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Causes and Incidence Angina is caused by an imbalance in the demand for oxygen and the myocardial oxygen supply. Coronary atherosclerosis is often an underlying factor. Aortic stenosis, hypertension, and cardiomyopathy can also play a role.

Disease Process In the usual pathogenic process, atherosclerosis eventually causes an obstruction, which leads to diminution of the coronary blood flow, which in turn reduces the myocardial oxygen supply and delivery. An increase in oxygen demand through exertion, exercise, or an underlying pathologic condition causes oxygen demand to outstrip supply, and pain results.

Symptoms The chief symptom is a highly variable, transient, substernal pain that typically arises with exertion (exercise, heavy meal, emotional excitement, sexual intercourse) and subsides with rest. It may be a vague ache or an intense crushing sensation that may or may not radiate to the left shoulder, arm, or jaw or through to the back. Attacks are exacerbated by cold. Because characteristics tend to be constant for a given individual, a change in symptom patterns (e.g., an increase in the frequency or intensity of attacks) should be viewed as serious. When these changes occur, the condition is called unstable angina.

Potential Complications Angina, particularly unstable angina, is often a precursor to myocardial infarction (MI).

Diagnostic Tests The chief diagnostic parameters are (1) clinical evaluation of the nature of the pain; (2) the type of electrocardiographic changes seen during an attack; and (3) whether the pain is relieved promptly by a test dose of nitroglycerin.

Treatments

Surgery

Coronary artery bypass for selected cases with severe angina, localized coronary artery disease (CAD), no history of MI, and good ventricular function; angioplasty to remove obstructive atherosclerotic lesion

Drugs

Nitrates, betablockers, and calcium antagonists to prevent myocardial insufficiency and relieve pain; prophylactic aspirin in daily doses for individuals with known CAD; heparin to treat intracoronary clotting in cases of unstable angina

General

Reduction of risk behaviors (e.g., smoking); diet to reduce cholesterol levels and/or weight if necessary; consistent exercise program