RESUMO
An electrocardiographic recording method with an associated reading guide, designed for epidemiological studies on Chagas' disease, was tested to assess its diagnostic reproducibility. Six cardiologists from five countries each read 100 electrocardiographic (ECG) tracings, including 30 from chronic chagasic patients, then reread them after an interval of 6 months. The readings were blind, with the tracings numbered randomly for the first reading and renumbered randomly for the second reading. The physicians, all experienced in interpreting ECGs from chagasic patients, followed printed instructions for reading the tracings. Reproducibility of the readings was evaluated using the kappa (kappa) index for concordance. The results showed a high degree of interobserver concordance with respect to the diagnosis of normal vs. abnormal tracings (kappa = 0.66; SE 0.02). While the interpretations of some categories of ECG abnormalities were highly reproducible, others, especially those having a low prevalence, showed lower levels of concordance. Intraobserver concordance was uniformly higher than interobserver concordance. The findings of this study justify the use by specialists of the recording of readings method proposed for epidemiological studies on Chagas' disease, but warrant caution in the interpretation of some categories of electrocardiographic alterations.
Assuntos
Doença de Chagas/diagnóstico , Eletrocardiografia , Argentina/epidemiologia , Doença de Chagas/epidemiologia , Métodos Epidemiológicos , Estudos de Avaliação como Assunto , HumanosRESUMO
Eleven patients with moderate to severe hypertension were studied at the Vargas Hospital of Caracas. The patients were pretreated with labetalol, 800 to 1200 mg/day, orally, over a period of 1 week, after which an intravenous infusion of dopamine, .5 to 3 micrograms/kg/minute, was given. Two intravenous dopamine infusions (30 minutes each) were performed before and after the injection of metoclopramide (30 mg, intravenous bolus). Two washout periods were also included before and after metoclopramide administration. Dopamine induced a decrease of blood pressure from 171.9 + 6.35/103.6 +/- 3.12 to 152.7 +/- 7.55/93.8 +/- 2.97 mm Hg (P < .001) without altering heart rate, and it increased plasma insulin levels from 8.29 +/- .70 microU/mL to 12.09 +/- 1.83 microU/mL (P < .01). Metoclopramide caused no changes of blood pressure or plasma insulin levels. Hypotensive responses and plasma insulin increases due to dopamine were blocked by metoclopramide, however. The authors conclude that a dopaminergic receptor may be involved in some cardiovascular responses and in modulating insulin secretion in humans.
Assuntos
Pressão Sanguínea/efeitos dos fármacos , Antagonistas de Dopamina , Hipertensão/tratamento farmacológico , Insulina/sangue , Labetalol/uso terapêutico , Metoclopramida/farmacologia , Glicemia/análise , Dopamina/administração & dosagem , Dopamina/farmacologia , Feminino , Humanos , Infusões Intravenosas , Masculino , Metoclopramida/administração & dosagem , Pessoa de Meia-Idade , Pré-MedicaçãoRESUMO
Eleven patients with moderate to severe hypertension were pre-treated with oral labetalol 800-1200 mg/day for one week, prior to receiving two i.v. infusions of dopamine 1-3 micrograms/kg/min each of 30 min each, before and after the i.v. bolus injection of metoclopramide 30 mg. There were washout periods before and after the metoclopramide administration. Dopamine induced a significant decrease of blood pressure from 172/104 to 153/94 mm Hg without altering heart rate, and it increased the plasma insulin level from 8.3 to 12.1 microU.ml-1. Metoclopramide did not itself affect blood pressure or plasma insulin, but it did block the hypotensive response and rise in plasma insulin due to dopamine. We conclude that the pharmacological actions of intravenous dopamine on the cardiovascular system and on insulin secretion may be mediated by dopaminergic receptor stimulation.
Assuntos
Pressão Sanguínea/efeitos dos fármacos , Dopamina/farmacologia , Hipertensão/fisiopatologia , Insulina/sangue , Glicemia/metabolismo , Dopamina/administração & dosagem , Feminino , Frequência Cardíaca/efeitos dos fármacos , Humanos , Hipertensão/sangue , Hipertensão/tratamento farmacológico , Infusões Intravenosas , Labetalol/uso terapêutico , Masculino , Metoclopramida/farmacologia , Pessoa de Meia-IdadeRESUMO
A randomized double-blind, comparative study, with a new slow release preparation of nifedipine (nifedipine-retard), was undertaken in patients with mild, moderate and severe essential hypertensión WHO (stage I-II). After a two-week placebo period, patients were divided into three groups: 1) group I received nifedipine-retard 20 mg orally twice daily; 2) group II received acebutolol 200 mg orally twice daily; and 3) group III received nifedipine-retard 20 mg once daily plus acebutolol 200 mg orally once daily. All three dosage regimens were administered for six weeks. Nifedipine-retard (group I) reduced supine blood pressure from 162 ñ 4.2/105 ñ 1.4 mmHg (21.6 ñ 0.5/14.0 ñ 0.2 Pa) to 139 ñ 4.2/92 ñ 2.6 mmHg (18.5 ñ 0.5/12.3 ñ 0.3 kPa) and slighrly increased the heart rate. Acebutolol (group I) reduced supine blood pressure from 163 ñ 5.3/107 ñ 2.8 mmHg (21.7-0.7/14.2 ñ 0.4 kPa) to 144 ñ 5.0/93 ñ 3.7 mmHg (192 ñ 0.7/12.4 ñ 0.5 kPa) and decreased the heart rate. Nifedipine retard plus acebutolol (group III) reduced supine blood presure from 144 ñ 3.0/101 ñ 1.3 mmHg (19.2 ñ 0.4/13.4 ñ 012 kPa) to 123 ñ 3.4/84 ñ 2.8 mmHg (16.4 ñ 0.5/11.2 ñ 0.4 kPa) and did not significantly alter the heart the heart rate. There was a significant correlation (r = 0.65, p < 0.03) betwee baseline blood pressure and diastolic blood pressure after six weeks of therapy nifedipine-retard. There was a no significant trend between the age of patients and decrease of diastolic blood pressure, positive for nifedipine-retard, and negative for acebutolol. There was a low incidence of side effects with all dosage regimens..
