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Background: A global function index (GFI) derived from tissue Doppler imaging (TDI) has been proposed to improve the diagnosis of hypertrophic cardiomyopathy (HCM). We aimed to evaluate the usefulness of this index in a large selected HCM population. Methods: GFI =[E/Ea]/Sa, was calculated at mitral annulus lateral and septal borders in 164 HCM patients and in 40 healthy volunteers. Group comparisons and correlations between GFI and other variables were performed. Results: Of the 164 patients, 69 (42%) had a peak gradient >30 mmHg in the left ventricle outflow tract (LVOT). GFI (lateral or septal) was not normally distributed. There were differences among controls, obstructive HCM, and nonobstructive HCM (P < 0.0001), but significant overlap of GFI values were observed between groups. GFI was correlated to septal thickness (r = 0.44; P < 0.0001), left atrial diameter (r = 0.52; P < 0.0001), and LVOT gradient (r = 0.58; P < 0.0001). Conclusion: In a selected HCM population, GFI was limited by its asymmetrical distribution and significant overlap of values between groups. Further studies are necessary to verify the reliability of GFI in the clinical practice and its position among other tissue Doppler indices. [ABSTRACT FROM AUTHOR]

The association of anomalous right coronary artery originating from the pulmonary artery and constrictive pericarditis has never been showed in the literature. We present the first case of this unusual association in a patient with right heart failure. After diagnosis, the patient was referred to surgery and underwent phrenic-to-phrenic pericardiectomy; graft implant of right internal thoracic artery to right coronary artery; and ligation of the anomalous origin of the right coronary artery from the pulmonary artery. Such procedures solved the potential risk of sudden death related to anomalous right coronary artery originating from the pulmonary artery and alleviated the symptoms of heart failure caused by constrictive pericarditis. [ABSTRACT FROM AUTHOR]

