Metoprolol-induced reduction in postinfarction mortality: pooled results from five double-blind randomized trials.

Several postinfarction trials have evaluated the effect of secondary prophylaxis with different beta-blockers. Although so called meta-analysis of the results from all the trials have shown a beneficial effect of postinfarction beta-blockade, many of the individual studies have shown inconclusive results, mainly due to low statistical power. In order to obtain an evaluation of the merits of postinfarction therapy with metoprolol, data from the five available studies with metoprolol have been pooled into one database. In the total material 5474 patients (4353 men, 1121 women) have been studied during double-blind therapy with metoprolol 100 mg twice daily or matching placebo. The follow-up ranges from 3 months to 3 years. In total 4732 patient years of observation have been obtained. In total there were 223 deaths in the placebo-treated patients as compared to 188 deaths in the metoprolol-treated patients (P = 0.036), which corresponds to mortality rates of 97.0 and 78.3 per 1000 patient years, respectively. The mortality reduction was found both in men and women. As has been reported from individual postinfarction beta-blocker trials, the pooled results showed a marked reduction in sudden deaths (104 in the placebo group, 62 in the metoprolol group, P = 0.002). In a Cox regression model the influence of sex, age and smoking habits on the effect of metoprolol was evaluated. None of these factors influenced the metoprolol effect significantly. It is concluded that metoprolol therapy after acute myocardial infarction reduces the total number of deaths, and especially sudden cardiac deaths. The mortality reduction was independent of gender, age and smoking habits. Available data support a continuous beneficial effect.

Dobutamine therapy in acute myocardial infarction.

The short-term response of combined dopamine hydrochloride-sodium nitroprusside therapy was compared with administration of dobutamine in eight patients with acute myocardial infarction complicated by hypotension and severe left ventricular dysfunction. All patients were receiving dopamine before the study began. The addition of sodium nitroprusside increased cardiac index (Cl) from 1.94 +/- 0.490 to 2.22 +/- 0.48 L/min/sq m; decreased left ventricular filling pressure (LVFP) from 28.9 +/- 3.5 to 19.9 +/- 3.3 mm Hg and mean systemic arterial pressure (MAP) from 82.1 +/- 5.1 to 71.5 +/- 6.0 mm Hg. During dobutamine infusion, Cl, LVFP, and MAP were 2.33 +/- 0.31 L/min/sq m, 20.8 +/- 4.8 mm Hg, and 74.1 +/- 8.1 mm Hg, respectively. There was no statistical difference between short-term hemodynamic benefits produced by dobutamine or combined dopamine-sodium nitroprusside therapy. Dobutamine, a synthetic cathecholamine, provides a substitute for dopamine-sodium nitroprusside therapy in acute myocardial infarction. Dobutamine has the advantage of being a single agent and is therefore easier to administer.