Angina is pain, discomfort, or pressure in the chest that is caused by ischemia, an insufficient supply of oxygen-rich blood to the heart muscle. It is sometimes also characterized by a feeling of choking, suffocation, or crushing heaviness. This condition is also called angina pectoris.
Often described as a muscle spasm and choking sensation, the term angina is used primarily to describe chest (thoracic) pain caused by insufficient oxygen to the heart muscle. An episode of angina is not an actual heart attack, but rather pain that results when the heart muscle temporarily receives too little blood. This temporary condition may be the result of demanding activities such as exercise and does not necessarily indicate that the heart muscle is experiencing permanent damage. In fact, episodes of angina seldom cause permanent damage to heart muscle.
Angina can be subdivided into two categories: angina of effort and variant angina.
Angina of effort
Angina of effort is a common disorder caused by the narrowing of the arteries (a condition called atherosclerosis)
Variant angina is uncommon and occurs independently of atherosclerosis, which may incidentally be present. Variant angina occurs at rest and is not related to excessive work by the heart muscle. Research indicates that variant angina is caused by coronary artery muscle spasm that does not last long enough or is not intense enough to cause an actual heart attack.
Causes & symptoms
Angina is usually caused by an underlying obstruction to the coronary artery due to atherosclerosis. In some cases, it is caused by spasm that occurs naturally or as a result of ingesting cocaine. In rare cases, angina is caused by a coronary embolism or by a disease other than atherosclerosis that places demands on the heart.
Most episodes of angina are brought on by physical exertion, when the heart needs more oxygen than is available from the blood nourishing the heart. Emotional stress, extreme temperatures, heavy meals, cigarette smoking, and alcohol can also cause or contribute to an episode of angina.
Angina causes a pressing pain or sensation of heaviness, usually in the chest area under the breast bone (sternum). It is occasionally experienced in the shoulder, arm, neck, or jaw regions. In most cases, the symptoms are relieved within a few minutes by resting or by taking prescribed angina medications.
Physicians can usually diagnose angina based on the patient's symptoms and the precipitating factors. However, other diagnostic testing is often required to confirm or rule out angina, or to determine the severity of the underlying heart disease.
An electrocardiogram is a test that records electrical impulses from the heart. The resulting graph of electrical activity can show if the heart muscle isn't functioning properly as a result of a lack of oxygen. Electrocardiograms are also useful in investigating other possible abnormal features of the heart, such as arrhythmia (irregular heartbeat).
For many individuals with angina, the results of an electrocardiogram while at rest will not show any abnormalities. Because the symptoms of angina occur during stress, the heart's function may need to be evaluated under the physical stress of exercise. The stress test records information from the electrocardiogram before, during, and after exercise in search of stress-related abnormalities. Blood pressure is also measured during the stress test and symptoms are noted. In some cases a more involved and complex stress test (for example, thallium scanning) is used to picture the blood flow in the heart muscle during the most intense exercise and after rest.
The angiogram, which is a series of x rays of the coronary artery, has been noted as the most accurate diagnostic test to indicate the presence and extent of coronary disease. In this procedure, a long, thin, flexible tube (catheter) is inserted into an artery located in the forearm or groin. This catheter is passed further through the artery into one of the two major coronary arteries. A dye is injected through the catheter to make the heart, arteries, and blood flow clearer on the x ray. A fluoroscopic film, or series of "moving" x rays, shows the blood flowing through the coronary arteries. This will reveal any possible narrowing that can cause a decrease in blood flow to the heart muscle and associated symptoms of angina.
Controlling existing factors that place the individual at risk is the first step in addressing artery disease that causes angina. These risk factors include cigarette smoking, high blood pressure, high cholesterol levels, and obesity.
Once the angina has subsided, the cause should be determined and treated. Atherosclerosis, a major associated cause, requires diet and lifestyle adjustments, primarily including regular exercise, reduction of dietary sugar and saturated fats, and increase of dietary fiber.
