Guido Aranha Rosito

Intrinsic sinus and atrioventricular node electrophysiologic adaptations in endurance athletes.

OBJECTIVES In the present study, we evaluated sinus and atrioventricular (AV) node electrophysiology of endurance athletes and untrained individuals before and after autonomic pharmacologic blockade. BACKGROUND Endurance athletes present a higher prevalence of sinus bradycardia and AV conduction abnormalities, as compared with untrained individuals. Previous data from our laboratory suggest that nonautonomic factors may be responsible for the longer AV node refractory period found in well-trained athletes. METHODS Six aerobically trained male athletes and six healthy male individuals with similar ages and normal rest electrocardiograms were studied. Maximal oxygen uptake (O(2)max) was measured by cardiopulmonary testing. The sinus cycle length (SCL), AV conduction intervals, sinus node recovery time (SNRT), Wenckebach cycle (WC) and anterograde effective refractory period (ERP) of the AV node were evaluated by invasive electrophysiologic studies at baseline, after intravenous atropine (0.04 mg/kg) and after addition of intravenous propranolol (0.2 mg/kg). RESULTS Athletes had a significantly higher O(2)max as compared with untrained individuals. The SCL was longer in athletes at baseline, after atropine and after the addition of propranolol for double-autonomic blockade. The mean maximal SNRT/SCL was longer in athletes after atropine and after propranolol. The WC and anterograde ERP of the AV node were longer in athletes at baseline, after atropine and after propranolol. CONCLUSIONS Under double-pharmacologic blockade, we demonstrated that sinus automaticity and AV node conduction changes of endurance athletes are related to intrinsic physiology and not to autonomic influences.

Dose-dependent biphasic effect of ethanol on 24-h blood pressure in normotensive subjects.

The vasodilation that follows acute alcohol intake is hard to conciliate with the high prevalence of hypertension detected in those persons who consume regular amounts of alcohol. In this experiment we examined early and late hemodynamic effects of acute administration of water and of 15 g, 30 g, and 60 g of alcohol in 40 normal men, aged 19 to 30 years, using 24-h ambulatory blood pressure monitoring (ABPM). Mean systolic and diastolic blood pressures were each approximately 4 mm Hg lower during the period immediately after ingestion of 60 g (v 0 g) of ethanol, and were 7 and 4 mm Hg higher, respectively, at night. The day minus night differences displayed a dose-response curve both for systolic (P < .001) and diastolic blood pressure (P = .045). Three subjects in the 60-g group had more than 50% of nightly blood pressure loads in the hypertensive range against none in the remaining groups (P < .01). In conclusion, our findings suggest that acute alcohol intake elicits a biphasic hemodynamic response, causing, first, vasodilatation and, later, a pressor effect. The higher prevalence of hypertension in alcohol abusers seen in epidemiological surveys may be, in part, a result of measurements done in the period of transiently increased blood pressure during ethanol washout.

Intracerebroventricular administration of nanogram amounts of β-endorphin and Met-enkephalin causes retrograde amnesia in rats

The intracerebroventricular (icv) administration of 5.0 or 25.0 ng of beta-endorphin or Met-enkephalin causes retrograde amnesia for a shuttle avoidance task ion rats. In both cases, the higher dose was more effective than the lower one. The present results confirm previous similar findings obtained using systemic administrations of these compounds, and suggest that the amnestic effect of beta-endorphin and Met-enkephalin is mediated centrally.

Blood pressure effects of antihypertensive drugs and changes in lifestyle in a Brazilian hypertensive cohort