Background: Omecamtiv mecarbil improves outcomes in patients with heart failure and reduced ejection fraction (HFrEF). We examined the relationship between baseline troponin levels, change in troponin levels over time and the treatment effect of omecamtiv mecarbil in patients enrolled in the Global Approach to Lowering Adverse Cardiac Outcomes through Improving Contractility in Heart Failure (GALACTIC-HF) trial (NCT02929329)., Methods: GALACTIC-HF was a double-blind, placebo-controlled trial that randomized 8256 patients with symptomatic HFrEF to omecamtiv mecarbil or placebo. High-sensitivity troponin I (cTnI) was measured serially at a core laboratory. We analyzed the relationship between both baseline cTnI and change in cTnI concentrations with clinical outcomes and the treatment effect of omecamtiv mecarbil., Results: Higher baseline cTnI concentrations were associated with a risk of adverse outcomes (hazard ratio for the primary endpoint of time to first HF event or CV death = 1.30; 95% CI 1.28, 1.33; P < 0.001 per doubling of baseline cTnI). Although the incidence of safety outcomes was higher in patients with higher baseline cTnI, there was no difference between treatment groups. Treatment with omecamtiv mecarbil led to a modest increase in cTnI that was related to plasma concentrations of omecamtiv mecarbil, and it peaked at 6 weeks. An increase in troponin from baseline to week 6 was associated with an increased risk of the primary endpoint (P < 0.001), which was similar, regardless of treatment assignment (P value for interaction = 0.2)., Conclusions: In a cohort of patients with HFrEF, baseline cTnI concentrations were strongly associated with adverse clinical outcomes. Although cTnI concentrations were higher in patients treated with omecamtiv mecarbil, we did not find a differential effect of omecamtiv mecarbil on either safety or efficacy based on baseline cTnI status or change in cTnI., Competing Interests: DISCLOSURES GMF has received research grants from NHLBI, American Heart Association, Amgen, Bayer, BMS, Merck, Cytokinetics, and CSL-Behring; he has acted as a consultant to Novartis, Amgen, BMS, Cytokinetics, Medtronic, Cardionomic, Boehringer-Ingelheim, American Regent, Abbott, Astra-Zeneca, Reprieve, Myovant, Sequana, Windtree Therapuetics, and Whiteswell and has served on clinical endpoint committees/data safety monitoring boards for Amgen, Merck, Medtronic, EBR Systems, V-Wave, LivaNova, Siemens, and Rocket Pharma. SDS reports receiving grants (via Brigham and Women's Hospital) from Amgen and Cytokinetics during the conduct of the study; grants (via Brigham and Women's Hospital) from Actelion, Alnylam Pharmaceuticals, Amgen, AstraZeneca, Bellerophon Therapeutics, Bayer, Bristol Myers Squibb, Celladon, Cytokinetics, Eidos Therapeutics, Eli Lilly, Gilead Sciences,GlaxoSmithKline, Ionis Pharmaceuticals, Mesoblast,Myocardium, the National Heart, Lung, and Blood Institute, NeuroTronik, Novartis, Novo Nordisk, Respicardia, Sanofi Pasteur, and Theracos; and consulting fees from Abbott Laboratories, Action Pharma, Akros Pharma, Alnylam Pharmaceuticals, American Regent, Amgen, Arena Pharmaceuticals, AstraZeneca, Bayer, Boehringer Ingelheim, Bristol Myers Squibb, Cardiac Dimensions, Cardior Pharmaceuticals, Cardurion Pharmaceuticals, CellProthera, Corvia Medical, Cytokinetics, Daiichi Sankyo, Dinaqor, Eli Lilly and Company, GlaxoSmithKline, Janssen Pharmaceuticals, Merck & Co, Moderna, Myokardia, Novartis, Quantum Genomics, Roche, Sanofi Pasteur, Sarepta Therapeutics, Tenaya Therapeutics, Theracos, and Tremeau Pharmaceuticals. MM reports receiving personal fees from Amgen and Servier Laboratories during the conduct of the study and personal fees from Abbott Laboratories, Actelion, AstraZeneca, Edwards Lifesciences, LivaNova, Vifor Pharma, and Windtree Therapeutics. JJVM reports receiving travel fees and nonfinancial support (via the University of Glasgow) from Amgen during the conduct of the study; travel fees and nonfinancial support (via the University of Glasgow) from Alnylam Pharmaceuticals, AstraZeneca, Bayer, Bristol Myers Squibb, Cyclerion Therapeutics, Cytokinetics, DalCor Pharmaceuticals, GlaxoSmithKline, Novartis, Pfizer, Servier Laboratories, and Theracos; and personal fees from Abbott Laboratories, Hikma Pharmaceuticals, Servier Laboratories, and Sun Pharmaceutical Industries. RD reports receiving grants from Amgen during the conduct of the study. BC reports receiving grants (via Brigham and Women's Hospital) from Amgen and Cytokinetics during the conduct of the study and consulting fees from Amgen, Boehringer Ingelheim, Corvia Medical, Myokardia, and Novartis. DEL is supported in part by grants from the National Institutes of Health (P50MD017351, R01HL132154), has received research funding or support from Amgen, Astra Zeneca, Janssen, Eli Lilly, and Somalogic, and has acted as consultant to ACI Clinical (Abbott Laboratories), AstraZeneca, Cytokinetics, Duke Clinical Research Institute (CONNECT-HF), Illumina, Janssen, Martin Pharmaceuticals, Ortho Clinical Diagnostics, and Otsuka. HV reports being a national leader of GALACTIC-HF and has received lecture fees and consultation fees from Amgen. RDL reports research grants or contracts from Amgen, Bristol-Myers Squibb, GlaxoSmithKline, Medtronic, Pfizer, Sanofi-Aventis and funding for educational activities or lectures from Pfizer and Daiichi Sankyo and funding for consulting or other services from Bayer, Boehringer Ingelheim, Bristol-Myers Squibb, and Novo Nordisk. S-IM reports being a national leader of GALACTIC-HF and has received lecture and consultation fees from Amgen. TB-S reports being a steering committee member of the Amgen-financed GALACTIC-HF trial, chief investigator and steering committee chair of the Sanofi Pasteur-financed NUDGE-FLU trial; chief investigator and steering committee chair of the Sanofi Pasteur-financed DANFLU-1 trial; steering committee member of LUX-Dx TRENDS Evaluates Diagnostics Sensors in Heart Failure Patients Receiving Boston Scientific's Investigational ICM System trial; is on the advisory boards of Sanofi Pasteur, Amgen and GSK; receives speaker honoraria from Bayer, Novartis, Sanofi Pasteur, and GSK and research grants from GE Healthcare and Sanofi Pasteur. SBH, PHD, SK, and FIM are employees of Cytokinetics. JRT reports receiving grants from Amgen and Cytokinetics, personal fees from Amgen, Cytokinetics and Servier Laboratories, and nonfinancial support from Amgen and Cytokinetics during the conduct of the study; grants from Abbott Laboratories, Bayer, Boerhinger Ingelheim, Bristol Myers Squibb, EBR Systems, LivaNova, Medtronic, Novartis, and Windtree Therapeutics; and personal fees from Amgen, AstraZeneca, Cytokinetics, Merck & Co, and Servier Laboratories. All other authors report no relevant disclosures., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Purpose: To evaluate myocardial T1 mapping and extracellular volume (ECV) parameters in different stages of Chagas cardiomyopathy and determine whether they are predictive of disease severity and prognosis., Materials and Methods: Prospectively enrolled participants (July 2013 to September 2016) underwent cine and late gadolinium enhancement (LGE) cardiac MRI and T1 mapping with a precontrast (native) or postcontrast modified Look-Locker sequence. The native T1 and ECV values were measured among subgroups that were based on disease severity (indeterminate, Chagas cardiomyopathy with preserved ejection fraction [CCpEF], Chagas cardiomyopathy with midrange ejection fraction [CCmrEF], and Chagas cardiomyopathy with reduced ejection fraction [CCrEF]). Cox proportional hazards regression and the Akaike information criterion were used to determine predictors of major cardiovascular events (cardioverter defibrillator implant, heart transplant, or death)., Results: In 107 participants (90 participants with Chagas disease [mean age ± SD, 55 years ± 11; 49 men] and 17 age- and sex-matched control participants), the left ventricular (LV) ejection fraction and the extent of focal and diffuse or interstitial fibrosis were correlated with disease severity. Participants with CCmrEF and participants with CCrEF showed significantly higher global native T1 and ECV values than participants in the indeterminate, CCpEF, and control groups (T1: 1072 msec ± 34 and 1073 msec ± 63 vs 1010 msec ± 41, 1005 msec ± 69, and 999 msec ± 46; ECV: 35.5% ± 3.6 and 35.0% ± 5.4 vs 25.3% ± 3.5, 28.2% ± 4.9, and 25.2% ± 2.2; both P < .001). Remote (LGE-negative areas) native T1 and ECV values were also higher (T1: 1056 msec ± 32 and 1071 msec ± 55 vs 1008 msec ± 41, 989 msec ± 96, and 999 msec ± 46; ECV: 30.2% ± 4.7 and 30.8% ± 7.4 vs 25.1% ± 3.5, 25.1% ± 3.7, and 25.0% ± 2.2; both P < .001). Abnormal remote ECV values (>30%) occurred in 12% of participants in the indeterminate group, which increased with disease severity. Nineteen combined outcomes were observed (median follow-up time: 43 months), and a remote native T1 value greater than 1100 msec was independently predictive of combined outcomes (hazard ratio, 12 [95% CI: 4.1, 34.2]; P < .001)., Conclusion: Myocardial native T1 and ECV values were correlated with Chagas disease severity and may serve as markers of myocardial involvement in Chagas cardiomyopathy that precede LGE and LV dysfunction. Keywords: MRI, Cardiac, Heart, Imaging Sequences, Chagas Cardiomyopathy Supplemental material is available for this article. © RSNA, 2023., Competing Interests: Disclosures of conflicts of interest: R.J.L.M. No relevant relationships. A.N.A. No relevant relationships. T.C.M. No relevant relationships. C.H.N. No relevant relationships. M.I.S. No relevant relationships. M.M.F. No relevant relationships. F.J.A.R. No relevant relationships. F.F. No relevant relationships. B.M.I. No relevant relationships. C.M. No relevant relationships. C.E.R. Secretary-treasurer and board member of the Society for Cardiovascular Magnetic Resonance., (© 2023 by the Radiological Society of North America, Inc.)

