Remodelamento cardíaco: análise seriada e índices de detecção precoce de disfunção ventricular

FUNDAMENTO: A estenose aórtica supravalvar (EAo) é utilizada para o estudo da remodelação cardíaca (RC) por sobrecarga pressórica. Nesse modelo, não estão claramente estabelecidos o comportamento da RC desde a fase inicial, nem os melhores parâmetros para a identificação da disfunção ventricular. OBJETIVOS: 1) Caracterizar, precoce e evolutivamente, as modificações morfofuncionais durante a RC em ratos com EAo e 2) identificar o índice mais sensível para detecção do momento do aparecimento da disfunção diastólica e sistólica do ventrículo esquerdo (VE). MÉTODOS: Ratos Wistar foram divididos em dois grupos - controle (GC, n=13) e EAo (GEAo, n=24) - e estudados nas 3ª, 6ª, 12ª e 18ª semanas pós-cirurgia. Os corações foram analisados por meio de ecocardiograma (ECO). RESULTADOS: Ao final do experimento, as relações do VE, do ventrículo direito e dos átrios com o peso corporal final foram aumentadas no GEAo. O ECO mostrou que o átrio esquerdo sofreu uma remodelação significativa a partir da 6ª semana. No GEAo, a porcentagem de encurtamento endocárdico apresentou queda significativa a partir da 12ª semana e a porcentagem de encurtamento mesocárdico, na 18ª semana. A relação onda E e onda A (E/A) foi superior no GC em comparação ao GEAo em todos os momentos analisados. CONCLUSÕES: O ventrículo esquerdo dos ratos com EAo, durante o processo de remodelação, apresentou hipertrofia concêntrica, disfunção diastólica precoce e melhoria da função sistólica, com posterior deterioração do desempenho. Além disso, constatou-se que os índices ecocardiográficos mais sensíveis para a detecção da disfunção diastólica e sistólica são, respectivamente, a relação E/A e a porcentagem de encurtamento endocárdico.

Aspectos clínico-laboratoriais da infecção natural por Trypanosoma cruzi em cães de Mato Grosso do Sul

A doença de Chagas causada pelo T. cruzi é transmitida, principalmente, por insetos vetores e está distribuída na Argentina, no Chile, na Venezuela e no Brasil. O cão, além de ser um importante reservatório, também é vítima da doença e a única espécie capaz de desenvolver manifestações clínicas iguais a do homem. O presente trabalho teve como objetivo descrever as alterações clínicas encontradas em quatro cães infectados naturalmente pelo T. cruzi e alertar para a possibilidade de que a ocorrência dessa enfermidade em cães de Mato Grosso do Sul possa estar sendo subestimada. Os animais foram selecionados a partir de exames sorológicos de reação de imunofluorescência indireta (RIFI), ensaio imunossorvente ligado à enzima (ELISA) e immunoblotting com antígeno secretado e excretado da forma tripomastigota do T. cruzi (TESA-blot) e submetidos a xenodiagnóstico, exame físico, radiografia torácica, eletrocardiografia, ecocardiografia e bioquímica sérica. As alterações encontradas foram aumento de ventrículo direito, presença de arritmias do tipo bloqueio átrio ventricular, sinus arrest e bloqueio de ramo direito, além de disfunção sistólica e diastólica. Três animais apresentaram hiperproteinemia e as dosagens das enzimas CK e CK-MB revelaram valores indicativos de uma miocardite ativa. Esses são os primeiros casos descritos de cães com evidências consistentes de infecção natural pelo T. cruzi em Mato Grosso do Sul e ressalta-se o alerta aos médicos veterinários para a importância clínica e o papel dessa espécie como reservatório da doença.

Fístula arteriovenosa pulmonar maciça. Causa rara, potencialmente curável de hipóxia neonatal.

The case of a six-day-old neonate admitted in an emergency situation because of dyspnea and increasing cyanosis is reported. Despite abnormal opacification on the chest X-ray and left ventricular overload on the electrocardiogram and echocardiogram, features compatible with the disease, the diagnosis of massive pulmonary arteriovenous fistula affecting the whole left superior lobe, was made possible only after necroscopic examination.