In recent years, several specific cholesterol-lowering treatments have gained the attention and interest of the public. One of the most recent popular treatments is garlic (Allium sativum). Some studies have shown that garlic can reduce total cholesterol by about 10% and LDL (bad) cholesterol by 15%, and can raise HDL (good) cholesterol by
A 1999 study published in the American Journal of Clinical Nutrition found that red yeast extract can significantly reduce cholesterol when it's taken in conjunction with a low-fat diet. Red yeast extract, available in the United States under the trade name Cholestin, has been used in Chinese medicine to treat heart maladies for hundreds of years. The effectiveness of the extract depends on the patient's cholesterol level and medical history, so individuals should consult with their healthcare professionals before taking the supplement. Additional herbal remedies that may help lower cholesterol include oats (Avena sativa), alfalfa (Medicago sativa), fenugreek (Trigonella foenumgraecum), Korean ginseng (Panax ginseng), myrrh (Commiphora molmol), and turmeric (Curcuma longa).
Yarrow (Achillea millefolium), linden (Tilia europaea), and hawthorn (Crataegus spp.) are sometimes recommended for controlling high blood pressure, a risk factor for heart disease. In particular, hawthorn extract appears to benefit the aging heart. A 2001 report of a European study reported that patients using hawthorn extract showed improvements in exercise tolerance, fatigue, and shortness of breath.
Tea (Camellia sinensis)—especially green tea—is high in antioxidants, and studies have shown that it may help prevent atherosclerosis. Other antioxidants, including vitamin A (beta carotene), vitamin C, vitamin E, and selenium, can also limit the damage to the walls of blood vessels by oxidation, which may be lead to the formation of atherosclerotic plaque.
Vitamin and mineral supplements that reduce, reverse, or protect against coronary artery disease include chromium, calcium and magnesium, B-complex vitamins, L-carnitine, and zinc. Yoga and other bodywork, massage, aromatherapy, and music therapy may also help reduce angina symptoms by promoting relaxation and stress reduction.
Traditional Chinese medicine may recommend herbal remedies (such as a ginseng and aconite combination), massage, acupuncture, and dietary modification. Exercise and a healthy diet, including cold-water fish as a source of essential fatty acids, are important components of a regimen to prevent angina and heart disease.
Angina is often controlled by medication, most commonly with nitroglycerin. This drug relieves symptoms of angina by increasing the diameter of the blood vessels that carry blood to the heart muscle. Nitroglycerin is taken whenever discomfort occurs or is expected. It may be taken sublingually, by placing the tablet under the tongue. Or it may be administered transdermally, by placing a medicated patch directly on the skin.
In addition, beta-blockers or calcium channel blockers may be prescribed to decrease the heart's rate and workload. In late 2001, a study reported that the drug Nicorandil had become the first to demonstrate a reduction in risk of angina and to improve symptoms in patients with chronic stable angina. Guidelines released late in 2000 promoted use of lopidogrel to help prevent recurring events. A study group that used clopidogrel and aspirin showed a significant decrease in cardiovascular death, nonfatal heart attack, and stroke compared to patients in a control group that received a placebo and aspirin.
When conservative treatments are not effective in reducing angina pain and the risk of heart attack remains high, physicians may recommend angioplasty or surgery. In coronary artery bypass surgery, a blood vessel (often a long vein surgically removed from the leg) is grafted onto the blocked artery to bypass the blocked portion. This newly formed pathway allows blood to flow adequately to the heart muscle.
Another procedure used to improve blood flow to the heart is percutaneous tranluminal coronary angioplasty, usually called coronary or balloon angioplasty. In this procedure, the physician inserts a catheter with a tiny balloon at the end into a forearm or groin artery. The catheter is then threaded up into the coronary arteries, and the balloon is inflated to open the vessel in narrowed sections. Other techniques to open clogged arteries are under development and in limited use, including the use of lasers, stents, and other surgical devices.
The prognosis for a patient with angina depends on the general health of the individual as well as on the origin, type, and severity of the condition. A person can improve his or her prognosis by seeking prompt medical attention and learning the pattern of his or her angina, such as what causes the attacks, what they feel like, how long episodes usually last, and whether medication relieves the attacks. Medical help should be sought immediately if patterns of the symptoms change significantly or if symptoms resemble those of a heart attack.
In most cases, the best prevention involves changing habits to avoid bringing on attacks of angina. A hearthealthy
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American Heart Association. National Center. 7272 Greenville Avenue, Dallas, Texas 75231. (800) AHA-USA1. <http://www.americanheart.org>.
National Heart, Lung, and Blood Institute Information Center. P.O. Box 30105, Bethesda, MD 20824. (301) 251-1222. <http://www.nhlbi.nih.gov/health/infoctr/index.htm>.
Teresa G. Odle