Assuntos
Adulto , Pessoa de Meia-Idade , Humanos , Masculino , Feminino , Acebutolol/farmacologia , Hipertensão/efeitos dos fármacos , Nifedipino/farmacologiaRESUMO
El objetivo de este estudio fue el de investigar el efecto de la Bromocriptina sobre los sistemas Cardiovasculares, Renal y sobre el Sistema Renina-Angiotensina-Aldosterona. Los agonistas dopaminérgicos, tales como la dopamina y sus derivados, inducen aumento de la contractibilidad cardíaca, natriuresis y aumento del flujo sanguíneo renal por activación de recptores adrenérgicos y dopaminérgicos. En el presente estudio se definen los efectos cardiovasculares, renales, y sobre el sistema Renina-Angiotensina-Aldosterona de un activador dopaminérgico-bromocriptina en un programa abierto con placebo comparativo cruzado en 9 pacientes con hipertensión leve y moderada. Se midieron los siguientes parámetros durante un período de placebo (de 4 semanas) y durante un período de bromocriptina (de 8 semanas) en dosis de 2,5 mg-5 mg/día: Presión Arterial (PA); Frecuencia Cardíaca (FC); Fracción de Eyección (FE); y Fracción de Acortamiento (FA) por ecocardiografía; respuesta cardiovascular del ejercicio submáximo en una cincha sin fin y utilizando la metodología de Bruce; depuración de Urea (cl U) (por método colorimétrico); depuración de Creatinina (Cl Cr) (por métodos cinéticos); Aldosterona (por radioinmunoensayo); Actividad de renina plasmática (PRA) (por radioinmunoensayo). La Bromocriptina redujo significativamente la presión arterial promedio de 155/105 a 136/92 mmHg. También produjo un descenso importante de la frecuencia cardíaca en posición de pie; pero no así en posición supina. Respecto a la función cardiovascular no se observaron cambios significativos en la fracción de eyección (Fa) y de acortamiento (Fa)..
Assuntos
Adulto , Pessoa de Meia-Idade , Humanos , Masculino , Feminino , Bromocriptina/farmacologia , Hipertensão/efeitos dos fármacosRESUMO
An open, non-comparative study, with a new calcium antagonist-tiapamil, was undertaken in 22 patients with mild and moderate essential hypertension (stage I-II WHO). After a two-week placebo period, patients were treated with tiapamil, 300-600 mg twice daily during a period of six weeks (Dose-finding period). Thereafter patients were continued on tiapamil during a 54 week period (Long-term follow-up). In some patients it was necessary to add the diuretic hydrochlorothiazide to obtain adequate control of the arterial hypertension. Monotherapy with tiapamil normalized supine diastolic blood pressure after the first six weeks in 17 of the 21 evaluable patients, and reduced it by greater than or equal to 10 mmHg (1.3 kPa) from baseline without normalization in two patients. In the two remaining cases the decrease was less than 10 mmHg. The optimal dose administered at six weeks in those patients who responded to treatment (normalization or decrease by greater than or equal to 10 mmHg.) was 600 mg/day in 32% of the cases, 750-900 mg/day in 47% and more than 900 mg/day in 21%. After completion of the dose-finding part, 19 patients continued treatment for a further 54 weeks. In 16 out of 19 patients hydrochlorothiazide was added to enhance the antihypertensive effect. All three patients who received tiapamil monotherapy throughout the trial, had normalized supine diastolic blood pressure on completing the study. In the 16 patients with the combination therapy, the addition of hydrochlorothiazide led in two patients to no further decrease in supine diastolic blood pressure, to an additional decrease by less than 10 mmHg in ten patients and by greater than or equal to 10 mmHg in four in comparison with the values obtained before starting combination therapy. At the end of the study 11 of these 16 patients had normalized supine diastolic blood pressure. The mean daily dose was 900 +/- 45 mg of tiapamil and 39 +/- 4 mg of hydrochlorothiazide. Both monotherapy and the combination regimen were well tolerated, and no effects attributable to drug interactions were observed. It may be concluded that tiapamil in oral doses of 300-600 mg twice daily is an effective antihypertensive agent with an excellent tolerance when administered for a period of 54 weeks.