EARLY INTRAVENOUS ATENOLOL TREATMENT IN SUSPECTED ACUTE MYOCARDIAL INFARCTION Journal Articles uri icon

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abstract

  • All patients suitable for beta blockade entering the coronary care units at Oxford and Manchester were studied in a randomised trial to determine whether administration of intravenous atenolol within 12 hours of chest pain reduced infarct size and ventricular arrythmias.Infarct size was measured using cumulative CKMB release and R wave changes from the standard ECG. The preliminary report on the first 214 patients showed prevention of infarction and a mean one third reduction in infarct size in patients with initial definite infarction (Yusuf et al, 1980).Reanalysis of the data when 400 patients were randomised confirmed the observations of the initial analysis. In patients with initial threatened infarction (n = 143), 59 % of control patients developed infarction compared to 37 % in the atenolol treated patients (2p <0.01). In 247 subjects with initial definite infarction, the percentage of the original R wave remaining was 34.5 ± 8 in the atenolol treated subjects (2 p < 0.0001). In 247 subjects with initial definite infarction, the percentage of the original R wave remaining was 34.5 ± 2.1 in the controls compared to 43.4 ± 2.1 in the atenolol treated patients (2p < 0.003).Although bradycardia and hypotension were commoner in atenolol treated subjects (44 and 23 respectively) compared to controls (18 and 8 respectively), this was easily reversible by stopping the drug or using atropine. Inotropic drugs were only needed in 4 atenolol and 2 control subjects. More control patients needed treatment for heart failure compared to the atenolol group in hospital and at discharge (2p < 0.10 and 2p < 0.05).Ventricular arrythmias were recorded using a 24 hour Medilog recorder in 47 atenolol and 47 control subjects. There was a significant reduction in the incidence of R on T (prematurity index < 1.0) ventricular ectopics (41 % AT v 90 % controls 2p < 0.001), a significant slowing of the rate of sustained ventricular tachycardia (mean 144 in AT v 165 beats / min control 2p < 0.02), a significant delay in the prematurity index of VT (1.70 in AT v 1.34 in controls (2p < 0.01) and coupling interval of VT (680 msec in AT v 503 msec in controls 2p < 0.01).In conclusion, early IV Atenolol decreases infarct size and reduces the incidence and severity of ventricular arrythmias in patients with acute myocardial infarctions. A larger study is required to assess if these physiological benefits lead to a reduction in early and long term mortality.

authors

  • Sleight, Peter
  • Yusuf, Salim
  • Peto, Richard
  • Rossi, Paulo
  • Ramsdale, David
  • Bennett, David
  • Bray, Colin
  • Furse, Lynette

publication date

  • January 12, 1981