Marcelo Perim Baldo

Remodeling in the ischemic heart: the stepwise progression for heart

Coronary artery disease is the leading cause of death in the developed world and in developing countries. Acute mortality from acute myocardial infarction (MI) has decreased in the last decades. However, the incidence of heart failure (HF) in patients with healed infarcted areas is increasing. Therefore, HF prevention is a major challenge to the health system in order to reduce healthcare costs and to provide a better quality of life. Animal models of ischemia and infarction have been essential in providing precise information regarding cardiac remodeling. Several of these changes are maladaptive, and they progressively lead to ventricular dilatation and predispose to the development of arrhythmias, HF and death. These events depend on cell death due to necrosis and apoptosis and on activation of the inflammatory response soon after MI. Systemic and local neurohumoral activation has also been associated with maladaptive cardiac remodeling, predisposing to HF. In this review, we provide a timely description of the cardiovascular alterations that occur after MI at the cellular, neurohumoral and electrical level and discuss the repercussions of these alterations on electrical, mechanical and structural dysfunction of the heart. We also identify several areas where insufficient knowledge limits the adoption of better strategies to prevent HF development in chronically infarcted individuals.

Associação entre a razão cintura-estatura e hipertensão e síndrome metabólica: estudo de base populacional

BACKGROUND Hypertension and metabolic syndrome are cardiovascular risk factors associated with increased adiposity. In a previous study, waist-to-stature ratio (WSR) was identified as the best obesity index associated with left ventricular hypertrophy. OBJECTIVE In this study we compared the ability of this index to identify hypertension and metabolic syndrome with other obesity indexes (body mass index--BMI; waist circumference--WC; and waist-to-hip ratio - WHR) by receiver operating characteristic (ROC) curve analyses. METHODS 1,655 (45.8% men) participants of the MONICA-WHO/Vitoria Project, mean age 45 ± 11 y were investigated. Metabolic syndrome prevalence (ATP-III criteria) was 32.9%, hypertension was 42.4% and obesity was 19.2%. RESULTS Regarding the ability to identify hypertension, there was a significant WSR superiority in relation to BMI and WC (p < 0.05) regardless of gender, but WHR (p > 0.05). In relation to the ability to identify metabolic syndrome, there was a significant WSR superiority in relation to WHR in men (p < 0.001), but BMI and WC (p = 0.16 and p = 0.9), respectively. However, in women WSR was significantly superior in relation to WHR (p < 0.001) and BMI (p = 0.025), but WC (p = 0.8). The optimal WSR cutoffs are 0.52 and 0.53 for hypertension and 0.53 and 0.54 for metabolic syndrome, for men and women, respectively. CONCLUSION Abdominal obesity, identified by WSR as a surrogate, and not overall obesity (BMI as surrogate), is the simplest and best applicable obesity index associated to hypertension and metabolic syndrome in our population.

Gender Distribution of Serum Uric Acid and Cardiovascular Risk Factors: Population Based Study

