Coronary heart disease is the most frequent cause of death in Western, industrialized countries. Coronary risk factors are prevalent in such countries and sometimes combine to constitute the so-called syndrome X--
hypertension,
central obesity, serum
lipid and clotting disturbances, and
insulin resistance. beta-Blockers, unlike
calcium antagonists, have proved highly effective in
secondary prevention of
myocardial infarction. If present at the time of the
myocardial infarction, beta-blockers (unlike
calcium antagonists and
diuretics) probably decrease mortality 1 month later. Early intervention (within 12 h) of
chest pain with intravenous beta-blockers results in a 15% reduction in cardiovascular mortality at 1 week. Later intervention (3-28 days) with oral non-ISA beta-blockers results in a 30% reduction in mortality after 1 year; ISA-containing beta-blockers are probably less effective (less decrease in heart rate). Hydrophilicity/lipophilicity of beta-blockers is unimportant in terms of decreased mortality. Primary prevention of
myocardial infarction, unlike
stroke, in hypertensive patients has been disappointing, possibly due to treatment-induced biochemical/
lipid changes or inappropriate lowering of diastolic blood pressure in high-risk subjects (J-curve effect). beta-Blockers should be first-line
therapy for hypertensive patients up to the age of 65 years, particularly men (and nonsmokers) as Q-wave
myocardial infarction is significantly decreased by beta-blockers and significantly increased by
diuretics. However, in elderly hypertensive subjects, beta-blockers have not significantly decreased
myocardial infarction (unlike
stroke), whereas
diuretics have. The effects of beta-blockers and
diuretics on heart size (and thus coronary flow reserve) in the elderly may be important. Thus, beta-blockers should be second-line
therapy for the elderly hypertensive individual but first-line if overt
ischemia (e.g., angina or recent
myocardial infarction) also is present. In patients with angina but normal blood pressure, beta-blockers tend to decrease and
calcium antagonists increase cardiovascular events. Thus, beta-blockers are highly effective agents in the
secondary prevention of
myocardial infarction and are moderately effective in primary prevention of
myocardial infarction in hypertensive patients (particularly men) under the age of 65 years.