Atrial and vascular oxidative stress in patients with heart failure.

Heart failure is characterized by a great number of metabolic and histological defects, however, previous studies did not provide strong evidence of a correlation between the antioxidant status of myocardial tissue itself and cardiac function. The goal of our study was to assess, in patients with heart failure consecutive to dilated cardiomyopathy (DCM), alterations in norepinephrine (NE), lipid peroxidation (malonedialdehyde: MDA) and iron levels in different parts of the myocardium and aorta, in relation to functional parameters. Biopsied heart samples were obtained from 12 DCM patients and from 4 brain-dead organ donors (Controls). The left ventricular ejection fraction (LVEF) was reduced to 19.1±2.6% in DCM. For all patients, the distribution of NE in the atria, ventricles and vessels was different, but NE content in control hearts was systematically higher than in cardiomyopathy patients. MDA levels tended to be higher in the different samples from the DCM group in comparison with the values obtained in the C group; the values were significantly decreased (p<0.05) in endocardium and the aortic samples. In the right atrium there was a significant correlation between NE content and LVEF and between MDA and iron concentrations. These findings could give further insights into the relationship between iron metabolism disturbances and the severity of cardiovascular diseases.

Regional heterogeneity of decreased myocardial norepinephrine and increased lipid peroxidation levels in patients with end-stage failing heart secondary to dilated or ischemic cardiomyopathy.

BACKGROUND: Regional alterations in norepinephrine (NE) and lipid peroxidation in the myocardium of patients with heart failure is not well known. This study was designed to investigate regional myocardial NE levels and lipid peroxidation index and their relationships with the functional parameters in two pathologic conditions: dilated cardiomyopathy (DCM) and ischemic cardiomyopathy (ICM). METHODS: Biopsied heart samples were obtained from 13 DCM and 10 ICM patients (orthotopic cardiac transplantation). Tissue NE was assayed by high-pressure liquid chromatography with electrochemical detection. Tissue lipid peroxidation (malondialdehyde, MDA) was evaluated by the thiobarbituric acid (TBA) reaction. RESULTS: Non-failing hearts (controls, n = 4) were included in this study for comparison. Left ventricular dysfunction was present at rest with a mean left ventricular ejection fraction (LVEF) of 19.1 +/- 2.6% for DCM patients and 17.4 +/- 2.0% for ICM patients. The amount of NE in control hearts was significantly lower (p < 0.05) than in DCM or ICM hearts. For all patients, there were several differences in distribution of NE among the sub-divisions of the atria and ventricles studied. NE content was significantly higher in the right atria than in the left atria or ventricles. A significant correlation between LVEF and NE concentrations was observed in the left septum of ICM and DCM patients and in the left ventricle of the ICM group. In DCM and ICM patients, some parts of the left ventricle showed higher levels of lipid peroxides compared with controls. MDA levels in patients with DCM varied little from one region to another, whereas in ICM patients there was considerable variation. CONCLUSIONS: This study is the first demonstration of a correlation between the values of pre-operative LVEF and cardiac NE concentrations in specific parts of the myocardium. This effect could not be generalized to the entire heart. The pattern of myocardial MDA distribution did not follow that of the NE distribution.