Effects of spironolactone in spontaneously hypertensive adult rats subjected to high salt intake

OBJECTIVE: To evaluate the effect of spironolactone on ventricular stiffness in spontaneously hypertensive adult rats subjected to high salt intake. INTRODUCTION: High salt intake leads to cardiac hypertrophy, collagen accumulation and diastolic dysfunction. These effects are partially mediated by cardiac activation of the renin-angiotensin-aldosterone system. METHODS: Male spontaneously hypertensive rats (SHRs, 32 weeks) received drinking water (SHR), a 1% NaCl solution (SHR-Salt), or a 1% NaCl solution with a daily subcutaneous injection of spironolactone (80 mg.kg-1) (SHRSalt- S). Age-matched normotensive Wistar rats were used as a control. Eight weeks later, the animals were anesthetized and catheterized to evaluate left ventricular and arterial blood pressure. After cardiac arrest, a doublelumen catheter was inserted into the left ventricle through the aorta to obtain in situ left ventricular pressurevolume curves. RESULTS: The blood pressures of all the SHR groups were similar to each other but were different from the normotensive controls (Wistar = 109±2; SHR = 118±2; SHR-Salt = 117±2; SHR-Salt-S = 116±2 mmHg; P<0.05). The cardiac hypertrophy observed in the SHR was enhanced by salt overload and abated by spironolactone (Wistar = 2.90±0.06; SHR = 3.44±0.07; SHR-Salt = 3.68±0.07; SHR-Salt-S = 3.46±0.05 mg/g; P<0.05). Myocardial relaxation, as evaluated by left ventricular dP/dt, was impaired by salt overload and improved by spironolactone (Wistar = -3698±92; SHR = -3729±125; SHR-Salt = -3342±80; SHR-Salt-S = -3647±104 mmHg/s; P<0.05). Ventricular stiffness was not altered by salt overload, but spironolactone treatment reduced the ventricular stiffness to levels observed in the normotensive controls (Wistar = 1.40±0.04; SHR = 1.60±0.05; SHR-Salt = 1.67±0.12; SHR-Salt- S = 1.45±0.03 mmHg/ml; P<0.05). CONCLUSION: Spironolactone reduces left ventricular hypertrophy secondary to high salt intake and ventricular stiffness in adult SHRs

Relationship between left atrial volume and diastolic dysfunction in 500 Brazilian patients

BACKGROUND: Left atrial volume index (LAVI) increase has been associated to left ventricle (LV) diastolic dysfunction (DD), a marker of cardiovascular events (atrial fibrillation, stroke, heart failure, death). OBJECTIVE: To evaluate the relationship between LAVI and diferente grades od DD in Brazilian patients submitted to echocardiogram, studying LAVI increase determinants in this sample. METHODS: We have selected 500 outpatients submitted to echocardiography, after excluding arrhythmia, valvar or congenital cardiopathy, permanent pacemaker or inadequate ecocardiographic window. LAVI was obtained according to Simpson's method. DD was classified according to current guidelines. The clinical and echocardiographic variables were submitted to linear regression multivariate analysis. RESULTS: Mean age was 52 ± 15 years old, 53% were male, 55% had arterial hypertension, 9% had coronary artery disease, 8% were diabetic, 24% were obese, 47% had LV hypertrophy. The mean ejection fraction of the left ventricle was 69.6 ± 7,2%. The prevalence of DD in this sample was 33.8% (grade I: 66%, grade II: 29% e grade III: 5%). LAVI increased progressively according to DD grade: 21 ± 4 mL/m² (absent), 26 ± 7 mL/m² (grade I), 33 ± 5 mL/m² (grade II), 50 ± 5 mL/m2 (grade III) (p < 0,001). In this sample, LAVI increase independent predictors were age, left ventricular mass, relative wall thickness, LV ejection fraction and E/e' ratio. CONCLUSION: DD contributes to left atrial remodeling. LAVI increases as an expression of DD severity and is independently associated to age, left ventricle hypertrophy, systolic dysfunction and increased LV filling pressures.FUNDAMENTO: O aumento do Volume do Átrio Esquerdo Indexado (VAEi) tem sido associado à Disfunção Diastólica (DD) do Ventrículo Esquerdo (VE), considerado marcador de eventos cardiovasculares (fibrilação atrial, acidente vascular cerebral, insuficiência cardíaca, e óbito). OBJETIVO: Avaliar a relação entre VAEi e diferentes graus de DD em pacientes brasileiros submetidos ao ecocardiograma, estudando os determinantes do aumento do VAEi nesta amostra. MÉTODOS: Selecionamos 500 pacientes ambulatoriais submetidos a ecocardiografia, após exclusão de arritmia, cardiopatia valvar ou congênita, marca-passo permanente ou janela ecocardiográfica inadequada. O VAEi foi obtido pelo método de Simpson; classificou-se a DD segundo diretrizes atuais. Variáveis clínicas e ecocardiográficas foram submetidas a análise multivariada de regressão linear. RESULTADOS: A idade média foi de 52 ± 15 anos, 53% do sexo masculino, 55% hipertensos, 9% coronariopatas, 8% diabéticos, 24% obesos, 47% com hipertrofia VE, fração de ejeção média do VE: 69,6 ± 7,2%. A prevalência de DD na amostra foi de 33,8% (grau I: 66%, grau II: 29% e grau III: 5%). Houve aumento progressivo das dimensões do VAEi conforme o grau de DD: 21 ± 4 mL/m² (ausente), 26 ± 7 mL/m² (grau I), 33 ± 5 mL/m² (grau II), 50 ± 5 mL/m2 (grau III) (p < 0,001). Os preditores independentes de aumento do VAEi nesta amostra foram idade, massa ventricular esquerda, espessura relativa de parede, fração de ejeção do VE e relação E/e'. CONCLUSÃO: A DD contribui para o remodelamento atrial esquerdo. O aumento do VAEi expressa a gravidade da DD e está associado de forma independente com idade, hipertrofia ventricular esquerda, disfunção sistólica e aumento das pressões de enchimento do VE.Universidade Federal de São Paulo (UNIFESP), Escola Paulista de Medicina (EPM)Medcenter CardiologiaUniversidade Federal do Espirito SantoUNIFESP, EPMSciEL

