| BackgroundHeart failure, frequently diagnosed in clinical practice, is the end-point of many cardiovascular diseases and is a syndrome incorporating complex etiology. Once the diagnosis is made, the patients are subjected to frequent readmission and poor prognosis. Not only the decline of heart function but also the sophisticated neuroendocrine and immune dysfunction is present in the progress of heart failure. Dilated cardiomyopathy (DCM) is characteristic of dilated left ventricule, thinning of ventricular wall and declined systolic function, a major cause of chronic heart failure. Nowadays it is believed that the cardiac remodeling is involved in the pathophysiologic process of heart failure.Changes in energy metabolism are often found in the progress of heart failure, directly or indirectly promoting the development of myocardial remodeling (so called "metabolic reconstruction"). During CHF the emery metabolic mode of myocardium converted from using fatty acid (FA) as prior substrate into giving priority to glucose as energy source, inducing the endogenous FA accumulation and decreased energy productivity. L-carnitine is capable of transferring the surplus endogenous FA into mitochondria and reserve FA oxidation in the myocardium of HF, which might improve myocardial energy metabolism and alleviate cardiac deterioration. Transforming growth factor-β1, with wider distribution and stronger activity, is one of the major fibrosis-promoting factors in myocardium. It has been shown by previous studies that L-carnitine is able to inhibit the expression of TGF-β1in myocardial infarct rats, but the relevant clinical study is still lacking. ObjectiveTo observe the changes of heart function and plasma TGF-β1level in patients with DCM and investigate the role of1-carnitine in ventricular remodeling.Methods60patients diagnosed of DCM according to the criteria of WHO/ISFC were randomly divided into1-carnitine group (n=30) and control group (n=30). Both groups were given conventional therapies for heart failure for2weeks, and meanwhile the treatment group also received L-carnitine by intravenous drip,2g each time, once a day. Before and after the treatment, the assessments of the United States New York Heart Association (NYHA), Heart function grade,6minutes’ walking test(6MWT),left ventricular end-diastolic diameter (LVEDD), left ventricular ejection fraction (LVEF), left ventricular end-diastolic volume (EDV), left ventricular systolic volume (ESV), left ventricular short axis shortening rate (FS), the plasma level of TGF-β1, N end B-type natriuretic peptide (NT-proBNP), hypersensitive C-reactive protein (HsCRP) levels, and24hours Holter monitor electrocardiogram for indexes of ventricular arrhythmias were performed. SPSS17.0statistics software was employed in statistical analysis, a P-value of less than0.05was considered statistically significant.Result1. After2weeks, the NYHA classification was generally improved by1or2grades, and the6-minute walking distance was also significantly prolonged, accompanied by increased exercise tolerance.2. Compared with the control group, LVEF, EDV, ESV were greatly improved in L-carnitine group, and the difference was statistically significant (P<0.05); The LVEDD and FS in L-carnitine group were also improved to some extent, but the difference was of no statistical significance.3. The plasma TGF-β1, NT-proBNP and HsCRP in L-carnitine treated group significantly decreased compared with that in control group (P<0.05). 4. After2weekstreatment, the occurrence of malignant arrhythmia in L-carnitine group decreased, but was not statistically different when compared with the control group (3%vs13%, P>0.05).Conclusion1. L-carnitine may improve the heart function and exercise tolerance in patients with dilated cardiomyopathy.2. L-carnitine can be used for auxiliary treatment in patients with dilated cardiomyopathy through improving myocardial remodeling,.3.L-carnitine may ameliorate arrhythmia in DCM patients, which is probably through inhibiting TGF-β1expression and then attenuate myocardial fibrosis. |
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