angina

Angina

Definition

Angina is pain, "discomfort," or pressure localized in the chest that is caused by an insufficient supply of blood (ischemia) to the heart muscle. It is also sometimes characterized by a feeling of choking, suffocation, or crushing heaviness. This condition is also called angina pectoris.

Description

Often described as a muscle spasm and choking sensation, the term "angina" is used primarily to describe chest (thoracic) pain originating from insufficient oxygen to the heart muscle. An episode of angina is not an actual heart attack, but rather pain that results from the heart muscle temporarily receiving 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 further 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 (atherosclerosis) that supply oxygen-rich blood to the heart muscle. In the case of angina of effort, the heart (coronary) arteries can provide the heart muscle (myocardium) adequate blood during rest but not during periods of exercise, stress, or excitement—any of which may precipitate pain. The pain is relieved by resting or by administering nitroglycerin, a medication that reduces ischemia of the heart. Patients with angina of effort have an increased risk of heart attack (myocardial infarction).

Variant angina

Variant angina is uncommon and occurs independently of atherosclerosis which may, however, be present as an incidental finding. 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 of insufficient duration or intensity to cause an actual heart attack.

Causes and symptoms

Angina causes a pressing pain or sensation of heaviness, usually in the chest area under the breast bone (sternum). It occasionally is experienced in the shoulder, arm, neck, or jaw regions. Because episodes of angina occur when the heart's need for oxygen increases beyond the oxygen available from the blood nourishing the heart, the condition is often precipitated by physical exertion. In most cases, the symptoms are relieved within a few minutes by resting or by taking prescribed angina medications. Emotional stress, extreme temperatures, heavy meals, cigarette smoking, and alcohol can also cause or contribute to an episode of angina.

Diagnosis

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.

Electrocardiogram (ecg)

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.

Stress test

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 functioning of the heart 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. A more involved and complex stress test (for example, thallium scanning) may be used in some cases to picture the blood flow in the heart muscle during the most intense time of exercise and after rest.

Angiogram

The angiogram, which is basically an x ray of the coronary artery, has been noted to be the most accurate diagnostic test to indicate the presence and extent of coronary disease. In this procedure, a long, thin, flexible tube (catheter) is maneuvered 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 at that time to help the x rays "see" the heart and arteries more clearly. Many brief x rays are made to create a "movie" of blood flowing through the coronary arteries, which will reveal any possible narrowing that causes a decrease in blood flow to the heart muscle and associated symptoms of angina.

Treatment

Conservative treatment

Artery disease causing angina is addressed initially by controlling existing factors placing the individual at risk. These risk factors include cigarette smoking, high blood pressure, high cholesterol levels, and obesity. Angina is often controlled by medication, most commonly with nitroglycerin. This drug relieves symptoms of angina by increasing the diameter of the blood vessels carrying blood to the heart muscle. Nitroglycerin is taken whenever discomfort occurs or is expected. It may be taken by mouth by placing the tablet under the tongue or transdermally by placing a medicated patch directly on the skin. In addition, beta blockers or calcium channel blockers may be prescribed to also decrease the demand on the heart by decreasing the rate and workload of the heart.

Surgical treatment

When conservative treatments are not effective in the reduction of angina pain and the risk of heart attack remains high, physicians may recommend angioplasty or surgery. Coronary artery bypass surgery is an operation in which 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.

Key terms

Ischemia — Decreased blood supply to an organ or body part, often resulting in pain.Myocardial infarction — A blockage of a coronary artery that cuts off the blood supply to part of the heart. In most cases, the blockage is caused by fatty deposits.Myocardium — The thick middle layer of the heart that forms the bulk of the heart wall and contracts as the organ beats.Another procedure used to improve blood flow to the heart is 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 using laser and mechanical devices are being developed and applied, also by means of catheters.

