Angina pectoris is pain in the chest that is the result of insufficient oxygen being carried to the heart muscle in the blood. The pain of angina pectoris usually occurs when the heart is working harder and requires more oxygen, such as during exercise or at times of stress.
Inadequate blood supply to the heart is usually due to coronary artery disease, in which the coronary arteries are narrowed by atherosclerosis (fat deposits on the artery walls). Other causes include coronary artery spasm, in which the blood vessels narrow suddenly for a short time, aortic stenosis, in which the heart’s aortic valve is narrowed, and arrhythmias(abnormal heart rhythms).The pain of angina pectoris is brought on by exertion and is relieved by rest. If the pain continues, it may be due to a heart attack (see myocardial infarction). Rarer causes of the pain include severe anaemia, which reduces the blood’s oxygen-carrying efficiency, and polycythaemia, which thickens the blood and causes its flow through the heart muscle to slow down.
The chest pain of angina varies from mild to severe and is often described as a sensation of pressure on the chest. The pain usually starts in the centre of the chest but can spread to the throat, upper jaw, back, and arms (usually the left), or between the shoulder blades. If it develops during sleep or without provocation, it is called unstable angina. Other possible symptoms of angina pectoris include nausea, sweating, dizziness, and breathing difficulty.
Diagnosis and treatment
Diagnostic tests usually include an ECG (measurement of the electrical activity of the heart), which may register normal between attacks, and a cardiac stress test (an ECG undertaken while the patient is exercising enough to cause chest pain). Blood tests and coronary angiography (X-ray examination of the blood vessels) may also be performed to look for an underlying cause. To help to control the symptoms of angina pectoris, it is important for the person to stop smoking and to lose weight if necessary. Attacks may be prevented and treated by nitrate drugs, which increase blood flow through the heart muscle.Beta-blocker drugs, calcium channel blockers, lipid-lowering drugs, and antiplatelet drugsmay also be prescribed. Drug treatment can control the symptoms for many years but cannot cure the disorder. If attacks become more severe or more frequent, despite treatment,coronary artery bypass surgery or angioplasty may be necessary.
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