarditis. The testing of the endothelium might prove valuable in monitoring the response to various forms of therapies. The non-invasive assessment of endothelial function is very important to the early diagnosis and therapy in viral myocarditis and reverse the impairment of endothelial function and it is very cheap and convenient to operate. So the high-resolution ultrasound accessment can be used as a kind of method to provide the early diagnosis and prognostic value in viral myocarditis patients endothelial function testing. |
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