Alternative treatment

During an angina episode, relief has been noted by applying massage or kinesiological methods, but these techniques are not standard recommendations by physicians. For example, one technique places the palm and fingers of either hand on the forehead while simultaneously firmly massaging the sternum (breast bone) up and down its entire length using the other hand. This is followed by additional massaging by the fingertip and thumb next to the sternum, on each side.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. Both conventional and alternative medicine agree that increasing exercise and improving diet are important steps to reduce high cholesterol levels. Alternative medicine has proposed specific cholesterol-lowering treatments, with several gaining the attention and interest of the public. One of the most recent popular treatments is garlic (Allium sativum). Some studies have shown that adequate dosages of garlic can reduce total cholesterol by about 10%, LDL (bad) cholesterol by 15%, and raise HDL (good) cholesterol by 10%. Other studies have not shown significant benefit. Although its effect on cholesterol is not as great as that achieved by medications, garlic may possibly be of benefit in relatively mild cases of high cholesterol, without causing the side effects associated with cholesterol-reducing drugs. Other herbal remedies that may help lower cholesterol include alfalfa (Medicago sativa), fenugreek (Trigonella foenum-graecum), Asian ginseng (Panax ginseng), and tumeric (Curcuma longa).Antioxidants, including vitamin A (beta carotene), vitamin C, vitamin E, and selenium, can limit the oxidative damage to the walls of blood vessels that may be a precursor of atherosclerotic plaque formation.

Prognosis

The prognosis for a patient with angina depends on its origin, type, severity, and the general health of the individual. A person who has angina has the best prognosis if he or she seeks prompt medical attention and learns 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. If patterns of the symptoms change significantly, or if symptoms resemble those of a heart attack, medical help should be sought immediately.

Prevention

In most cases, the best prevention involves changing one's habits to avoid bringing on attacks of angina. If blood pressure medication has been prescribed, compliance is a necessity and should be a priority as well. Many healthcare professionals—including physicians, dietitians, and nurses—can provide valuable advice on proper diet, weight control, blood cholesterol levels, and blood pressure. These professionals also offer suggestions about current treatments and information to help stop smoking. In general, the majority of those with angina adjust their lives to minimize episodes of angina, by taking necessary precautions and using medications if recommended and necessary. Coronary artery disease is the underlying problem that should be addressed.

Resources

Organizations

National Heart, Lung and Blood Institute. P.O. Box 30105, Bethesda, MD 20824-0105. (301) 251-1222. http://www.nhlbi.nih.gov.

Other

"Angina." Healthtouch Online Page. Sepember 1997. [cited May 21, 1998]. http://www.healthtouch.com.