Background: The selective cardiac myosin activator omecamtiv mecarbil has been shown to improve cardiac function in patients with heart failure with a reduced ejection fraction. Its effect on cardiovascular outcomes is unknown., Methods: We randomly assigned 8256 patients (inpatients and outpatients) with symptomatic chronic heart failure and an ejection fraction of 35% or less to receive omecamtiv mecarbil (using pharmacokinetic-guided doses of 25 mg, 37.5 mg, or 50 mg twice daily) or placebo, in addition to standard heart-failure therapy. The primary outcome was a composite of a first heart-failure event (hospitalization or urgent visit for heart failure) or death from cardiovascular causes., Results: During a median of 21.8 months, a primary-outcome event occurred in 1523 of 4120 patients (37.0%) in the omecamtiv mecarbil group and in 1607 of 4112 patients (39.1%) in the placebo group (hazard ratio, 0.92; 95% confidence interval [CI], 0.86 to 0.99; P = 0.03). A total of 808 patients (19.6%) and 798 patients (19.4%), respectively, died from cardiovascular causes (hazard ratio, 1.01; 95% CI, 0.92 to 1.11). There was no significant difference between groups in the change from baseline on the Kansas City Cardiomyopathy Questionnaire total symptom score. At week 24, the change from baseline for the median N-terminal pro-B-type natriuretic peptide level was 10% lower in the omecamtiv mecarbil group than in the placebo group; the median cardiac troponin I level was 4 ng per liter higher. The frequency of cardiac ischemic and ventricular arrhythmia events was similar in the two groups., Conclusions: Among patients with heart failure and a reduced ejection, those who received omecamtiv mecarbil had a lower incidence of a composite of a heart-failure event or death from cardiovascular causes than those who received placebo. (Funded by Amgen and others; GALACTIC-HF ClinicalTrials.gov number, NCT02929329; EudraCT number, 2016-002299-28.)., (Copyright © 2020 Massachusetts Medical Society.)