Background The antihypertensive efficacy of drug therapy and of some nonpharmacologic recommendations has been demonstrated in controlled clinical trials, but not in a clinical setting. Objective To assess the antihypertensive effectiveness of drug therapy and of three nonpharmacologic recommendations (loss of weight, salt-intake restriction, and physical exercise). Design A prospectively planned cohort study. Setting A hospital-based hypertensive outpatient clinic. Patients We studied 637 patients (65.5% women) with systolic blood pressures above 140 mmHg or diastolic blood pressures above 90 mmHg, corresponding to 76% of 839 patients who were administered a prescription for hypertension and who returned for the first follow-up visit 3.5 months later on average. Methods The nonpharmacologic prescription consisted of salt-intake restriction for all, weight reduction for overweight patients, and practice of aerobic physical exercise for those for whom it was not contraindicated; 60% of the patients were treated with drugs according to standard recommendations. Patients treated with drugs were compared with untreated subjects; for the nonpharmacologic interventions, the groups were compared according to their reported compliances with the recommendations (at least some compliance versus none). The main outcome measures were variations in systolic and diastolic blood pressures between the baseline evaluation and the first follow-up visit and an improvement in prognosis, represented by a favorable change in the classification of the blood pressure (according to Joint National Committee V criteria). Results The cohort constituted predominantly low-income, middle-aged, overweight white women, with low-to-moderate hypertension of long duration. The group treated with drugs exhibited the greatest reduction in blood pressure, with clinical significance even discounting the losses in follow-up; the group of patients who reported compliance with the low-energy-intake diet also showed a consistent antihypertensive effect, which was still detectable on the occasion of the third follow-up visit 9 months after the first prescription; reported compliance with a low-sodium diet and practice of physical exercise were not associated with a reduction in blood pressure; among a subset of the patients, reported compliance with the salt-intake-restricted diet did not reduce the amount of sodium to the theoretical antihypertensive threshold. It was not possible to determine whether the lack of an antihypertensive effect of physical exercise for this cohort was secondary to a misreport of the extent of compliance or to an absence of effect of the intensity of training prescribed. The effects of drug therapy and compliance with a low-energy-intake diet were shown to be independent of other interventions or confounders. Conclusion The antihypertensive effect of drugs demonstrated in well-controlled clinical trials is achievable in clinical practice. The recommendation to lose weight was the only nonpharmacologic intervention with a detectable antihypertensive effect in this cohort. The absence of effect of a low-sodium diet is probably secondary to the insufficient reduction in the amount of salt consumed. The lack of an antihypertensive effect of physical exercise could reflect either a misreported compliance or an absence of effect of the intensity of training recommended in this study.

Diurnal variation of vascular diameter and reactivity in healthy young men

The higher incidence of cardiovascular events in the morning is accompanied by an increased vascular tone. However, there are few published studies designed to evaluate the diurnal variation of vascular and endothelial parameters in healthy subjects. In the present investigation, we evaluated the diurnal variation in brachial artery diameter (BAD), flow-mediated dilation (FMD) and endothelium-independent dilation (NFMD) in a homogeneous sample of healthy non-smoker young men. Fifty subjects aged 20.8 +/- 0.3 years (range: 18 to 25 years) were investigated by brachial artery ultrasound. Exclusion criteria were female gender and evidence of clinically significant health problems, including obesity. Volunteers were asked to rest and avoid fat meals as well as alcoholic beverages 48 h before and until completion of the evaluations. BAD, FMD and NFMD were measured at 7 am, 5 pm, and 10 pm and tested by repeated measures ANOVA. BAD was smaller at 7 am (mean +/- SEM, 3.8 +/- 0.1 mm) in comparison with 5 pm (3.9 +/- 0.1) and 10 pm (4.0 +/- 0.1 mm; P < 0.001). FMD values did not change significantly during the day, while NFMD increased more at 7 am (18.5 +/- 1.1%), when compared to 15.5 +/- 0.9% at 10 pm and 15.5 +/- 0.9% at 5 pm (P = 0.04). The physiological state of vasoconstriction after awakening, with preserved capability to dilate in the morning, should be considered to be part of the healthy cardiovascular adaptation before considering later life risk factors and endothelial dysfunction.

Pre-training adrenaline recovers the amnestic effect of Met-enkephalin in demedullated rats.

The intracerebroventricular administration of 25 ng of Met-enkephalin causes retrograde amnesia for a shuttle avoidance task in intact rats. In demedullated rats, this effect of Met-enkephalin was lost. Intraperitoneal injection of 1.2 micrograms/kg adrenaline recovered the amnestic effect of Met-enkephalin. These results confirm the idea that the amnestic effect of Met-enkephalin is centrally mediated and that adrenal enkephalins do not seem to be important to the amnestic effect of Met-enkephalin since adrenaline recovers this effect in demedullated rats.

Variabilidade entre cardiologistas na abordagem aos pacientes em prevenção secundária da cardiopatia isquêmica

OBECTIVE: To compare the management of patients with ischemic heart disease being followed up in a general cardiology outpatient clinic with that of patients being followed up in an outpatient clinic specific for ischemic heart disease, emphasizing the lipid profile and the pharmacological treatment prescribed. METHODS: Data were collected from the medical records of 52 patients consecutively treated in the outpatient clinic for ischemic heart disease (group I) and of 43 patients treated in the general cardiology outpatient clinic (group II), the anatomical diagnosis of ischemic heart disease being the basic condition for their inclusion in the study. The criteria for dyslipidemia were as follows: total cholesterol > 200 mg/dL or LDL-cholesterol > 100 mg/dL, or both, in patients using or not lipid-lowering drugs, and the use of lipid-lowering drugs, even when the total cholesterol or LDL-cholesterol levels were < 200 mg/dL and 100 mg/dL, respectively, or both. The Fisher exact test was used for comparing the variables, and a 2-tailed p < 0.05 was accepted as significant. RESULTS: Demographic characteristics, risk factors for ischemic heart disease, prevalence of previous myocardial infarction, and previous revascularization procedures showed no significant differences between the patients in groups I and II. In group I, 98% of the patients received aspirin, while, in group II, 83% of the patients received that drug (p=0.02). In regard to the use of lipid-lowering drugs, the prevalences were 60% in group I and 19% in group II (p=0.001). The lipid profile examination was requested for 98% of group I individuals and 79% of group II individuals (p=0.003). CONCLUSION: In regard to new medical evidence, mainly prescription of aspirin and lipid-lowering drugs, the management was more reliable in the outpatient clinic specifically aimed at treating ischemic heart disease.

