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Background: Myocardial norepinephrine is altered in left ventricular impairment. In patients with Chagas' cardiomyopathy (CC), this issue has not been addressed., Objective: To determine the level of myocardial norepinephrine in patients with CC and compare it in patients with coronary artery disease, and to relate myocardial norepinephrine to left ventricular ejection fraction (LVEF)., Methods: We studied 39 patients with CC, divided into group 1: 21 individuals with normal LVEF and group 2: 18 individuals with decreased LVEF. Seventeen patients with coronary artery disease were divided into group 3: 12 individuals with normal LVEF and group 4: 5 individuals with decreased LVEF. Two-dimensional echocardiography was used to measure LVEF. Myocardial norepinephrine was determined by high-performance liquid chromatography., Results: Myocardial norepinephrine in CC with and without ventricular dysfunction was 1.3±1.3 and 6.1±4.2 pg/μg noncollagen protein, respectively (p<0.0001); in coronary artery disease with and without ventricular dysfunction, it was 3.3±3.0 and 9.8±4.2 pg/μg noncollagen protein, respectively (p<0.0001). A positive correlation was found between LVEF and myocardial norepinephrine concentration in the patients with Chagas' cardiomyopathy (p<0.01, r = 0.57) and also in those with coronary artery disease (p<0.01, r=0.69). A significant difference was demonstrated between norepinephrine concentrations in patients with normal LVEF (groups 1 and 3; p = 0.0182), but no difference was found in patients with decreased LVEF (groups 2 and 4; p = 0.1467)., Conclusion: In patients with Chagas' cardiomyopathy and normal global ejection fraction there is an early cardiac denervation, when compared to coronary artery disease patients.

Background: In hypertrophic cardiomyopathy (HCM), interstitial myocardial fibrosis is an important histological modification that has been associated with sudden death and evolution toward myocardial dilation., Objective: To prospectively evaluate the prognostic value of the collagen volume fraction in HCM., Methods: An endomyocardial biopsy of the right ventricle was successfully performed in 21 symptomatic patients with HCM. The myocardial collagen volume fraction (CVF) was determined by histology. The CVF was also determined in fragments of nine normal hearts from subjects deceased from non-cardiac causes. The patients were divided into above-median CVF and below-median CVF groups, and their clinical and echocardiographic characteristics and survival curves were compared., Results: Among the patients, the CVF ranged from 1.86% to 29.9%, median 6.19%; in normal hearts, from 0.13% to 1.46%, median 0.61% (p <0.0001 between HCM and control). There were no significant correlations between CVF and baseline echocardiographic measures. Patients with CVF < or =6.19% and CVF> 6.19% were compared and no baseline differences were observed. However, after an average follow-up period of 110 months, four deaths occurred (two sudden, two due to heart failure) in the group with increased CVF, whereas the patients of the group with lower CVF were all alive at the end of the period (p = 0.02)., Conclusion: For the first time, myocardial fibrosis was prospectively associated with a worse prognosis in patients with HCM. Efforts should be directed to the quantification of myocardial fibrosis in HCM, on the premise that its association with the prognosis can aid in the stratification of risk for defibrillator implantation, and in the prescription of drugs that potentially promote myocardial repair.