Aims: The safety and efficacy of the novel selective cardiac myosin activator, omecamtiv mecarbil, in patients with heart failure with reduced ejection fraction (HFrEF) is being tested in the Global Approach to Lowering Adverse Cardiac outcomes Through Improving Contractility in Heart Failure (GALACTIC-HF) trial. Here we describe the baseline characteristics of participants in GALACTIC-HF and how these compare with other contemporary trials., Methods and Results: Adults with established HFrEF, New York Heart Association (NYHA) functional class ≥II, ejection fraction ≤35%, elevated natriuretic peptides and either current hospitalization for heart failure or history of hospitalization/emergency department visit for heart failure within a year were randomized to either placebo or omecamtiv mecarbil (pharmacokinetic-guided dosing: 25, 37.5, or 50 mg bid). A total of 8256 patients [male (79%), non-white (22%), mean age 65 years] were enrolled with a mean ejection fraction 27%, ischaemic aetiology in 54%, NYHA class II 53% and III/IV 47%, and median N-terminal pro-B-type natriuretic peptide 1971 pg/mL. Heart failure therapies at baseline were among the most effectively employed in contemporary heart failure trials. GALACTIC-HF randomized patients representative of recent heart failure registries and trials with substantial numbers of patients also having characteristics understudied in previous trials including more from North America (n = 1386), enrolled as inpatients (n = 2084), systolic blood pressure <100 mmHg (n = 1127), estimated glomerular filtration rate <30 mL/min/1.73 m 2 (n = 528), and treated with sacubitril/valsartan at baseline (n = 1594)., Conclusions: GALACTIC-HF enrolled a well-treated, high-risk population from both inpatient and outpatient settings, which will provide a definitive evaluation of the efficacy and safety of this novel therapy, as well as informing its potential future implementation., (© 2020 The Authors. European Journal of Heart Failure published by John Wiley & Sons Ltd on behalf of European Society of Cardiology.)

