Palpitations Glossary of Terms

Ablation: Removal or excision. Ablation is usually carried out surgically. For example, surgical removal of the thyroid gland (a total thyroidectomy) is ablation of the thyroid. The word ablation comes from the Latin ablatum meaning to carry away.
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Abnormal: Not normal. Deviating from the usual structure, position, condition, or behavior. In referring to a growth, abnormal may mean that it is cancerous or premalignant (likely to become cancer ).
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Adrenaline: A substance produced by the medulla (inside) of the adrenal gland, adrenaline (the official name in the British Pharmacopoeia) is synonymous with epinephrine. Technically speaking, adrenaline is a sympathomimetic catecholamine. It causes quickening of the heart beat, strengthens the force of the heart's contraction, opens up the bronchioles in the lungs and has numerous other effects. The secretion of adrenaline by the adrenal is part of the "fight-or-flight" reaction that we have in response to being frightened.

Alcohol: An organic chemical in which one or more hydroxyl (OH) groups are attached to carbon (C) atoms in place of hydrogen (H) atoms. Common alcohols include ethyl alcohol or ethanol (found in alcoholic beverages), methyl alcohol or methanol (can cause blindness) and propyl alcohol or propanol (used as a solvent and antiseptic ). Rubbing alcohol is a mixture of acetone , methyl isobutyl ketone, and ethyl alcohol. In everyday talk, alcohol usually refers to ethanol as, for example, in wine, beer, and liquor. It can cause changes in behavior and be addictive.
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Angina: Chest pain due to an inadequate supply of oxygen to the heart muscle. The chest pain of angina is typically severe and crushing. There is a feeling just behind the breastbone (the sternum) of pressure and suffocation.
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Angiography: A procedure performed to view blood vessels after injecting them with a radioopaque dye that outlines them on x-ray. This technique can be usefully used to look at arteries in many areas of the body, including the brain, neck (carotids), heart, aorta, chest, pulmonary circuit, kidneys, gastrointestinal tract, and limbs.

Angioplasty: Procedure with a balloon-tipped catheter to enlarge a narrowing in a coronary artery. Also called Percutaneous Transluminal Coronary Angioplasty (PTCA).

Aorta: The largest artery in the body, the aorta arises from the left ventricle of the heart, goes up (ascends) a little ways, bends over (arches), then goes down (descends) through the chest and through the abdomen to where ends by dividing into two arteries called the common iliac arteries that go to the legs.
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Aortic: Pertaining to the aorta , the largest artery in the body.
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Aortic stenosis: Narrowing (stenosis) of the heart valve between the left ventricle of the heart and the aorta. This narrowing impedes the delivery of blood through the aorta to the body and makes it tough for the heart to carry out this Herculean task. A normal aortic valve has three leaflets or cusps, but a stenotic valve may have only one cusp (unicuspid) or two cusps (bicuspid), which are thick. stiff and stenotic. Some children with aortic stenosis have chest pain, unusual fatigue, dizziness or fainting. Many children have few or no symptoms. The need for surgery depends on the degree of stenosis. Although surgery may enlarge the stenotic valve the valve remains deformed and eventually may need to be replaced with an artificial one. A procedure called balloon valvuloplasty has been used in some children with aortic stenosis. Persons with aortic stenosis need medical follow-up all their lives since even mild stenosis may worsen over time and need treatment.