Pharmacological and clinical evidence for the use of low-molecular-weight heparins in acute coronary syndromes

Hospital de Clinicas de Porto Alegre and Faculdade de Medicina da UniversidadeFederal do Rio Grande do SulMailing address: Guido Aranha Rosito - Servico de Cardiologia - Hospital deClinicas de Porto Alegre - Rua Ramiro Barcelos, 2350 - 90035-007 - Porto Alegre,RS, Brazil, E-mail: guidorosito@cpovo.netEnglish version by Stela Maris C. e Gandour

Diagnóstico de hipertensão arterial sistêmica: evidências de que os critérios contemporâneos devem ser revistos

It has been recommended to take the average of several blood pressure (BP) determinations with a sphygmomanometer to diagnose hypertension, but there is no agreement on the reading numbers. PURPOSE. Describing the behavior of BP readings taken in three different days to establish the classificatory BP in an outpatient hypertension clinic. METHOD. In the outpatient hypertension clinic of the Clinical Pharmacology Division of the Hospital de Clinicas de Porto Alegre, we use the mean of six readings taken in three different days to establish the classificatory blood pressure, except for those with very high or low values in the first day. In this report we describe the behavior of BP in 58 patients submitted to this routine. RESULTS. The mean of systolic (SBP) and diastolic (DBP) blood pressures decreased from the first to the 6th reading (ANOVA for repeated measurements: F = 4.45, P = 0.001 for SBP and F = 5.54, P < 0.001 for DBP). Afterward, the patients were classified into two groups according their first SBP and DBP reading. The decreasing in both SBP and DBP was confined to those with the first measurement in the upper half of the entire group (ANOVA: F = 8.03; P < 0.0001 for SBP and F = 6.33, P <0.0001 for DBP). Regression to the mean and some reactiveness in the first day are possible explanations for this. CONCLUSION. These data corroborate that the hypertension diagnosis should not be based in an single blood pressure determination and suggest that the recommendation to diagnose severe hypertension based on high values in the first two read-ings could misclassify some patients.

Prevalence of Cardiovascular Risk Factors in Hemodialysis Patients - TheCORDIAL Study

Background There are scarce epidemiological data on cardiovascular risk profile of chronic hemodialysis patients in Brazil. Objective The CORDIAL study was designed to evaluate cardiovascular risk factors and follow up a hemodialysis population in a Brazilian metropolitan city. Methods All patients undergoing regular hemodialysis for chronic renal failure in all fifteen nephrology centers of Porto Alegre were considered for inclusion in the baseline phase of the CORDIAL study. Clinical, laboratory and demographic data were obtained in medical records and in structured individual interviews performed in all patients by trained researchers. Results A total of 1215 patients were included (97.3% of all hemodialysis patients in the city of Porto Alegre). Their average age was 58.3 years old, 59.5% were male and 62.8% were white. The prevalence of cardiovascular risk factors observed was 87.5% for hypertension, 84.7% for dyslipidemia, 73.1% for sedentary lifestyle, 53.7% for tobacco use, and 35.8% for diabetes. In a multivariate adjusted analysis, we found that sedentary lifestyle (p = 0.032, PR 1.08 - 95%CI: 1.01-1.15), dyslipidemia (p = 0.019, PR 1.08 - 95%CI: 1.01-1.14), and obesity (p < 0.001, PR 1.96 - 95%CI: 1.45-2.63) were more frequent in women; and hypertension (p = 0.018, PR 1.06 - 95%CI: 1.01-1.11) and tobacco use (p = 0.006, PR 2.7 - 95%CI: 1.79-4.17) were more often found among patients under 65 years old. Sedentary lifestyle was independently associated with time in dialysis less than 12 months (p < 0.001, PR 1.23 - 95% CI: 1.14-1.33). Conclusion Hemodialysis patients in this southern metropolitan Brazilian city have a high prevalence of cardiovascular risk factors resembling many northern countries.