Exercise training prior to myocardial infarction attenuates cardiac deterioration and cardiomyocyte dysfunction in rats

OBJECTIVES: The present study was performed to investigate 1) whether aerobic exercise training prior to myocardial infarction would prevent cardiac dysfunction and structural deterioration and 2) whether the potential cardiac benefits of aerobic exercise training would be associated with preserved morphological and contractile properties of cardiomyocytes in post-infarct remodeled myocardium. METHODS: Male Wistar rats underwent an aerobic exercise training protocol for eight weeks. The rats were then assigned to sham surgery (SHAM), sedentary lifestyle and myocardial infarction or exercise training and myocardial infarction groups and were evaluated 15 days after the surgery. Left ventricular tissue was analyzed histologically, and the contractile function of isolated myocytes was measured. Student's t-test was used to analyze infarct size and ventricular wall thickness, and the other parameters were analyzed by the Kruskal-Wallis test followed by Dunn's test or a one-way analysis of variance followed by Tukey's test (

Estudo de validação das equações de Tanaka e de Kawasaki para estimar a excreção diária de sódio através da coleta da urina casual

RESUMO: Objetivo: Validar as fórmulas de Tanaka e Kawasaki para cálculo do consumo de sal pela relação sódio/creatinina na urina casual. Métodos: Foram estudados 272 adultos (20 - 69 anos, 52,6% de mulheres) com coleta urinária de 24 h e duas coletas casuais no mesmo dia (em jejum - casual 1 - e fora do jejum - casual 2). Antropometria, pressão arterial e coleta de sangue foram obtidos no mesmo dia. A concordância entre o consumo de sal estimado pela urina de 24 h e pela urina casual foi feita por Pearson (r) e Bland & Altman. Resultados: O consumo médio de sal medido pela urina de 24 h foi de 10,4 ± 5,3 g/dia. A correlação entre a excreção de sódio na urina de 24 h e a estimada pela urina casual 1 ou 2, respectivamente, foi apenas moderada, tanto por Tanaka (r = 0,51 e r = 0,55; p < 0,001) como por Kawasaki (r = 0,52 e r = 0,54; p < 0,001). Observa-se subestimação crescente dos valores estimados em relação ao medido com o aumento do consumo de sal pela fórmula de Tanaka e, ao contrário, superestimação ao usar a fórmula de Kawasaki. As fórmulas estimam adequadamente o consumo diário de sal (diferença entre sal medido e estimado de, no máximo, 1 g/dia) somente com consumo entre 9 - 12 g/dia (Tanaka) e 12 - 18 g/dia (Kawasaki). Conclusão: A coleta de urina casual estima adequadamente o consumo de sal apenas nos indivíduos próximos à média populacional