This study analyzed, with spectral techniques, the effects of atenolol or metoprolol on RR interval variability in 20 patients 4 weeks after the first uncomplicated myocardial infarction. Beta blocker-induced bradycardia was associated with a significant increase in the average 24-hour values of RR variance (from 13,886 +/- 1,479 to 16,728 +/- 1,891 ms2) and of the normalized power of the high-frequency component (from 22 +/- 1 to 28 +/- 2 normalized units), whereas the low-frequency component was greatly reduced (from 60 +/- 3 to 50 +/- 3 normalized units). When considering day and nighttime separately, the effects of both drugs were more pronounced in the daytime. In addition, a marked attenuation was observed in the circadian variation of the low-frequency component after beta blockade. As a result, the early morning increase of the spectral index of sympathetic modulation was no longer detectable. These results indicate that beta-blocker administration has important effects on RR interval variability and on its spectral components. The observed reduction in signs of sympathetic activation and the increase in vagal tone after beta blockade help to explain the beneficial effects of these drugs after myocardial infarction. However, the potential clinical relevance of the increase in RR variance remains to be established.

Effects of beta blockers (atenolol or metoprolol) on heart rate variability after acute myocardial infarction.

Increased survival with β-blockers: Importance of ancillary properties

The effects of 1 month of treatment with either verapamil or metoprolol on several aspects of platelet function were studied at rest and during physical exercise or mental stress in patients with stable angina pectoris participating in the Angina Prognosis Study in Stockholm. Platelet aggregability was measured by filtragometry ex vivo, which reflects platelet aggregability in vivo and by Born aggregometry in vitro. Platelet secretion in vivo was assessed by measurements of β-thromboglobulin in plasma. Verapamil reduced plasma norepinephrine levels (from 2.6 ± 1.0 to 2.2 ± 1.0 nmol/L; p

Platelet aggregability in vivo is attenuated byverapamil but not bymetoprolol in patients with stable angina pectoris

Objetivo - Avaliar aspectos epidemiologicos, clinicos e terapeuticos de idosos com doencas cardiovasculares (DCV), no Brasil. Metodos - Idosos com DCV, atendidos em 36 servicos de Cardiologia e Geriatria do Brasil, foram investigados atraves de questionario aplicado aos que tinham consulta marcada para o periodo analisado (um mes). Resultados - Estudados 2196 idosos de 65 a 96 anos, sendo 60% mulheres e analisados os fatores de risco: sedentarismo (74%), pressao arterial (PA) elevada (53%), LDL colesterol aumentado (33%), colesterol total aumentado (30%), obesidade (30%), HDL-colesterol diminuido (15%), diabetes (13%) e tabagismo (6%). Observou-se maior prevalencia nas mulheres, com tres ou mais fatores de risco. O principal motivo de consulta foi a PA elevada (48%). Teste ergometrico e cinecoronariografia, foram mais solicitados para os homens. Os diagnosticos mais comuns foram hipertensao arterial sistemica (HAS) (67%) e insuficiencia coronaria (ICo) (29%). Os medicamentos mais utilizados foram diureticos (42%). Conclusao - Foi observada alta prevalencia de fatores de risco (93%), principalmente nas mulheres; sedentarismo, como fator de risco mais frequente, aumentando de prevalencia com a idade; HAS, como principal motivo de consulta e diagnostico; menor investigacao e diagnostico de ICo em mulheres; diureticos, como os farmacos mais frequentemente prescritos; insuficiencia cardiaca como principal doenca associada a internacao (31%) e atendimento de emergencia (10%).

/pdf/estudo-multicentrico-de-idosos-atendidos-em-ambulatorios-de-28zggwm2kz.pdf

Estudo multicêntrico de idosos atendidos em ambulatórios de cardiologia e geriatria de instituições brasileiras

Chapter 15 – Cardiovascular Physiology: Central and Autonomic Regulation

By the mid 1960s a beneficial effect of post-myocardial infarction treatment with beta-blockade had been proposed. However, it was not until 1981 that large clinical trials clearly demonstrated a beneficial effect both in terms of reduction in mortality and morbidity. Today treatment with beta-blockers both in the acute phase of acute myocardial infarction as well as in the stable post-myocardial infarction patient is well established. In this review article, different aspects of early and late treatment with beta-adrenoceptor blockers are discussed. The cardioprotective effects of beta-blockers on mortality and morbidity should not be considered class effects valid for all beta-blockers. Pooled data have clearly demonstrated that beta-blockers with intrinsic sympathomimetic activity have less marked effects. Impressive effects on mortality and morbidity have been obtained with propranolol, timolol, and metoprolol, which are noncardioselective as well as more beta 1-selective (metoprolol), but they are all lacking intrinsic sympathomimetic activity and, furthermore, have a relatively high degree of lipophilicity. It is clear that acute beta-adrenoceptor blockade in suspected acute myocardial infarction reduces mortality and morbidity as well as complications such as chest pain and ventricular arrhythmias during the acute phase. In post-myocardial infarction treatment, it is clear that both mortality and morbidity are reduced. Reports from extended follow-ups after termination of initial double-blind beta-blocker studies in postinfarction patients indicate that withdrawal of the active treatment may increase mortality after cessation of treatment. This is observed despite measures having been taken to avoid so-called acute withdrawal phenomena.(ABSTRACT TRUNCATED AT 250 WORDS)

Myocardial infarction. Effects of beta-blockade.

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Myocardial infarction. Effects of beta-blockade.