angina

[an-ji´nah, an´jĭ-nah] spasmodic, choking, or suffocative pain; now used almost exclusively to denote angina pectoris. adj., adj an´ginal.agranulocytic angina agranulocytosis.crescendo angina old term for unstable angina.angina cru´ris intermittent claudication.herpes angina (angina herpe´tica) herpangina.intestinal angina generalized cramping abdominal pain occurring shortly after a meal and persisting for one to three hours, due to ischemia of the smooth muscle of the bowel.Ludwig's angina see ludwig's angina.angina pec´toris acute pain in the chest resulting from ischemia" >myocardial ischemia (decreased blood supply to the heart muscle); the condition has also been called cardiac pain of effort and emotion because the pain is brought on by physical activity or emotional stress that places an added burden on the heart and increases the need for blood being supplied to the myocardium. Some patients can predict the kinds of events that will precipitate an attack while others are unaware of any relationship between onset of an attack and any particular situation in their lives.
Angina pectoris occurs more frequently in men than in women, and in older persons than in younger persons. It is not a disease entity but a symptom of an underlying disease process involving the arteries that supply blood to the heart muscle. About 90 per cent of all cases can be attributed to coronary atherosclerosis. Studies have shown that at least one of the three major coronary arteries usually is stenosed before angina develops. In most cases, all of the major coronary arteries are involved.
Angina pectoris also can result from stenosis of the aorta, pulmonary stenosis and ventricular hypertrophy, or connective tissue disorders such as systemic lupus erythematosus and periarteritis nodosa that affect the smaller coronary arteries.Symptoms. The chief symptom is chest pain, usually unmistakably distinguished by the patient as different from other types of pain such as that caused by indigestion. It is generally described as a feeling of tightness, strangling, heaviness, or suffocation and is usually concentrated on the left side, beginning just under the sternum; it sometimes radiates to the neck, throat, and lower jaw and down the left arm, and occasionally to the stomach, back, or across to the right side of the chest. The pain seldom lasts more than 15 minutes and is usually relieved by rest and relaxation or by administration of nitrates. If it is not relieved in 10 to 15 minutes, the physician should be notified and the patient taken to a cardiac care unit. The decreased blood supply to the heart makes it especially vulnerable to arrhythmias" >arrhythmias and myocardial infarction, which are the cause of death in about one third of all cases.
Coronary arteriography and ventriculography are valuable in determining the prognosis for angina pectoris. The mortality rate for patients having a narrowing of all three main coronary arteries is higher than for those who have only one vessel involved. Severity of pain is not a good prognostic indicator; some patients with severe discomfort live for many years, while others with mild symptoms die suddenly. An enlarged heart, a third heart sound, ECG abnormalities at rest, and hypertension are all indicative of a poor prognosis.Treatment and Patient Care. Relief from pain by rest and prevention of attacks by avoiding situations which precipitate them are the first steps in the care of the patient with angina. In most cases patients are eager to learn about the disease process causing the pain and want to know how they can participate in control of their attacks. However, compliance with the prescribed regimen usually requires a change in life style and the breaking of some lifelong habits. The known risk factors for coronary heart disease are explained to the patient, and a regimen designed to avoid further damage to the arteries is prescribed.
Organic nitrates may be administered orally or sublingually for relief from anginal pain. They act by dilating the arteries and may be used to treat acute attacks, for long-term prophylaxis and management, or for prophylaxis in situations likely to provoke an attack. Commonly used nitrates are erythrityl tetranitrate, isosorbide dinitrate, and nitroglycerin.
Beta-adrenergic blocking agents, such as propranolol, are used to treat patients who do not respond to weight control and treatment with vasodilators and whose angina significantly limits their activities. These agents decrease the heart rate, blood pressure, and myocardial oxygen consumption and increase the patient's exercise tolerance.
The calcium channel blocking agents (nifedipine, verapamil, diltiazem, and others) are drugs that are particularly beneficial in relieving pain in patients whose angina is the result of coronary artery spasm or constriction. They act by selectively inhibiting the transport of calcium across the cell membrane of myocardial cells and also by reducing myocardial oxygen utilization. Patients most likely to obtain dramatic relief from drugs of this kind are those who experience chest pain while resting or sleeping, upon exposure to cold, or during emotional stress.
Surgical procedures involving arterial bypass and angioplasty have become fairly common as a form of treatment of certain types of ischemic heart disease and resulting angina pectoris. The surgical procedures attempt to bypass the diseased portion of the coronary artery by suturing a vein graft or the internal mammary artery from the aorta to one or more coronary arteries beyond the area of obstruction. In most instances the graft is obtained from the patient's saphenous vein. Angioplasty reestablishes patency of the vessels; in most cases, it is now accompanied by insertion of a stent to help prevent restenosis.
An attitude of calmness and efficiency is most important when caring for a person suffering from an attack of angina pectoris. The pain produces emotional reactions and the strongest of these is fear. Most of these patients know that their pain is resulting from an insufficient supply of oxygen to the heart and they frequently have a feeling of impending death. It usually helps to raise the patient to a sitting position so that breathing is less difficult. The prompt administration of nitroglycerin or the specific drug ordered by the physician should shorten the attack and relieve pain. Above all, the calm presence of someone who knows how to care for them can do much to reassure patients and help them relax, thus lessening the severity of the attack.Plaut's angina necrotizing ulcerative gingivostomatitis.preinfarction angina angina that lasts longer than 15 minutes; it is a symptom of worsening cardiac ischemia.Prinzmetal's angina a variant of angina pectoris in which the attacks occur during rest, exercise capacity is well preserved, and attacks are associated electrocardiographically with elevation of the ST segment. It is cyclic in nature and is believed to be caused by coronary artery spasm.pseudomembranous angina necrotizing ulcerative gingivostomatitis.stable angina chest pain of cardiac origin that has not changed in character, frequency, intensity, or duration for 60 days.unstable angina chest pain of cardiac origin that is variable, usually increasing in frequency and intensity and with irregular timing.variant angina Prinzmetal's angina.Vincent's angina see vincent's angina.