FUNDAMENTO: Nao ha dados relativos a epidemiologia da hiperuricemia em estudos brasileiros de base populacional. OBJETIVO: Investigar a distribuicao de acido urico serico e sua relacao com variaveis demograficas e cardiovasculares. METODOS: Estudamos 1.346 individuos. A hiperuricemia foi definida como > 6,8 e > 5,4 mg/dL para homens e mulheres, respectivamente. A sindrome metabolica (SM) foi definida utilizando-se os criterios NCEP ATP III. RESULTADOS: A prevalencia de hiperuricemia foi de 13,2%. A associacao de acido urico serico (AUS) com fatores de risco cardiovasculares foi especifica para o genero: em mulheres, maiores niveis de AUS estiveram associados com IMC elevado, mesmo apos ajustes da pressao arterial sistolica para idade (PAS). Em homens, a relacao do AUS com o colesterol HDL esteve mediada pelo IMC, enquanto em mulheres, o AUS mostrou-se semelhante e dependente do IMC, independentemente dos niveis glicose e presenca de hipertensao. Nos homens, os triglicerideos, a circunferencia abdominal (CA) e a PAS explicaram 11%, 4% e 1% da variabilidade do AUS, respectivamente. Nas mulheres, a circunferencia abdominal e os triglicerideos explicaram 9% e 1% da variabilidade de AUS, respectivamente. Em comparacao com o primeiro quartil, homens e mulheres no quarto quartil apresentavam 3,29 e 4,18 vezes mais de aumento de risco de SM, respectivamente. As mulheres apresentaram uma prevalencia quase tres vezes maior de diabetes melito. Homens normotensos com MS apresentaram maiores niveis de AUS, independente do IMC. CONCLUSAO: Nossos resultados parecem justificar a necessidade de uma avaliacao baseada no genero em relacao a associacao do AUS com fatores de risco cardiovasculares, que se mostraram mais acentuados em mulheres. A SM esteve positivamente associada com AUS elevado, independentemente do genero. A obesidade abdominal e a hipertrigliceridemia foram os principais fatores associados com a hiperuricemia mesmo em individuos normotensos, o que pode adicionar maior risco para a hipertensao.BACKGROUND There is no data concerning the epidemiology of hyperuricemia in Brazilian population-based studies. OBJECTIVE To investigate the distribution of serum uric acid and its relationship with demographics and cardiovascular variables. METHODS We studied 1,346 individuals. Hyperuricemia was defined as ≥ 6.8 and ≥ 5.4 mg/dL for men and women, respectively. Metabolic syndrome (MS) was defined with NCEP ATP III criteria. RESULTS The prevalence of hyperuricemia was 13.2%. The association of serum uric acid (SUA) with cardiovascular risk factors was gender-specific: in women, higher SUA was associated with increasing BMI, even after adjustments for age-systolic blood pressure (SBP). In men, the relationship of SUA with HDLc was mediated by BMI, whereas in women, SUA was similar and dependent on BMI, regardless of glucose levels and presence of hypertension. In men, triglycerides, waist circumference (WC) and SBP explained 11%, 4% and 1% of SUA variability, respectively. In women, WC and triglycerides explained 9% and 1% of SUA variability, respectively. Compared to the first quartile, men and women in the fourth quartile had a 3.29 fold and 4.18 fold increase of MS risk, respectively. Women had almost three fold higher prevalence of diabetes mellitus. Normotensive men with MS presented higher SUA, regardless of BMI. CONCLUSION Our results seem to justify the need for gender-based evaluation regarding the association of SUA with cardiovascular risk factors, which was more pronounced in women. MS was positively associated with increasing SUA, regardless of gender. Abdominal obesity and hypertriglyceridemia were the main factors associated with hyperuricemia even in normotensive individuals, which may add a higher risk for hypertension.

Body Mass Index Is Not Independently Associated With Increased Aortic Stiffness in a Brazilian Population

BACKGROUND Obesity has been described as a predictor of cardiovascular mortality, and some studies have reported an association with obesity and increased aortic stiffness. Other studies have not identified obesity to be an independent risk factor. Therefore, the purpose of our study was to determine the association between aortic stiffness and obesity in the Brazilian population. METHODS A cross-sectional study recruited 1,662 individuals aged 25-64 years from the population of Vitória, Brazil following the guidelines of the MONICA-WHO Project. Anthropometric, clinical, and hemodynamic measurements and analyses of aortic stiffness (using carotid-femoral pulse wave velocity <PWV) were obtained in 1,608 subjects. RESULTS PWV correlated positively with age, systolic blood pressure (SBP), diastolic blood pressure (DBP), mean blood pressure, heart rate (HR), body mass index (BMI), waist circumference (WC), cholesterol levels, triglyceride levels, and blood glucose levels. A multivariate regression analysis demonstrated that the mean BP (β = 0.405, P < 0.01), age (β = 0.314, P < 0.01), HR (β = 0.107, P < 0.01), BMI (β = -103, P < 0.01), and blood glucose levels (β = 0.093, P < 0.01) explained nearly 37% of the PWV variability. A multivariate regression analysis using the WC instead of the BMI failed to reveal any significant effect of this parameter on the PWV. CONCLUSIONS In conclusion, our study failed to provide evidence of a positive, blood pressure (BP)-independent association between obesity on aortic stiffness. Our data suggests that the previously reported finding of an association between obesity and aortic stiffness was probably confounded by the progressive increase in BP observed in obesity.