Arrhythmia: An abnormal heart rhythm.
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Artery: A vessel that carries blood high in oxygen content away from the heart to the farthest reaches of the body. Since blood in arteries is usually full of oxygen, the hemoglobin in the red blood cells is oxygenated. The resultant form of hemoglobin (oxyhemoglobin) is what makes arterial blood look bright red.
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Asthma : A common disorder in which chronic inflammation of the bronchial tubes (bronchi) makes them swell, narrowing the airways. Asthma involves only the bronchial tubes and does not affect the air sacs ( alveoli ) or the lung tissue (the parenchyma of the lung) itself.
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Atenolol : A medication that blocks the action of a portion of the involuntary nervous system that stimulates the pace of the heartbeat. By blocking the action of these nerves, atenolol reduces the heart rate and is useful in treating abnormally rapid heart rhythms. Atenolol also reduces the force of heart muscle contraction, lowers blood pressure, and is helpful in treating angina . It is also used for the prevention of migraine headaches and the treatment of certain types of tremors. The brand name is Tenormin. Generic is available.
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Atria: The plural of atrium. The atria are the two smaller chambers of the heart. Each atrium consists of an open space with recessed walls.
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Atrial: Pertaining to the atria, the upper chambers of the heart, as in atrial fibrillation and atrial septal defect.

Atrial fibrillation: Abnormal irregular heart rhythm with chaotic generation of electrical signals in the atria of the heart. Familiarly called atrial fib.

Atrial flutter: Well-organized but overly rapid contractions of the atrium of the heart (usually at a rate of 250-350 contractions per minute).
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Atrium: One of the two smaller chambers of the heart. Each atrium consists of an open space with recessed walls. The plural of atrium is atria.
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AV node: An electrical relay station between the atria (the upper) and the ventricles (the lower chambers of the heart). Electrical signals from the atria must pass through the AV node to reach the ventricles.
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Blood: The familiar red fluid in the body that contains white and red blood cells, platelets, proteins, and other elements. The blood is transported throughout the body by the circulatory system. Blood functions in two directions: arterial and venous. Arterial blood is the means by which oxygen and nutrients are transported to tissues while venous blood is the means by which carbon dioxide and metabolic by-products are transported to the lungs and kidneys, respectively, for removal from the body.

Blood pressure: The blood pressure is the pressure of the blood within the arteries. It is produced primarily by the contraction of the heart muscle. It's measurement is recorded by two numbers. The first (systolic pressure) is measured after the heart contracts and is highest. The second (diastolic pressure) is measured before the heart contracts and lowest. A blood pressure cuff is used to measure the pressure. Elevation of blood pressure is called "hypertension".

Bradycardia: A slow heart rate, usually defined as less than 60 beats per minute.
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Brain: That part of the central nervous system that is located within the cranium ( skull ). The brain functions as the primary receiver, organizer and distributor of information for the body. It has two (right and left) halves called "hemispheres."
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Bypass: An operation in which a surgeon creates a new tubular pathway for the movement of fluids and/or other substances in the body.
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Caffeine: A stimulant found naturally in coffee beans, tea leaves, cocoa beans (chocolate) and kola nuts (cola) and added to soft drinks, foods, and medicines. A cup of coffee has 100-250 milligrams of caffeine. Black tea brewed for 4 minutes has 40-100 milligrams. Green tea has one-third as much caffeine as black tea.
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Calcium: A mineral found mainly in the hard part of bones, where it is stored. Calcium is added to bones by cells called osteoblasts and is removed from bones by cells called osteoclasts. Calcium is essential for healthy bones. It is also important for muscle contraction, heart action, nervous system maintenance, and normal blood clotting. Food sources of calcium include dairy foods, some leafy green vegetables such as broccoli and collards, canned salmon, clams, oysters, calcium-fortified foods, and tofu. According to the National Academy of Sciences, adequate intake of calcium is 1,200 milligrams a day (four glasses of milk) for men and women 51 and older, 1,000 milligrams a day for adults 19 through 50, and 1,300 milligrams a day for children 9 through 18. The upper limit for calcium intake is 2.5 grams daily.

Cardiac: Having to do with the heart.
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Cardiomyopathy: Disease of the heart muscle (the myocardium). From the Greek roots: "cardio-", heart + "mys", muscle + "pathos", disease = disease (of the) heart muscle.

Cassette: A pre-existing structure into which an insert can be moved. In molecular biology, a gene conversion process in which the old gene is replaced with a copy of a silent gene and the new copy becomes active. As the process involves replacing one ready made construct with another in an active slot, it is termed a cassette mechanism.