Background: Clinical trials in heart failure have focused on the improvement in symptoms or decreases in the risk of death and other cardiovascular events. Little is known about the effect of drugs on the risk of clinical deterioration in surviving patients., Methods and Results: We compared the angiotensin-neprilysin inhibitor LCZ696 (400 mg daily) with the angiotensin-converting enzyme inhibitor enalapril (20 mg daily) in 8399 patients with heart failure and reduced ejection fraction in a double-blind trial. The analyses focused on prespecified measures of nonfatal clinical deterioration. In comparison with the enalapril group, fewer LCZ696-treated patients required intensification of medical treatment for heart failure (520 versus 604; hazard ratio, 0.84; 95% confidence interval, 0.74-0.94; P=0.003) or an emergency department visit for worsening heart failure (hazard ratio, 0.66; 95% confidence interval, 0.52-0.85; P=0.001). The patients in the LCZ696 group had 23% fewer hospitalizations for worsening heart failure (851 versus 1079; P<0.001) and were less likely to require intensive care (768 versus 879; 18% rate reduction, P=0.005), to receive intravenous positive inotropic agents (31% risk reduction, P<0.001), and to have implantation of a heart failure device or cardiac transplantation (22% risk reduction, P=0.07). The reduction in heart failure hospitalization with LCZ696 was evident within the first 30 days after randomization. Worsening of symptom scores in surviving patients was consistently more common in the enalapril group. LCZ696 led to an early and sustained reduction in biomarkers of myocardial wall stress and injury (N-terminal pro-B-type natriuretic peptide and troponin) versus enalapril., Conclusions: Angiotensin-neprilysin inhibition prevents the clinical progression of surviving patients with heart failure more effectively than angiotensin-converting enzyme inhibition., Clinical Trial Registration Url: http://www.clinicaltrials.gov. Unique identifier: NCT01035255., (© 2014 American Heart Association, Inc.)

The association of anomalous right coronary artery originating from the pulmonary artery and constrictive pericarditis has never been showed in the literature. We present the first case of this unusual association in a patient with right heart failure. After diagnosis, the patient was referred to surgery and underwent phrenic-to-phrenic pericardiectomy; graft implant of right internal thoracic artery to right coronary artery; and ligation of the anomalous origin of the right coronary artery from the pulmonary artery. Such procedures solved the potential risk of sudden death related to anomalous right coronary artery originating from the pulmonary artery and alleviated the symptoms of heart failure caused by constrictive pericarditis.

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.

Introduction: Chagas' disease is one of the most important causes of dilated cardiomyopathy in South and Central America. It is an inflammatory cardiomyopathy. We wanted to investigate whether it could have the same response to aldosterone antagonism as demonstrated before in other dilated cardiomyopathies., Objective: To evaluate the role of spironolactone in myocardial remodelling in a Chagas cardiomyopathy model., Material and Methods: We studied 60 Sirius Hamsters divided into: control (C) infected (Inf) and Inf plus spironolactone (Infsp, 40 mg/kg/day) groups, for 11 months. Echocardiography with colour doppler was performed. Left ventricular end diastolic diameter (LVEDD), fractional shortening (FS) and corrected isovolumic relaxation time (IRT) were evaluated, as well as interstitial collagen volume fraction (ICVF) and myocardial inflammation., Result: The results demonstrated that survival was improved by use of spironolactone in the chronic phase (p<0.04). Body weight (BW) was C:190 g, Inf:167 g*, Infsp:198 g (*p<0.05, compared to C and Infsp), LVEDD/BW was C:0.31, Inf: 0.35*, Infsp: 0.29 (*p<0.05, compared to C and Infsp), FS was C:38, Inf: 35.5, Infsp: 38 (with no statistical difference) and IRT was C: 23 msec, Inf: 26 msec*, Infsp: 22 msec (p<0.05, compared to C and Infsp). ICVF (%) was attenuated at LV (C: 0.34+/-0.1, Inf: 1.75+/-0.7*, Infsp: 0.95+/-0.2*; *p<0.05, p<0.05)., Conclusion: Spironolactone attenuated the myocardial remodelling in Chagas cardiomyopathy, reduced mortality during the chronic phase and reduced inflammatory infiltration.