Food restriction-induced myocardial dysfunction demonstrated by the combination of in vivo and in vitro studies

The aim of this study was to test the hypothesis that protein-calorie undernutrition decreases myocardial contractility jeopardizing ventricular function, and that ventricular dysfunction can be detected noninvasively. Five-month-old male Wistar-Kyoto rats were fed with regular rat chow ad libitum for 90 days (Control group, n = 14). A second group of rats received 50% of the amount of diet consumed by de control group (Food restricted group, n = 14). Global LV systolic function was evaluated in vivo, noninvasively, by transthoracic echocardiogram. After echocardiographic study, myocardial contractility was assessed in vitro in the isovolumetrically beating isolated heart in eight animals from each group (Langendorff preparation). The in vivo LV fractional shortening showed that food restriction depressed LV systolic function (p < 0.05). Myocardial contractility was impaired as assessed by the maximal rate of rise of LV pressure (+dP/dt), and developed pressure at diastolic pressure of 25 mmHg (p < 0.05). Furthermore, food restriction induced eccentric ventricular remodeling, and reduced myocardial elasticity and LV compliance (p < 0.05). In conclusion, food restriction causes systolic dysfunction probably due to myocardial contractility impairment and reduction of myocardial elasticity. © 2002 Elsevier B.V. All rights reserved.

Edema agudo pulmonar associado à obstrução das vias aéreas. Relato de caso

BAKGROUND AND OBJECTIVES: Negative pressure pulmonary edema has been defined as non-cardiogenic edema, with transudation of fluid to the interstitial space of the lungs due to an increase in negative intrathoracic pressure secondary to obstruction of the upper airways. This is the case of a healthy patient who underwent general anesthesia and developed acute pulmonary edema after extubation. CASE REPORT: A 23-year old female patient, physical status ASA II, underwent gynecologic videolaparoscopy under general anesthesia. The procedure lasted 3 hours without intercurrence. After extubation the patient developed laryngeal spasm and reduction in oxygen saturation. The patient improved after placement of an oral cannula and administration of oxygen under positive pressure with a face mask. Once the patient was stable she was transferred to the recovery room where, shortly after her arrival, she developed acute pulmonary edema with elimination of bloody serous secretion. Treatment consisted of elevation of the head, administration of oxygen via a face mask, furosemide and fluid restriction. Chest X-ray was compatible with acute pulmonary edema and normal cardiac area. Electrocardiogram (ECG), echocardiogram and cardiac enzymes were normal. The condition of the patient improved and she was discharged from the hospital the following day, asymptomatic. CONCLUSIONS: Acute pulmonary edema associated with obstruction of the upper airways can aggravate surgical procedures with low morbidity, affecting mainly young patients. Early treatment should be instituted because it has a fast evolution and, in most cases, resolves without lasting damages. © Sociedade Brasileira de Anestesiologia, 2008.

Relevãncia do padrão de remodelamento ventricular no modelo de infarto do miocárdio em ratos

Background: The relevance of the remodeling pattern in the model of infarcted rats is not known. Objective: To analyze the presence of different patterns of remodeling in this model and its functional implications. Methods: Infarcted rats (n=47) have been divided according to the geometry pattern, analyzed by echocardiogram: normal (normal mass index and normal relative thickness), concentric remodeling (normal mass index and increased relative thickness), concentric hypertrophy (increased mass index and increased relative thickness) and eccentric hypertrophy (increased mass index and normal relative thickness). Data are median and interquartile range. Results: Infarcted rats showed only two of the four geometric patterns: normal pattern (15%) and eccentric hypertrophy - EH (85%). Groups of normal pattern and EH showed no differences in the values of fractional area change (Normal = 32.1-28.8 to 50.7; EH = 31.3-26.5 to 36.7; p = 0.343). Out of the infarcted animals, 34 (74%) had systolic dysfunction, detected by fractional area change. Considering these two geometry patterns, 77% of animals with eccentric hypertrophy and 57% with normal geometry presented systolic dysfunction (p=0.355). The relative wall thickness, the geometric patterns and the body mass index were not predictors of ventricular dysfunction (p>0.05). On the other hand, infarct size was a predictive factor for ventricular dysfunction in univariate analysis (p<0.001) and multivariate analysis (p = 0.004). Conclusion: Rats that underwent coronary occlusion showed two different patterns of remodeling, which do not constitute a predictor of ventricular dysfunction.

