Beneficial effect of long-term use of a beta-blocker in patients before acute myocardial infarction.

The outcome of 38 beta-blocker users (group BB, 28 men and 10 women with a mean age of 56 +/- 4 years) was compared to that of 100 non-users (group NU, 69 men and 31 women with a mean age of 57 +/- 8 years) after acute myocardial infarction (AMI). The two groups were compared in terms of electrocardiographic (EKG) location of the AMI (anterior, inferior and lateral), EKG Q and non-Q wave infarction, clinical functional class of Forrester, serum creatine phosphokinase MB fraction (CKMB) peak release and intrahospital mortality. There were no differences between groups concerning sex or severity of coronary artery disease but arterial hypertension was 2-fold more prevalent in group BB. The EKG location of the AMI was similar in the two groups. Non-Q infarction was significantly more prevalent in group BB (37%) than in group NU (6%). The incidence of clinical functional class IV of Forrester and the serum CKMB peaks were significantly lower in group BB (2.6% vs 16.0% and 53 +/- 3 vs 68 +/- 9 IU/l, respectively). Intrahospital mortality was also significantly lower in group BB (2.6%) than in group NU (10%). These data suggest the beneficial effect of previous long-term use of beta-blockers as indicated by a lower incidence of cardiogenic shock and a significant decrease in intrahospital mortality after AMI.