angina pectoris (redirected from unstable angina)

angina pectoris (ănjī`nə pĕk`tərĭs), condition characterized by chest pain that occurs when the muscles of the heart receive an insufficient supply of oxygen. This results when the arteries that supply the heart muscle with oxygenated blood are narrowed by arteriosclerosis. In rare cases angina results from spasms of the coronary arteries. Angina is a primary symptom of coronary artery disease.

The pain is usually experienced under or to the left of the sternum (breastbone) and radiates to the left shoulder and down the upper arm; less frequently, it spreads to the right shoulder. The attack usually subsides without residual discomfort and, when precipitated by physical exertion, is quickly halted when the subject rests. Often the attacks are separated by weeks, months, even years in which symptoms subside. Symptoms usually begin after the age of 50, more often in men than women, and frequently follow physical exertion, excitement, eating, smoking, or exposure to cold. Associated symptoms are faintness and difficulty in breathing.

Nitrates (e.g., amyl nitrite or nitroglycerin), drugs that dilate the blood vessels of the heart, are traditionally used in treatment. Newer drug treatments include beta-blockers and calcium-channel blockers. Significant narrowing of the coronary arteries may require surgical treatment, such as a coronary artery bypass, a procedure that splices healthy blood vessels taken from elsewhere in the body to the affected coronary arteries in such a way that the clogged areas are bypassed. In angioplasty, a balloon-tipped catheter is inserted through the skin into a blood vessel and maneuvered to the clogged artery. There it is threaded into the blockage and inflated, compressing the plaque against the arterial walls. New techniques use atherotomes to mechanically cut the plaque or cold lasers to remove plaque with bursts of ultraviolet light.

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angina pectoris

Spasm of chest pain, caused when the heart's oxygen demand temporarily outpaces its blood supply, usually because of coronary heart disease. A deep, viselike pain in the heart and stomach area commonly spreads to the left arm. Exertion or emotional stress can bring on angina, obliging the victim to rest until the pain subsides. If rest does not help, drugs can dilate the blood vessels. As heart disease worsens, angina recurs with less exertion.