What are the risks of recurrent ischaemic events after myocardial infarction?

What are the risks of recurrent ischaemic events after myocardial infarction: prehospital, at 30 days and at 1 year?

Data from the WHO MONICA project in 38 populations from 21 countries show that 49% and 54%, respectively, of all men and women with an acute coronary event die within 28 days.1 About 70% of these deaths occur out of hospital on day 1 and it is generally accepted that a large proportion of these early deaths are the result of ventricular fibrillation. Thus provision of rapid access to a defibrillator remains the single most effective way to save lives in acute coronary syndromes. Following hospital admission the outcome of acute myocardial infarction is determined largely by left ventricular function. Before the introduction of thrombolytic and other reperfusion strategies, average in-hospital mortality from acute myocardial infarction declined from 32% during the 1960s to 18% during the 1980s.2 With the introduction of reperfusion therapy further improvements in the short and long term prognosis of acute myocardial infarction have been confirmed in several large studies comparing cohorts of patients admitted before and after the late 1980s.3,4 Thus, in a group of patients who received CCU treatment for acute myocardial infarction, we reported 30 day and 1 year mortality rates (95% confidence intervals) of 16.0% (13.4–19.2%) and 21.7% (18.6–25.2%), rising to 19.6% (16.6–23.0%) and 33.2% (29.5–37.2%), respectively, when a combined end point of mortality plus non-fatal recurrent events (unstable angina, myocardial infarction) was considered.5 Multivariate predictors of better short term survival included treatment with thrombolysis and aspirin, while predictors of worse survival included left ventricular failure, advanced age and bundle branch block. Whether survival after acute myocardial infarction has continued to improve in the thrombolytic era is unknown although the increasing application of effective secondary prevention strategies provides grounds for optimism.