RESUMO
A decrease in nocturnal serum melatonin levels was reported in patients with clinically uncharacterized coronary artery disease. To assess whether there was a correlation between melatonin production and disease stage, we measured the nocturnal urinary excretion of 6-sulphatoxymelatonin (an index of blood melatonin concentration) in patients with chronic stable or unstable coronary disease and in a group of age-matched controls. Three groups of individuals were studied: a) 24 healthy subjects (mean age: 63 +/- 13 yr); b) 32 patients with chronic, stable, coronary disease (62 +/- 11 yr); and c) 27 patients with unstable angina (62 +/- 12 yr). For 6-sulphatoxymelatonin measurement, urine was collected from 18:00 to 06:00 hr, within 48 hr of hospitalization in the case of unstable angina. 6-Sulphatoxymelatonin was measured by a specific radioimmunoassay. Urinary 6-sulphatoxymelatonin excretion was significantly lower in unstable angina patients than in healthy subjects or in patients with stable angina. 6-Sulphatoxymelatonin correlated negatively with age in healthy subjects, but not in coronary patients. 6-Sulphatoxymelatonin excretion in patients treated with beta-adrenoceptor blockers did not differ significantly from coronary patients not receiving beta-blockers. The results indicate that patients with coronary disease have a low melatonin production rate, with greater decreases in those with higher risk of cardiac infarction and/or death.
Assuntos
Doença das Coronárias/urina , Melatonina/análogos & derivados , Melatonina/urina , Adulto , Idoso , Idoso de 80 Anos ou mais , Envelhecimento/urina , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , RadioimunoensaioRESUMO
AIMS: The objective of this study was to ascertain the effect of intravenous and oral amiodarone on morbidity and mortality in patients during the first hours after the onset of an acute myocardial infarction. METHODS AND RESULTS: A cohort of 1073 patients admitted to the CCU within 24 h of the onset of symptoms of an acute myocardial infarction and heart failure (Killip and Kimball A-B) were randomized to receive amiodarone (n=542) or placebo (n=531) for 6 months. Because of the higher mortality, on an interim analysis, from a 'high dose' of amiodarone or placebo (516 patients) the protocol was changed to a 'low dose' or placebo (557 patients). Mortality with high doses of amiodarone was 16.30% vs 10.16% in the placebo group (P=0.04), whereas mortality with low doses was 6.61% vs 9.47% in the control group (P=0.20). Several non-fatal adverse effects were observed in 108 and 73 patients treated with amiodarone and placebo, respectively. CONCLUSION: This study demonstrated that early administration of amiodarone in low doses to patients with an acute myocardial infarction may be used only if life-threatening arrhythmia justify its prescription. Conversely, when given in high doses, it might increase mortality.