an·gi·na

(an'ji-nă, an-jī'nă), Although the correct classical pronunciation stresses the first syllable (an'gina), the stress is often placed on the second syllable (angi'na) in the U.S. In medical German, the simple word Angina refers not to chest pain due to myocardial ischemia but rather to severe pharyngitis.1. A severe, often constricting pain or sensation of pressure, usually referring to angina pectoris. 2. Older term for a sore throat from any cause. [L. quinsy]

angina

(ăn-jī′nə, ăn′jə-)n.1. Angina pectoris.2. A condition, such as severe sore throat, in which spasmodic attacks of suffocating pain occur.

an·gi′nal adj.an′gi·nose′ (-jə-nōs′) adj.

angina

A sense of suffocation, impending doom and crushing pain in the chest and neck which classically extends to the left arm. Angina is associated with coronary heart disease, and is typically often brought on by exercise.

angina

Angina pectoris Cardiology A condition characterized by 'suffocatingly' intense pain, exertional substernal pressure radiating to the jaw/left shoulder/left arm, associated with N&V, dyspnea, diaphoresis, lasting < 30 min, which is relieved with nitroglycerin and rest, and classically accompanied by a sense of impending doom DiffDx Aortic dissection, costochondritis, GERD, intercostal neuritis, MI, peptic ulcer disease, PTE, tension pneumothorax, unstable angina Diagnosis Clinical history, EKG at rest and during activity, thallium stress test, coronary artery angiography EKG ST segment depression, T wave flattening Risk factor modification Smoking cessation, treat HTN, DM, ↓ cholesterol Management Initial therapy assumes acute MI–ergo aspirin, O₂, beta-blockers, heparin, telemetry monitoring Medical therapy Nitroglycerin, long-acting nitrates, beta-blockers, CCBs Surgical therapy PCTA, CABG, stenting. See Canadian Cardiovascular Society functional classification, Chronic stable angina, High-risk unstable angina, Intestinal angina, Prinzmetal's angina, Recurrent angina, Unstable angina, Variant angina. Cf Prinzmetal's angina.

an·gi·na

(an'ji-nă) A severe, constricting pain; usually refers to angina pectoris. [L. quinsy]

angina

(an-ji'na, an'ji-) [L. angina, quinsy, fr. angere, to choke] 1. Angina pectoris.2. Acute sore throat. anginal (an-ji'nal, an'ji-nal), adjective

abdominal angina

Abdominal pain that occurs after meals, caused by insufficient blood flow to the mesenteric arteries. This symptom typically occurs in patients with extensive atherosclerotic vascular disease and is often associated with significant weight loss. Synonym: intestinal angina; bowel ischemia

Patient care

Medical intervention for abdominal angina can include supportive care including anticoagulant therapy. Surgical intervention includes angioplasty, partial colectomy, (removing the ischemic section of the bowel and reconnecting the remaining ends). It may be necessary to create a colostomy or ileostomy and to correct blockages in the mesenteric arteries. The patient must be monitored for signs and symptoms of peritonitis and/or sepsis. As the patient recovers, patient education focuses on prevention of further episodes, recognition of signs and symptoms including cramping abdominal pain after eating, blood in the stool, red or black stools, diarrhea and/or constipation. It also includes instructions and support for living with permanent or temporary colostomy or ileostomy.

angina decubitus

Attacks of angina pectoris occurring while a person is in a recumbent position.

angina of effort

Angina pectoris with onset during exercise. Synonym: exertional angina

exertional angina

Angina of effort.

intestinal angina

Abdominal angina.

