No abstract

OBJECTIVE:Chagas' disease has spread throughout Latin America because of the high rate of migration among these countries. Approximately 30% of Chagas' patients will develop cardiomyopathy, and 10% of these will develop severe cardiac damage leading to heart failure. Beta-blockade improves symptoms and survival in heart failure patients; however, its efficacy has not been well established in Chagas' disease. We evaluated the role of carvedilol in cardiac remodeling and mortality in a Chagas' cardiomyopathy animal model.METHODS:We studied Trypanosoma cruzi infection in 55 Syrian hamsters that were divided into three groups: control (15), infected (20), and infected + carvedilol (20). Animals underwent echocardiography, electrocardiography, and morphometry for collagen evaluation in ventricles stained with picrosirius red.RESULTS:The left ventricular diastolic diameter did not change between groups, although it was slightly larger in infected groups, as was left ventricular systolic diameter. Fractional shortening also did not change between groups, although it was slightly lower in infected groups. Collagen accumulation in the interstitial myocardial space was significantly higher in infected groups and was not attenuated by carvedilol. The same response was observed in the perivascular space. The survival curve showed significantly better survival in the control group compared with the infected groups; but no benefit of carvedilol was observed during the study. However, in the acute phase (up to 100 days of infection), carvedilol did reduce mortality.CONCLUSION:Carvedilol did not attenuate cardiac remodeling or mortality in this model of Chagas' cardiomyopathy. The treatment did improve survival in the acute phase of the disease.

Objective: To find out whether there is a correlation between a myocardial structural marker and the overlife rate of patients with dilated cardiomyopathy. Methods:Using endomyocardial biopsy and 2D-echocardiogram, we studied nine patients with no changes in myocardial structure (control) and 45 patients with severe dilated cardiomyopathy of idiopathic etiology (IDCM) and of Chagasic etiology (CDCM). We analyzed the correlation between the quantity of interstitial myocardial collagen (ICVF) and the overlife rates of these patients. We also evaluated the difference in ICVF between these groups and whether fibrosis interfered on the geometry and function of the myocardium. Results:We observed that ICVF was 15 times higher in cardiomyopathy patients than in the control group, but there was no difference in ICVF between CDCM and IDCM (*p < 0.001) patients. There was no correlation between ICVF and the overlife rate in cardiomyopathy patients (IDCM p = 0.249, and CDCM p = 0.587). We observed a significant correlation between ICVF and left ventricular ejection fraction (LVEF) only for IDCM. There was no correlation between ICVF and left ventricular diastolic diameter in either etiology. Conclusion:There was no difference in myocardial fibrosis between patients with CDCM or IDCM, and there was no correlation between fibrosis and the prognosis either for IDCM or CDCM. There was a correlation between myocardial fibrosis and LVEF only for IDCM.Key words: Collagen, myocardium, prognosis, dilated cardiomyopathy. D i l a t e d c a r d i o m y o p a t h y r e p r e s e n t s 8 7 % o f cardiomyopathies. Idiopathic dilated cardiomyopathy (IDCM) has an indeterminate origin, once secondary causes are ruled out. In the United States, its incidence is estimated at 5 to 8/100,000 inhabitants in the population in general, which represents one fourth of dilated cardiomyopathies, with a prevalence adjusted for age of 36/100,000 of the population in general, a 5-year overlife rate of 25% to 65%, depending on the stage of the disease, and annual mortality of 10,000 cases [1][2][3][4] . Chagasic dilated cardiomyopathy (CDCM) is considered an inflammatory disease secondary to infection by a parasite, Trypanosoma cruzi. Data of the World Health Organization show that approximately ninety million people are exposed to the risk of infection by Trypanosoma cruzi, in that the incidence of such infection in 1995 was of 120,000 new casesIrrespective of the etiology, there is accumulation of collagen in the interstitium and in the perivascular space of the myocardium. Myocardial collagen is known to perform important functions which directly affect the heart's morphology, geometry and functional performance. Shirey et al Clinical, functional and biochemical markers of prognosis in dilated cardiomyopathies and heart failure (HF) are well defined. However, a histological marker has not been established yet. It is therefore important to assess the role of interstitial myocardial collagen as a structural prognostic marker in dilated cardiomyopathies. ...

No abstract