Spectral analysis of heart rate variability with the autoregressive method

This work assessed the influence of the autoregressive model order (ARMO) on the spectral analysis of the heart rate variability (HRV). A sample of 68 R-R series obtained from digital ECG records of young healthy adults in the supine position was used. Normalized spectral indexes for each ARMO were compared by Friedman test followed by the Dunns procedure and statistical significance was set at P<0.05. The results showed that the AR method using orders from 9 to 25 produces normalized spectral parameters statistically similar and, hence, the algorithms commonly employed to estimate optimum order are not mandatory in this case.

Distribuição por gênero de ácido úrico sérico e fatores de risco cardiovascular: estudo populacional

FUNDAMENTO: Nao ha dados relativos a epidemiologia da hiperuricemia em estudos brasileiros de base populacional. OBJETIVO: Investigar a distribuicao de acido urico serico e sua relacao com variaveis demograficas e cardiovasculares. METODOS: Estudamos 1.346 individuos. A hiperuricemia foi definida como > 6,8 e > 5,4 mg/dL para homens e mulheres, respectivamente. A sindrome metabolica (SM) foi definida utilizando-se os criterios NCEP ATP III. RESULTADOS: A prevalencia de hiperuricemia foi de 13,2%. A associacao de acido urico serico (AUS) com fatores de risco cardiovasculares foi especifica para o genero: em mulheres, maiores niveis de AUS estiveram associados com IMC elevado, mesmo apos ajustes da pressao arterial sistolica para idade (PAS). Em homens, a relacao do AUS com o colesterol HDL esteve mediada pelo IMC, enquanto em mulheres, o AUS mostrou-se semelhante e dependente do IMC, independentemente dos niveis glicose e presenca de hipertensao. Nos homens, os triglicerideos, a circunferencia abdominal (CA) e a PAS explicaram 11%, 4% e 1% da variabilidade do AUS, respectivamente. Nas mulheres, a circunferencia abdominal e os triglicerideos explicaram 9% e 1% da variabilidade de AUS, respectivamente. Em comparacao com o primeiro quartil, homens e mulheres no quarto quartil apresentavam 3,29 e 4,18 vezes mais de aumento de risco de SM, respectivamente. As mulheres apresentaram uma prevalencia quase tres vezes maior de diabetes melito. Homens normotensos com MS apresentaram maiores niveis de AUS, independente do IMC. CONCLUSAO: Nossos resultados parecem justificar a necessidade de uma avaliacao baseada no genero em relacao a associacao do AUS com fatores de risco cardiovasculares, que se mostraram mais acentuados em mulheres. A SM esteve positivamente associada com AUS elevado, independentemente do genero. A obesidade abdominal e a hipertrigliceridemia foram os principais fatores associados com a hiperuricemia mesmo em individuos normotensos, o que pode adicionar maior risco para a hipertensao.BACKGROUND There is no data concerning the epidemiology of hyperuricemia in Brazilian population-based studies. OBJECTIVE To investigate the distribution of serum uric acid and its relationship with demographics and cardiovascular variables. METHODS We studied 1,346 individuals. Hyperuricemia was defined as ≥ 6.8 and ≥ 5.4 mg/dL for men and women, respectively. Metabolic syndrome (MS) was defined with NCEP ATP III criteria. RESULTS The prevalence of hyperuricemia was 13.2%. The association of serum uric acid (SUA) with cardiovascular risk factors was gender-specific: in women, higher SUA was associated with increasing BMI, even after adjustments for age-systolic blood pressure (SBP). In men, the relationship of SUA with HDLc was mediated by BMI, whereas in women, SUA was similar and dependent on BMI, regardless of glucose levels and presence of hypertension. In men, triglycerides, waist circumference (WC) and SBP explained 11%, 4% and 1% of SUA variability, respectively. In women, WC and triglycerides explained 9% and 1% of SUA variability, respectively. Compared to the first quartile, men and women in the fourth quartile had a 3.29 fold and 4.18 fold increase of MS risk, respectively. Women had almost three fold higher prevalence of diabetes mellitus. Normotensive men with MS presented higher SUA, regardless of BMI. CONCLUSION Our results seem to justify the need for gender-based evaluation regarding the association of SUA with cardiovascular risk factors, which was more pronounced in women. MS was positively associated with increasing SUA, regardless of gender. Abdominal obesity and hypertriglyceridemia were the main factors associated with hyperuricemia even in normotensive individuals, which may add a higher risk for hypertension.