Ludwig angina

See: Ludwig angina

ANGINA PECTORIS

angina pectoris

An oppressive pain or pressure in the chest caused by inadequate blood flow and oxygenation to heart muscle. It is usually due to atherosclerosis of the coronary arteries and in Western cultures is one of the most common emergent complaints bringing adult patients to medical attention. It typically occurs after (or during) events that increase the heart's need for oxygen, e.g., increased physical activity, a large meal, exposure to cold weather, or increased psychological stress. See: illustration; table

Symptoms

Patients typically describe a pain or pressure located behind the sternum and having a tight, burning, squeezing, or binding sensation that may radiate into the neck, jaw, shoulders, or arms and be associated with difficulty in breathing, nausea, vomiting, sweating, anxiety, or fear. The pain is not usually described as sharp or stabbing and is usually not aggravated by deep breathing, coughing, swallowing, or twisting or turning the muscles of the trunk, shoulders, or arms. Women, diabetics, and the elderly may present with atypical symptoms, such as shortness of breath without pain.

Treatment

In health care settings, oxygen, nitroglycerin, and aspirin are provided, and the patient is placed at rest. Morphine sulfate is given for pain that does not resolve after about 15 min of treatment with that regimen. Beta-blocking drugs (such as propranolol or metoprolol) are used to slow the heart rate and decrease blood pressure. They are the mainstay for chronic treatment of coronary insufficiency and are indispensable for treating unstable angina or acute myocardial infarction. At home, patients should rest and use short-acting nitroglycerin. Patients with chronic or recurring angina pectoris may get symptomatic relief from long-acting nitrates or calcium channel blockers. Patients with refractory angina may be treated with combinations of all of these drugs in addition to ranolazine, a sodium channel blocker.

Patient care

The pattern of pain, including OPQRST (onset, provocation, quality, region, radiation, referral, severity, and time), is monitored and documented. Cardiopulmonary status is evaluated for evidence of tachypnea, dyspnea, diaphoresis, pulmonary crackles, bradycardia or tachycardia, altered pulse strength, the appearance of a third or fourth heart sound or mid- to late-systolic murmurs over the apex on auscultation, pallor, hypotension or hypertension, gastrointestinal distress, or nausea and vomiting. The 12-lead electrocardiogram is monitored for ST-segment elevation or depression, T-wave inversion, and cardiac arrhythmias. A health care provider should remain with the patient and provide emotional support throughout the episode. Desired treatment results include reducing myocardial oxygen demand and increasing myocardial oxygen supply. The patient is taught the use of the prescribed form of nitroglycerin for anginal attacks and the importance of seeking medical attention if prescribed dosing does not provide relief. Based on his needs, the patient should be encouraged and assisted to stop smoking, maintain ideal body weight, lower cholesterol by eating a low-fat diet, keep blood glucose under control (if the patient is diabetic), limit salt intake, and exercise (walking, gardening, or swimming regularly for 45 min to an hour every day). The patient is also taught about prescribed beta-adrenergic or calcium channel blockers and any other needed interventions should they become necessary.

Four major forms of angina are identified: 1. stable: predictable frequency and duration of pain that is relieved by nitrates and rest; 2. unstable: pain that is more easily induced and increases in frequency and duration; 3. variant: pain that occurs from unpredictable coronary artery spasm; and 4. microvascular: impairment of vasodilator reserve that causes angina-like chest pain even though the patient’s coronary arteries are normal. Severe and prolonged anginal pain is suggestive of a myocardial infarction.

