The Medical Therapy of Angina Pectoris

Since the first published observations of occluded coronary arteries by Morgagni in 1761,' and the classic description of angina pectoris by William Heberden, as presented to the Royal College of physicians in 1768,̂ the medical treatment of angina has demonstrated a surprising lack of diversity, Heberden was able to effect temporary relief with opiates, but noted no beneficial response to wine, spirits, or bloodletting,^ In 1867, nitrates were first used specifically for angina, in the form of amyl nitrite, by Thomas Lauder Brunton,"* thus initiating the form of pharmacologic intervention that has persisted as the major form of therapy to the present day. Angina pectoris is the discomfort that occurs as a manifestation of myocardial ischemia. The typical characteristics include: (1) location over the sternum or very near it; (2) radiation to the jaw, left shoulder, or arm; (3) a feeling of pressure, burning, or tightness; (4) precipitation by exertion, cold, or emotional distress; (5) duration of 30 seconds to 30 minutes; and (6) relief in 45 seconds to 5 minutes following the use of nitroglycerin. The clinical syndrome of angina pectoris is not a diagnostic endpoint, however, since several cardiac disorders other than atherosclerotic cardiovascular disease are well-known to incorporate symptoms of angina. Important examples of these included aortic stenosis or regurgitation, hypertrophic cardiomyopathy (IHSS), and reversible coronary vasospasm (Prinzmetal's angina). Angina is classified as either stable or unstable, although the medical therapy of the former will be the major focus ofthis review. Unstable angina (also known as pre-infarction or crescendo angina) is typified by the presence of angina pectoris involving at least one of the following patterns: (1) angina of new onset, brought on by minimal exertion; (2) the development of more severe, prolonged, or frequent angina occurring in the