Effects of carvedilol in heart failure due to dilated cardiomyopathy. Results of a double-blind randomized placebo-controlled study (CARIBE study)

OBJECTIVE: To assess the effects of carvedilol in patients with idiopathic dilated cardiomyopathy. METHODS: In a double-blind randomized placebo-controlled study, 30 patients (7 women) with functional class II and III heart failure were assessed. Their ages ranged from 28 to 66 years (mean of 43±9 years), and their left ventricular ejection fraction varied from 8% to 35%. Carvedilol was added to the usual therapy of 20 patients; placebo was added to the usual therapy of 10 patients. The initial dose of carvedilol was 12.5 mg, which was increased weekly until it reached 75 mg/day, according to the patient's tolerance. Clinical assessment, electrocardiogram, echocardiogram, and radionuclide ventriculography were performed in the pretreatment phase, being repeated after 2 and 6 months of medication use. RESULTS: A reduction in heart rate (p=0.016) as well as an increase in left ventricular shortening fraction (p=0.02) and in left ventricular ejection fraction (p=0.017) occurred in the group using carvedilol as compared with that using placebo. CONCLUSION: Carvedilol added to the usual therapy for heart failure resulted in better heart function.

Can the Cardiopulmonary 6-Minute Walk Test Reproduce the Usual Activities of Patients with Heart Failure?

OBJECTIVE: The 6-minute walk test is an way of assessing exercise capacity and predicting survival in heart failure. The 6-minute walk test was suggested to be similar to that of daily activities. We investigated the effect of motivation during the 6-minute walk test in heart failure. METHODS: We studied 12 males, age 45±12 years, ejection fraction 23±7%, and functional class III. Patients underwent the following tests: maximal cardiopulmonary exercise test on the treadmill (max), cardiopulmonary 6-minute walk test with the walking rhythm maintained between relatively easy and slightly tiring (levels 11 and 13 on the Borg scale) (6EB), and cardiopulmonary 6-minute walk test using the usual recommendations (6RU). The 6EB and 6RU tests were performed on a treadmill with zero inclination and control of the velocity by the patient. RESULTS: The values obtained in the max, 6EB, and 6RU tests were, respectively, as follows: O2 consumption (ml.kg-1.min-1) 15.4±1.8, 9.8±1.9 (60±10%), and 13.3±2.2 (90±10%); heart rate (bpm) 142±12, 110±13 (77±9%), and 126±11 (89±7%); distance walked (m) 733±147, 332±66, and 470±48; and respiratory exchange ratio (R) 1.13±0.06, 0.9±0.06, and 1.06±0.12. Significant differences were observed in the values of the variables cited between the max and 6EB tests, the max and 6RU tests, and the 6EB and 6RU tests (p<0.05). CONCLUSION: Patients, who undergo the cardiopulmonary 6-minute walk test and are motivated to walk as much as they possibly can, usually walk almost to their maximum capacity, which may not correspond to that of their daily activities. The use of the Borg scale during the cardiopulmonary 6-minute walk test seems to better correspond to the metabolic demand of the usual activities in this group of patients.

Efeitos sedativos e cardiovasculares do midazolam e do diazepam, associados ou não a clonidina, em pacientes submetidos a estudos hemodinâmicos por suspeita de doença arterial coronariana

FUNDAMENTO: A sedação durante a cineangiocoronariografia tem sido pouco estudada e saber qual é a melhor droga para sedar esses pacientes é um questionamento importante. OBJETIVO: Avaliar a qualidade da sedação e os efeitos sobre a freqüência cardíaca (FC) e a pressão arterial (PA) do midazolam e do diazepam, associados ou não a clonidina, em pacientes com suspeita de doença coronariana. MÉTODOS: Foi desenvolvido ensaio clínico prospectivo, duplo-cego, randomizado, controlado, com 160 pacientes divididos em cinco grupos de 32 pacientes cada, de acordo com o fármaco utilizado: grupo C (clonidina 0,5 µg/kg); grupo M (midazolam 40 µg/kg); grupo MC (associação de midazolam 40 µg/kg e clonidina 0,5 µg/kg); grupo D (diazepam 40 µg.kg); e grupo DC (associação de diazepam 40 µg/kg e clonidina 0,5 µg/kg). A sedação foi avaliada com base na escala de Ramsay e no consumo de meperidina 0,04 mg.kg-1. A PA invasiva, a FC e o escore de sedação foram analisados a cada cinco minutos em quatro diferentes momentos. RESULTADOS: Os pacientes que utilizaram midazolam apresentaram maiores escores de sedação e variação da FC e da PA (p < 0,05). Os que utilizaram diazepam ou clonidina tiveram menores escores de sedação e mais satisfatórios para a realização do exame e apresentaram menor variação da PA e da FC (p > 0,05). CONCLUSÃO: O midazolam foi associado a maior efeito sedativo e cardiovascular enquanto o diazepam causou menor efeito sedativo e cardiovascular. A clonidina e o diazepam tiveram efeitos semelhantes na PA, na FC e na sedação.