Objective: To analyze left ventricular (LV) regional wall motion in patients with endomyocardial fibrosis (EMF)., Methods: The study comprised 88 patients, 59 of the female sex, with a mean age of 39+/-13 years (range, 9 to 65) and with echocardiographic and angiographic evidence of left ventricular EMF. The intensity of fibrous tissue buildup on contrast cineventriculography was classified as mild, moderate, or severe. The overall left ventricular ejection fraction (LVEF) was determined by using the area-length method on ventriculography. The motion was measured in 100 equidistant chords perpendicular to the centerline drawn in the middle of the final diastolic and systolic contours and normalized to cardiac size. Five left ventricular segments were analyzed: A--apical; AL--anterolateral; AB--anterobasal; IA--inferoapical; IB--inferobasal. Abnormality was expressed in units of standard deviation of the mean motion in a normal population of reference, comprised of 103 patients with normal LV according to clinical and electrocardiographic data, and angiographic standards., Results: Mean LVEF was 0.47+/-0.12. Fibrous tissue buildup in the left ventricle was mild in 12 patients, moderate in 40, and severe in 36. The regions with the poorest ventricular wall motion were A (-1.4+/-1.6 standard deviation/chords) and IA (-1.6+/-1.8 standard deviation/chords) compared with that in AB (-0.3+/-1.9 standard deviation/chords), AL (-0.5+/-1.8 standard deviation/chords) and IB (-0.9+/-1.3 standard deviation/chords). No relation was observed between the intensity of fibrous tissue buildup and regional ventricular wall motion., Conclusion: A change in LV regional wall motion exists in EMF, and it is independent of the intensity of fibrous tissue buildup qualitatively assessed. Nonuniform involvement of the LV should be considered when planning surgery for this disease.

Chronic Chagas' disease cardiomyopathy (CCC) is caused by the protozoan Trypanosoma cruzi, and it affects 30% of the 16-18 million people infected in Latin America. A good rodent model that develops a dilated cardiomyopathy closely resembling human CCC after T. cruzi infection is still needed. We compared the cardiomyopathy developed by T. cruzi-infected Syrian hamsters with human Chagas' disease cardiomyopathy using quantitative methods. Female hamsters were infected with 3.5 x 10(4) (G1, n = 10) or 10(5) (G2, n = 10) T. cruzi Y strain blood trypomastigotes. Control animals (C, n = 10) were injected with saline solution. Cardiac function was assessed by echocardiography at 4, 8 and 12 months post-infection. Heart sections were submitted to histopathological/morphometric analysis 12 months post-infection. At this time, ventricular dysfunction and diffuse or multi-focal myocarditis were observed in 91% and 100% of G1 and G2 infected groups, respectively. Median interstitial collagen volumes in groups C, G1 and G2 were 1.2%, 1.9% and 3.9%, respectively, and were significantly higher in group G2 than in group C. Among infected animals, myocarditis showed a positive correlation with interstitial fibrosis. Deaths in the chronic phase (8-12 months post-infection) were more frequent among G2 than G1, and were associated with macroscopic ventricular dilation, severe myocarditis and increased fibrosis values, along with an earlier onset of ventricular dysfunction. The T. cruzi chronically infected Syrian hamster develops a cardiomyopathy which resembles human Chagas' disease cardiomyopathy, and might be an adequate tool to investigate pathogenic mechanisms of this disease and to search for novel therapeutic strategies.

Background: Endothelins are associated with cardiac remodeling. These peptides are the most powerful vasoconstrictor described-whether this remodeling is a direct effect of this hormone or indirect response to a relative ischemia promoted by vasoconstrictor effect. We evaluated the role of endothelin upon myocardial fibrosis despite of its hemodynamic effects and the benefits of its antagonism., Methods and Results: We used 40 Wistar rats: control, sham operated, rats had undergone myocardial infarction (MI) and MI rats treated with SB209670 which is an ET(A)/ET(B) endothelin antagonist. We evaluated tail systolic blood pressure (BP) and left ventricular end diastolic pressure (LVED) before surgery, just after, and at the end of the study. Remodeling was studied based on interstitial collagen and MI size by an image system analysis. BP decreased in MI groups after surgery, but did not differ between treated and untreated animals. LVED had increased levels in MI groups after surgery and did not differ between them. However, ICVF had an increase in MI group but significantly less in MI+SB209670. MI size was similar in both groups., Conclusions: Endothelin may have a pivotal role in the myocardial fibrosis by direct stimulation of collagen accumulation despite of its hemodynamic effects.