Angina Pectoris
Webpages concerning "Angina Pectoris"
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Wikipedia-Article "Angina Pectoris"
| Angina | ||
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| ICD-10 code: | I20 | |
| ICD-9 code: | 413 | |
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This is about chest pain due to oxygen shortage in the heart. For angina tonsillaris see tonsillitis.
Angina pectoris is chest pain due to ischemia (a lack of blood and hence oxygen supply) to the heart muscle, generally due to obstruction or spasm of the coronary arteries (the heart's blood vessels). Coronary artery disease, the main cause of angina, is due to atherosclerosis of the cardiac arteries. The term derives from the Greek ankhon ("strangling") and the Latin pectus ("chest"), and can therefore be translated as "a strangling feeling in the chest".
Worsening ("crescendo") angina attacks, sudden-onset angina at rest, and angina lasting more than 15 minutes are symptoms of unstable angina or acute coronary syndrome. As these may herald myocardial infarction (a heart attack), they require urgent medical attention and are generally treated quite similarly.
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Symptoms
Most patients with angina complain of chest discomfort rather than actual pain, the discomfort is usually described as a pressure, heaviness, squeezing, burning, or choking sensation. Anginal pain may be localized primarily in the epigastrium (upper central abdomen), back, neck, jaw, or shoulders. Typical locations for radiation of pain are arms, shoulders, and neck. Angina typically is precipitated by exertion or emotional stress, and exacerbated by having a full stomach or cold temperatures (the "4 Es": exertion, emotion, eating and extreme temperature). Pain may be accompanied by sweating and nausea in some cases. It usually lasts for about 1 to 5 minutes, and is relieved by rest or specific anti-angina medication. Chest pain lasting only a few seconds is normally not angina.
Some experience "autonomic symptoms" (related to increased activity of the autonomic nervous system) such as nausea, vomiting and pallor.
Major risk factors for angina include family history of premature heart disease, cigarette smoking, diabetes, high cholesterol, and high blood pressure.
A variant form of angina (Prinzmetal's angina) occurs in patients with normal coronary arteries or insignificant atherosclerosis. It is thought to be caused by spasms of the artery. It occurs more in younger women.
Diagnosis
In patients with occasional angina who are not having chest pain, an electrocardiogram (ECG) is typically normal, unless there have been other cardiac problems in the past. During pain, depression or elevation of the ST segment may be observed. To elicit these changes, an exercise ECG test ("treadmill test") may be performed, during which the patient exercises to the point that the pain occurs; if the ECG changes are documented, the test is considered diagnostic for angina. Other alternatives include a thallium scintigram (in patients that cannot exert enough for the purposes of the treadmill tests, e.g., due to asthma or arthritis).
In patients in whom noninvasive testing is diagnostic, a coronary angiogram is typically performed to identify the nature of the coronary lesion, and whether this would be a candidate for angioplasty, coronary artery bypass graft (CABG) or other treatments.
Pathophysiology
Increases in heart rate result in increased oxygen demand by the heart. The heart has a limited ability to increase its oxygen intake during episodes of increased demand. Therefore, an increase in oxygen demand by the heart (e.g., during exercise) has to be met by a proportional increase in blood flow to the heart.
Myocardial ischemia can result from:
- a reduction of blood flow to the heart caused by the stenosis or spasm of the heart's arteries
- resistance of the blood vessels
- reduced oxygen-carrying capacity of the blood.
Atherosclerosis (narrowing of the blood vessels) is the most common cause of stenosis of the heart's arteries and, hence, angina pectoris.
Many people with chest pain have normal or minimal narrowing of heart arteries. This has shown that resistance of the blood vessels (abnormal constriction or deficient relaxation of heart vessels) can be responsible for as much as 95% of coronary artery resistance.
Myocardial ischemia also can be the result of factors affecting blood composition, such as reduced oxygen-carrying capacity of blood, as seen with severe anemia (low number of red blood cells), or long-term smoking.
Epidemiology
Roughly 6.3 million Americans are estimated to experience angina. Angina is more often the presenting symptom of coronary artery disease in women than in men. The prevalence of angina rises with an increase in age. Similar figures apply in the remainder of the Western world. All forms of coronary heart disease are much less-common in the Third World, as its risk factors are much more-common in Western and Westernized countries; it could therefore be termed a disease of affluence. The increase of smoking, obesity and other risk factors has already led to an increase in angina and related diseases in countries such as China.
Treatment
The main goals of treatment in angina pectoris are relief of symptoms, slowing progression of the disease, and reduction of future events, especially heart attacks. An aspirin (75 mg to 100 mg) per day has been shown to be beneficial for all patients with stable angina that have no problems with its use. Beta-blockers and nitroglycerin medication are used for symptomatic relief of angina and prevention of ischemic events, and calcium channel blockers (such as verapamil).
Identifying and treating risk factors of coronary heart disease is a priority in patients with angina. This means testing for elevated cholesterol, diabetes, hypertension (high blood pressure), stopping smoking and losing weight.
Unstable angina
Physicians distinguish between stable angina, which occurs during exercise or stress, and is relieved with a nitrate spray or tablet (e.g., amyl nitrite), and unstable angina, which occurs at rest, or is unrelieved by the usual medication. A patient with angina that is increasing in frequency or severity is also said to have unstable angina.
Unstable angina is very predictive of a heart attack, and requires immediate medical attention. As it is only one of the many potential causes of chest pain, the patient usually has a number of tests in the emergency department, such as a chest X-ray, blood tests (including myocardial markers such as troponin I or T, and a D-dimer if a pulmonary embolism is suspected) and telemetry (monitoring of the heart rhythm).
If the ECG does not show the changes (ST elevation) typical of myocardial infarction (heart attack), the patient may still have suffered a "non-ST elevation MI" (NSTEMI). The accepted management of unstable angina and acute coronary syndrome is therefore empirical treatment with aspirin, heparin (usually a low molecular weight heparin such as enoxaparin), clopidogrel, and intravenous glyceryl trinitrate if the pain persists. A blood test is generally performed for cardiac troponins twelve hours after onset of the pain. If this is positive, coronary angiography is typically performed on an urgent basis, as this is highly predictive of a heart attack in the near-future. If the troponin is negative, a treatmill exercise test or a thallium scintigram may be requested.