1-25
1-25. ANGINA PECTORIS
a. Angina pectoris is a clinical syndrome of ischemic heart disease, manifested by paroxysmal pain in the chest and adjacent areas. This disorder is considered to be an early warning of CV deterioration. The symptoms occur as a result of myocardial oxygen demand that exceeds the ability of the coronary arteries to deliver oxygen. (The coronary arteries supply the myocardium with the oxygenated blood it needs to work effectively.) The main cause for this inability to meet oxygen demand is the presence of aterosclerosis that causes advanced occlusion or stenosis of one or more of the three major branches of the coronary artery tree. The coronary arteries are illustrated in Figure 1-3.
b. When the heart is stressed, it must rely on increased coronary blood flow to meet the increased oxygen demand of the cardiac tissue. Coronary blood flow is determined by the amount of pressure in the aorta and the amount of resistance in the coronary arteries. If atherosclerosis is present in the coronary vascular system, coronary blood flow is decreased because of the increased resistance in the coronary arteries.
c. The pain of angina pectoris occurs when the heart is stressed or worked to a point where the oxygen demand is greater than the amount of oxygen that can be delivered. This usually occurs with some type of exertion, such as mowing the lawn, climbing stairs, or doing heavy housework. In the affected patient, the onset of pain will occur with exertion, and relief will normally occur with rest. Rest will decrease the workload on the heart, thereby decreasing the heart's oxygen demand and relieving the pain.
d. Unstable angina pectoris is a term used to describe the exacerbation of the symptoms of angina pectoris. This syndrome is characterized by increased severity of symptoms, increased ease in provoking attacks of
angina, and less predictability in controlling angina attacks. Symptoms may be severe enough to mimic an acute myocardial infarction. Crescendo angina and acute coronary insufficiency are also terms used to describe unstable angina.
e. In either case, medical management is the same. The patient is educated about the nature of the disease so that it may be controlled with diet, medication, exercise, and risk factor modification. When the condition advances to the stage where it can no longer be controlled in this manner, surgical intervention may be indicated. Two surgical possibilities include the coronary artery bypass graft (CABG) and transluminal coronary angioplasty (balloon compression).