Granulocyte colony-stimulating factor reduces mortality by suppressing ventricular arrhythmias in acute phase of myocardial infarction in rats.

Our aim was to evaluate the effects of granulocyte colony-stimulating factor (G-CSF) on early cardiac arrhythmias after myocardial infarction (MI) and the impact on survival. Male Wistar rats received repeated doses of 50 μg/kg G-CSF (MI-GCSF group) or vehicle (MI group) at 7, 3, and 1 days before surgery. MI was induced by permanent occlusion of left coronary artery. The electrocardiogram was obtained before occlusion and then for 30 minutes after surgery. Events and duration of ventricular arrhythmias were analyzed. The levels of connexin43 (Cx43) were measured by Western blot immediately before MI production. Survival was significantly increased in MI-GCSF pretreated group (74% versus 52.9% MI, P < 0.05). G-CSF pretreatment also significantly reduced the ventricular premature beats when compared with the untreated-MI group (201 ± 47 versus 679 ± 117, P < 0.05). The number and the duration of ventricular tachycardia were smaller in the MI-G-CSF group, as well as the number of ventricular fibrillation episodes (10% versus 69% in MI, P < 0.05). Cx43 levels were significantly increased by G-CSF treatment (1.27 ± 0.13 versus 0.86 ± 0.11; P < 0.05). The MI size 24 hours after occlusion was reduced by G-CSF pretreatment (36 ± 3% versus 44 ± 2% of left ventricle in MI group; P < 0.05). The increase of Cx43 expression in the heart may explain the reduced incidence in ventricular arrhythmias in the early phases after coronary artery occlusion in rats, thus increasing survival after MI.

Prevalence of cardiovascular risk factors and socioeconomic level among public-sector workers in Angola

BackgroundCardiovascular diseases are the leading cause of death in the majority of developed and developing countries. African countries are currently facing an increase in both cardiovascular and transmitted diseases. In addition, cardiovascular risk varies among different socioeconomic groups. Thus, we determined the prevalence of modifiable cardiovascular risk factors in apparently healthy public-sector workers and investigated possible relationships with socioeconomic status.MethodsWe employed a cross-sectional study comprising 42.2% (n = 615) of the public-sector workers at Agostinho Neto University, 48% (n = 294) male and 52% (n= 321) female, with ages between 20 and 72 years and from various socioeconomic groups. The study was conducted from February 2009 to December 2010. Personal, anthropometric, biochemical, hemodynamic, socioeconomic, and physical activity data were collected.ResultsThe prevalence rates of cardiovascular risk factors were as follows: hypertension, 45.2% (men 46.3%, women 44.2%, P > 0.05); hypercholesterolemia, 11.1% (men 10.5%, women 11.5%, P > 0.05); low high-density lipoprotein (HDL) cholesterol, 50.1% (men 36.9%, women 62.3%; P < 0.05); hypertriglyceridemia, 10.6% (men 12.6%, women 8.7%, P > 0.05); smoking, 7.2% (men 10.2%, women 4.4%; P < 0.05); diabetes, 5.7% (men 5.5%, women 5.9%, P > 0.05); overweight, 29.3% (men 27.3%, women 31.2%, P > 0.05); obesity, 19.6% (men 9.2%, women 29.0%; P < 0.05); sedentary lifestyle, 87.2% (men 83.0%, women 91,0%, P < 0.05); and left ventricular hypertrophy, 20% (men 32.0%, women 9.0%; P < 0.05). At least one risk factor was present in 27.7% of the sample; 15.2% had two risk factors, and 31.4% had three or more risk factors. Among the individuals with low socioeconomic status, 41.0% had three or more risk factors.ConclusionsThe results of this study suggest the existence of a high prevalence of multiple risk factors for cardiovascular disease in apparently healthy public-sector workers in Angola. The workers in lower socioeconomic groups had higher incidences of hypertension, smoking, and left ventricular hypertrophy.

