[Has the prognosis of recent myocardial infarction changed?]

In this retrospective study changes in the prognosis of recent myocardial infarction were evaluated by comparing 731 patients hospitalized in the 1970-1974 period (group I) with 755 patients hospitalized in the 1984-1986 period (group II). The possible factors responsible for the changes observed were investigated. A 34 percent decrease in hospital mortality was recorded (19.2% in group I versus 12.6% in group II; P less than 0.001). The decrease was present irrespective of the patients' sexes and ages; it was more pronounced in patients under 65 (-42%) and in elderly women (-43%). Compared with group I patients, group II patients showed a significant decrease in cardiogenic shock (P less than 0.02), atrial fibrillation (P less than 0.05) and, chiefly, atrioventricular block (P less than 0.001). The improvement in prognosis cannot be ascribed to a change of population since both groups were matched in male to female ratio, age distribution and presence of the main risk factors. Three factors may have contributed to a better prognosis: (1) more rapid admission to hospital; the proportion of patients admitted within 6 hours of the initial symptoms rose from 37.5% in group I to 49.8% in group II (P less than 0.001); (2) modification of the conventional treatment, with a reduced prescription of digitalis and a less frequent recourse to temporary electrical pacing; (3) introduction of new treatments aimed at limiting the size of the necrotic area; these include thrombolytic agents which were administered in 19.2% of patients under 65 and may well have played the principal role in the improvement of outcome.