Beta Receptor Blocking Agents in the Secondary Prevention of Coronary Heart Disease

In the western world coronary heart disease (CHD) constitutes the single most common cause of death from middle age on in both men and women (1). This fact remains despite a recent decline in mortality from the disease in some countries including the USA (2). The magnitude of the problem has induced planning and realization of a number of trials aimed at reducing mortality and new events. The natural history of CHD is usually divided into two major parts separated by the initial manifestation of the disease. During the period preceding the initial clinical manifestation certain factors have been found to be statistically significantly associated with increased risk of an initial event, i.e. primary risk factors. Measures aimed at these factors are usually included under a common heading, primary prevention. In an analogous way factors associated with increased risk of a second or further events are termed secondary risk factors, and measures aimed at a reduction of these late complications are grouped under the heading secondary prevention. Coronary heart disease has three major clinical manifestations: angina pec­ toris, acute myocardial infarction, and sudden cardiac death, listed in as­ cending order of clinical urgency. Despite widespread availability of cardiopulmonary resuscitation, in some areas few victims of sudden cardiac death had been exposed to secondary prevention, and for a number of reasons, despite the high prevalence of the symptom, there have been very few systematic studies or controlled trials of secondary prevention in angina pectoris. An acute myocardial infarction constitutes a clinical �vent that defines a subcategory of the population that, in addition to be�ng easy to find, has