Class	Description
I	Ordinary physical activity, such as walking or climbing stairs, does not cause angina. Angina occurs with strenuous, rapid, or prolonged exertion at work or recreation.
II	Slight limitation of ordinary activity. Angina occurs on walking or climbing stairs rapidly, walking uphill, walking or stair climbing after meals, in cold, or in wind, under emotional stress, only during the few hours after awakening, or walking more than two level blocks and climbing more than one flight of stairs at a normal pace and in normal conditions.
III	Marked limitation of ordinary physical activity. Angina occurs on walking one to two level blocks and climbing one flight of stairs in normal conditions at a normal pace.
IV	Inability to carry on any physical activity without discomfort—angina symptoms may be present at rest.

preinfarction angina

Angina pectoris occurring in the days or weeks before a myocardial infarction. The symptoms may be unrecognized by patients without a history of coronary artery disease.

silent angina

Unrecognized angina pectoris that presents with symptoms other than chest pain or pressure. The patient may experience dyspnea on exertion, heartburn, nausea, pain in the arm, jaw pain, tenderness in back or arms (in women), or other atypical symptoms. Silent angina pectoris occurs most often in older adults, in women, in postoperative patients who are heavily medicated, or in patients with diabetic neuropathy.

stable angina

Angina that occurs with exercise and is predictable. It is usually promptly relieved by rest or nitroglycerin.

unstable angina

Abbreviation: UA
Angina that has changed to a more frequent and more severe form. Its symptoms include chest pain that occurs with minimal exertion (or that progresses from pain with exertion to pain occurring with minimal exertion or at rest) and may be an indication of a severe obstruction in a coronary artery and impending myocardial infarction. It is a medical emergency, and should be aggressively managed.

variant angina

Angina due to spasm of the coronary arteries rather than from exertion or other increased demands on the heart. The pain typically occurs at rest. During coronary catheterization the spasm is usually found near an atherosclerotic plaque, often in the right coronary artery. Infusions of ergonovine may provoke it. On the electrocardiogram, the diagnostic hallmark is elevation of the ST segments during episodes of resting pain. Treatments include nitrates and calcium channel blocking drugs. Beta-blocking drugs, frequently used as first-line therapy in typical angina pectoris, are often ineffective with this angina. Synonym: Prinzmetal angina

Vincent angina

Necrotizing ulcerative gingivitis.

angina

1. A sore throat severe enough to cause a sensation of choking. 2. ANGINA PECTORIS. 3. One of a number of conditions featuring painful spasms.

an·gi·na

(an'ji-nă) Although the correct classical pronunciation stresses the first syllable (an'gina), the stress is often placed on the second syllable (angi'na) in the U.S.Severe, often constricting pain or sensation of pressure, usually referring to angina pectoris. [L. quinsy]

Patient discussion about angina

Q. I still have chest pain after 5 angioplasties/stents. Does anybody else still have that much angina? A. my uncle had the same problem. went through several catheterization at several different cardiologist (some are well known), but couldn't get this annoying pain off his chest. the weird part was that it didn't even reacted to effort. but eventually (i don't remember the stent amount) one of the cardiologist solved the problem. so don't give up and continue searching the cause!

More discussions about angina

angina

an·gi·na

angina

an•gi•na

angina

angina

Angina

Definition

Description

Angina of effort

Variant angina

Causes and symptoms

Diagnosis

Electrocardiogram (ecg)

Stress test

Angiogram

Treatment

Conservative treatment

Surgical treatment

Key terms

Alternative treatment

Prognosis

Prevention

Resources

Organizations

Other

angina

an·gi·na

angina

angina

angina

an·gi·na

angina

abdominal angina

Patient care

angina decubitus

angina of effort

exertional angina

intestinal angina

Ludwig angina

angina pectoris

Symptoms

Treatment

Patient care

preinfarction angina

silent angina

stable angina

unstable angina

variant angina

Vincent angina

angina

an·gi·na

Patient discussion about angina

angina

Synonyms for angina

noun any disease of the throat or fauces marked by spasmodic attacks of intense suffocative pain

Related Words

noun a heart condition marked by paroxysms of chest pain due to reduced oxygen to the heart

Synonyms

Related Words