Changing characteristics and in-hospital outcome in patients admitted with acute myocardial infarction. Observations from 1982 to 1994.

BACKGROUND: During the past decade, various new treatments have become available for patients with acute myocardial infarction. The effects of these treatment modalities have been studied extensively in selected patient groups. These studies indicate that early diagnosis, risk stratification and prompt initiation of treatment are of crucial importance for optimal benefit. However, it is not known whether prognosis changed in all patients admitted with an acute myocardial infarction. Also, the characteristics of the infarct population may have changed over time because of new medication regimens, invasive interventions and awareness of the importance of risk factors.

METHODS: We studied all patients admitted with acute myocardial infarction in 1982, 1988 and 1994. Information on baseline characteristics, clinical variables and all interventions was collected.

FINDINGS: In those 3 years 223, 227 and 235 patients were admitted because of an acute myocardial infarction. Patients admitted in 1994 were older, more often female and less often had a previous cardiac history. More patients admitted in that year had previous balloon angioplasty and coronary bypass grafting. Smoking habits decreased during the past decade. In-hospital mortality was 38 (17%) in 1982, 23 (10%) in 1988 and 22 (9%) in 1994 (P < 0.05). Variables related to high risk for in-hospital death in 1982 were higher age, low systolic blood pressure, atrial fibrillation, absence of accelerated idioventricular rhythm, sustained ventricular tachycardia and signs of left ventricular dysfunction; in 1988 the occurrence of non-sustained ventricular tachycardia, Killip class more than I, the absence of thrombolytic therapy, percutaneous transluminal coronary angioplasty or coronary artery bypass grafting were independently related to in-hospital death. In 1994, high risk variables for in-hospital death were dyspnoea on admission, sustained ventricular tachycardia, female gender, higher creatinine on admission, and a previous cardiac history.

INTERPRETATION: In-hospital mortality for unselected patients admitted with an acute myocardial infarction decreased between 1982 and 1988 and remained the same between 1988 and 1994, in spite of further ageing of the population. In the study period there has been a change in baseline characteristics and high risk variables for in-hospital death after myocardial infarction.