RESUMO
The effect of intravenous atenolol on ventricular arrhythmias in acute myocardial infarction was assessed in 182 patients admitted within 12 hours of the onset of chest pain. Ninety-five patients were randomised to receive 5 mg intravenous atenolol followed immediately by 50 mg by mouth and 50 mg 12 hours later, then 100 mg daily for 10 days; 87 patients served as controls. The treated patients had significantly fewer ventricular extrasystoles; 58 control patients (67%) had R-on-T extrasystoles compared with only 25 treated patients (26%) (2p less than 0.0001); repetitive ventricular arrhythmias were detected in 64 control patients (74%) and 55 treated patients (58%) (2p less than 0.05). Heart rate was significantly reduced from 77 +/- 1 beats/min at entry to 65 +/- 1 beats/min (2p less than 0.001) in the first hour after intravenous atenolol, and in addition the rate was significantly different from that in the control group. There was no difference in the incidence of heart failure, but fewer patients in the treated group received other antiarrhythmic agents or digoxin. These results show that early intravenous atenolol prevents ventricular arrhythmias in suspected acute myocardial infarction.
Assuntos
Arritmias Cardíacas/prevenção & controle , Atenolol/uso terapêutico , Infarto do Miocárdio/complicações , Propanolaminas/uso terapêutico , Adulto , Idoso , Arritmias Cardíacas/etiologia , Atenolol/administração & dosagem , Complexos Cardíacos Prematuros/prevenção & controle , Ensaios Clínicos como Assunto , Eletrocardiografia , Feminino , Frequência Cardíaca , Ventrículos do Coração , Humanos , Injeções Intravenosas , Masculino , Pessoa de Meia-Idade , Distribuição AleatóriaRESUMO
Four hundred seventy-seven patients suspected of having had acute myocardial infarction within less than 12 hours were randomized to receive i.v. atenolol followed by oral treatment for 10 days or to a control group. In patients with ECG changes indicative of infarction at entry, i.v. atenolol significantly reduced enzyme release by one-third and enhanced R-wave preservation. In patients without such ECG changes, treatment significantly prevented the development of infarction in a proportion of patients. There was also a significant reduction in R-on-T ectopics, repetitive ventricular arrhythmias and supraventricular arrhythmias. Treated patients had significantly greater pain relief and required fewer opiate analgesics. Significantly fewer atenolol-treated patients died by 10 days (the treatment period), had nonfatal cardiac arrests, developed heart failure, or suffered reinfarction.