Tachycardia-induced cardiomyopathy

Tachycardia-induced cardiomyopathy (TIC) is an important cause of heart failure as it is potentially reversible after ventricular rate control. A 66-year-old hypertensive woman presented with a 15-day history of tachycardia, dyspnoea and oedema. ECG revealed atrial fibrillation with ventricular frequency of 130 beats per minute (bpm). Echocardiogram showed dilated left ventricle (LV) with 0.39 ejection fraction. Angiography revealed non-obstructed coronary arteries. Heart rate and cardiac failure were controlled with amiodarone, digoxine, captopril, metoprolol and furosemide. During follow-up, despite drug dose optimisation, the patient kept complaining of tachycardia and dyspnoea with a ventricular rate between 108 and 120 bpm. Medical staff suspected she was not taking her medicines properly. Two months later, the patient was asymptomatic and had converted to sinus rhythm (heart rate of 76 bpm). Echocardiogram showed normal LV size and function. Patient 's diagnosis was TIC. Although rare, TIC should be considered in all cases of systolic dysfunction associated with tachyarrhythmia. Copyright 2012 BMJ Publishing Group. All rights reserved.

Cardiac remodeling induced by 13-cis retinoic acid treatment in acne patients

Background: Currently, 13-cis-retinoic acid (13-cis-RA) is the most effective therapy for acne. Isotretinoin, a first-generation synthetic 13-cis-RA compound, is associated with numerous adverse effects. To investigate the cardiac effects of 13-cis-RA, acne patients receiving 13-cis-RA were studied. Methods: Twenty male patients with acne were enrolled in the study. Patients were treated with a dose of 0.5 mg/kg/d of isotretinoin. All participants were assessed prior to treatment and after 10 weeks of therapy with Doppler-echocardiogram. Results: Patients showed reductions in right atrium vertical diameter, left atrium longitudinal diameter, left atrium volume and left ventricular diastolic diameter over the course of treatment. Significant increases in interventricular septum diastolic thickness, posterior wall diastolic thickness, relative wall relative thickness and left ventricle (LV) mass were observed. The LV mass index showed an increase in ventricular mass and a decrease in the cavity size. Examining LV systolic function, a decrease was observed for the cardiac index. Conclusion: In this study, 10 weeks of 13-cis-RA therapy at a dose of 0.5 mg/kg/d was found to promote concentric-type heart remodeling due to the occurrence of two associated events: heart hypertrophy and hypovolemia. © 2011 Elsevier B.V. All rights reserved.

Heart failure-induced skeletal myopathy in spontaneously hypertensive rats

Background: Although skeletal muscle atrophy and changes in myosin heavy chain (MyHC) isoforms have often been observed during heart failure, their pathophysiological mechanisms are not completely defined. In this study we tested the hypothesis that skeletal muscle phenotype changes are related to myogenic regulatory factors and myostatin/follistatin expression in spontaneously hypertensive rats (SHR) with heart failure. Methods: After developing tachypnea, SHR were subjected to transthoracic echocardiogram. Pathological evidence of heart failure was assessed during euthanasia. Age-matched Wistar-Kyoto (WKY) rats were used as controls. Soleus muscle morphometry was analyzed in histological sections, and MyHC isoforms evaluated by electrophoresis. Protein levels were assessed by Western blotting. Statistical analysis: Student's t test and Pearson correlation. Results: All SHR presented right ventricular hypertrophy and seven had pleuropericardial effusion. Echocardiographic evaluation showed dilation in the left chambers and left ventricular hypertrophy with systolic and diastolic dysfunction in SHR. Soleus weight and fiber cross sectional areas were lower (WKY 3615±412; SHR 2035±224 μm2; P < 0.001), and collagen fractional volume was higher in SHR. The relative amount of type I MyHC isoform was increased in SHR. Myogenin, myostatin, and follistatin expression was lower and MRF4 levels higher in SHR. Myogenin and follistatin expression positively correlated with fiber cross sectional areas and MRF4 levels positively correlated with I MyHC isoform. Conclusion: Reduced myogenin and follistatin expression seems to participate in muscle atrophy while increased MRF4 protein levels can modulate myosin heavy chain isoform shift in skeletal muscle of spontaneously hypertensive rats with heart failure. © 2012 Elsevier B.V.