Correlation between sodium and potassium excretion in 24- and 12-h urine samples

Low-sodium and high-potassium diets have been recommended as an adjunct to prevention and treatment of hypertension. Analysis of these nutrients in 24-h urine has been considered the reference method to estimate daily intake of these minerals. However, 24-h urine collection is difficult in epidemiological studies, since urine must be collected and stored in job environments. Therefore, strategies for shorter durations of urine collection at home have been proposed. We have previously reported that collecting urine during a 12-h period (overnight) is more feasible and that creatinine clearance correlated strongly with that detected in 24-h samples. In the present study, we collected urine for 24 h divided into two 12-h periods (from 7:00 am to 7:00 pm and from 7:00 pm to 7:00 am next day). A sample of 109 apparently healthy volunteers aged 30 to 74 years of both genders working in a University institution was investigated. Subjects with previous myocardial infarction, stroke, renal insufficiency, and pregnant women were not included. Significant (P < 0.001) Spearman correlation coefficients (rs) were found between the total amount of sodium and potassium excreted in the urine collected at night and in the 24-h period (rs = 0.76 and 0.74, respectively). Additionally, the 12-h sodium and potassium excretions (means ± SD, 95% confidence interval) corresponded to 47.3 ± 11.2%, 95%CI = 45.3-49.3, and 39.3 ± 4.6%, 95%CI = 37.3-41.3, respectively, of the 24-h excretion of these ions. Therefore, these findings support the assumption that 12-h urine collected at night can be used as a reliable tool to estimate 24-h intake/excretion of sodium and potassium.

Long-term use of low-dose spironolactone in spontaneously hypertensive rats: Effects on left ventricular hypertrophy and stiffness

The aim of the present study was to evaluate the effect of low-dose spironolactone initiated during the early stages of hypertension development and to assess the effects of chronic pressure overload on ventricular remodeling in rats. Male spontaneously hypertensive rats (SHRs) (4 weeks) were randomized to receive daily spironolactone (20 mg/kg) or vehicle (mineral oil) from 4 weeks to 8 months of age. Systolic blood pressure was measured non-invasively by tail-cuff pletysmography at baseline, 4 and 8 months. Hemodynamic assessment was performed at the end of treatment by arterial and ventricular catheterization. An in situ left ventricular pressure-volume curve was created to evaluate dilatation and wall stiffness. Systolic blood pressure at 1 month of age was higher in SHRs than in the Wistar group; it increased throughout the follow-up period and remained elevated with treatment (Wistar: 136 ± 2, SHR: 197 ± 6.8, SHR-Spiro: 207 ± 7.1 mmHg; p < 0.05). Spironolactone reduced cardiac hypertrophy (Wistar: 1.25 ± 0.03 SHR: 1.00 ± 0.03, SHR-Spiro: 0.86 ± 0.02 g; p < 0.05) and left ventricular mass normalized to body weight (Wistar: 2.51 ± 0.06, SHR: 2.70 ± 0.08, 2.53 ± 0.07 mg/g; p < 0.05). Moreover, the left ventricular wall stiffness that was higher in SHRs was partially reduced by spironolactone treatment (Wistar: 0.370 ± 0.032; SHR: 0.825 ± 0.058; SHR-Spiro: 0.650 ± 0.023 mmHg/ml; p < 0.05). Our results show that long-term spironolactone treatment initiated at the early stage of hypertension development reduces left ventricular hypertrophy and wall stiffness in SHRs.