Carotid artery atherosclerotic profile as a predictor of the aorta atherosclerotic profile in patients with cerebrovascular events

Background: It is well known that the presence of atheroma of the thoracic aorta is a risk factor for cerebrovascular events. We sought to evaluate whether the presence and the morphology of atherosclerotic plaque in the carotid artery detected by duplex ultrasonography is associated with disease in the proximal aorta visualized by transesophageal echocardiogram in patients with a cerebrovascular event. Methods: We carried out a cross-sectional prospective study including 147 consecutive patients with prior stroke or transient ischemic attack (TIA). Neurological evaluations were performed by an expert neurologist using clinical and tomographic diagnostic criteria including the definition of etiology and whether the patient suffered from stroke or TIA. Transthoracic and transesophageal echocardiograms and carotid artery duplex ultrasonography were performed by the same examiner. Patients with and without plaque in the carotid artery were compared using Student's t test or the χ2 test. Regression analysis was used to determine whether the presence of plaque in the carotid artery was predictive of the presence of plaque in the proximal aorta and to analyze the relationship between the echogenicity of carotid and aortic plaques. The significance level was set at p < 0.05. Results: All 147 patients (95 men) were included in the analysis. Patients' ages ranged from 23 to 85 years (65 ± 12.4 years). Most of the patients (58.5%) were Caucasian, while 41.5% were African-Brazilian. Arterial hypertension, diabetes and tobacco use were more frequent among patients with atherosclerotic plaque in the aorta. A normal carotid intima-media thickness halved the risk of atherosclerotic plaque in the aorta [odds ratio (OR) 0.46, 95% confidence interval (CI) 0.23-0.91; p = 0.026]. The presence of carotid plaque increased the risk of aortic plaque by 70-fold (OR 73.2, 95% CI 25.6-2,018.6; p < 0.001) in univariate analysis. The absence of atherosclerotic plaque in the carotid artery reduced the risk of plaque in the aorta to almost 0 (OR 0.014, 95% CI 0.004-0.041; p < 0.001). Considering the 86 patients with both aortic and carotid plaques, the presence of hypoechoic plaque in the carotid artery was a predictor of hypoechoic plaque in the aorta (OR 10.1, 95% CI 3.3-31.2; p < 0.001). Conclusions: The carotid artery atherosclerotic profile defined by ultrasonography is a strong predictor of the atherosclerotic profile of the proximal aorta. This should be taken into consideration before referring patients with acute cerebrovascular events for transesophageal echocardiogram. © 2013 S. Karger AG, Basel.

Influência do exercício físico na expressão da miostatina e folistatina no músculo sóleo de ratos com insuficiência cardíaca crônica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeito do bloqueio da aldosterona na remodelação cardíaca de ratos espontaneamente hipertensos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Expressão dos fatores de regulação miogênica, composição das miosinas e trofismos no músculo esquelético periférico de ratos com insuficiência cardíaca crônica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Tolerância ao esforço físico e função cardíaca em diferentes períodos pós-indução de estenose aórtica em ratos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação cardíaca de cães com degeneração valvar mixomatosa durante o emprego de enalapril, losartana, furosemida e suas combinações

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)