Catheter: A thin, flexible tube . For example, a catheter placed in a vein provides a pathway for giving drugs, nutrients, fluids, or blood products. Samples of blood can also be withdrawn through the catheter.
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Chest: The area of the body located between the neck and the abdomen . The chest contains the lungs , the heart and part of the aorta . The walls of the chest are supported by the dorsal vertebrae , the ribs , and the sternum .
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Chest pain: There are many causes of chest pain. One is angina which results from inadequate oxygen supply to the heart muscle. Angina can be caused by coronary artery disease or spasm of the coronary arteries. Chest pain can also be due to a heart attack (coronary occlusion) and other important diseases such as, for example, dissection of the aorta and a pulmonary embolism. Do not try to ignore chest pain and "work (or play) though it." Chest pain is a warning to seek medical attention.

Cocaine: The most potent stimulant of natural origin, a bitter addictive anesthetic (pain blocker) which is extracted from the leaves of the coca scrub (Erythroxylon coca) indigenous to the Andean highlands of South America.
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Condition: The term "condition" has a number of biomedical meanings including the following:

1. An unhealthy state, such as in "this is a progressive condition."
2. A state of fitness, such as "getting into condition."
3. Something that is essential to the occurrence of something else; essentially a "precondition."
4. As a verb: to cause a change in something so that a response that was previously associated with a certain stimulus becomes associated with another stimulus; to condition a person, as in behavioral conditioning.

Contraction: The tightening and shortening of a muscle.

Contrast: Short for "contrast media." Contrast media are X-ray dyes used to provide contrast, for example, between blood vessels and other tissue.

Coronary arteries: The vessels that supply the heart muscle with blood rich in oxygen. They are called the coronary arteries because they encircle the heart in the manner of a crown. The word "coronary" comes from the Latin "corona" and Greek "koron" meaning crown. Like other arteries, the coronaries may be subject to arteriosclerosis (hardening of the arteries). There are a number of coronary arteries. Those most often bypassed today include the right coronary artery, the posterior descending coronary artery, the left main coronary artery, the left anterior descending coronary artery and the left circumflex coronary artery. Plaques obstructing the coronary arteries may also be treated by balloon angioplasty , stents, and other techniques.
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Depression : An illness that involves the body, mood, and thoughts, that affects the way a person eats and sleeps, the way one feels about oneself, and the way one thinks about things. A depressive disorder is not the same as a passing blue mood. It is not a sign of personal weakness or a condition that can be wished away. People with a depressive disease cannot merely "pull themselves together" and get better. Without treatment, symptoms can last for weeks, months, or years. Appropriate treatment, however, can help most people with depression.
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Disease: Illness or sickness often characterized by typical patient problems (symptoms) and physical findings (signs). Disruption sequence: The events that occur when a fetus that is developing normally is subjected to a destructive agent such as the rubella (German measles) virus.

Dizziness : Painless head discomfort with many possible causes including disturbances of vision, the brain, balance (vestibular) system of the inner ear, and gastrointestinal system. Dizziness is a medically indistinct term which laypersons use to describe a variety of conditions ranging from lightheadedness, unsteadiness to vertigo.
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Echocardiography: Echocardiography is a diagnostic test which uses ultrasound waves to make images of the heart chambers, valves and surrounding structures. It can measure cardiac output and is a sensitive test for inflammation around the heart (pericarditis). It can also be used to detect abnormal anatomy or infections of the heart valves.

Electrocardiogram : A recording of the electrical activity of the heart. An electrocardiogram is a simple, non-invasive procedure. Electrodes are placed on the skin of the chest and connected in a specific order to a machine that, when turned on, measures electrical activity all overaround the heart. Output is usually in the form of a long scroll of paper displaying a printed graph of activity. Newer models output the data directly to a computer and screen, although a print-out may still be made.
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Electrolyte: An electrolyte is a substance that will dissociate into ions in solution and acquire the capacity to conduct electricity. The electrolytes include sodium, potassium, chloride, calcium and phosphate. Informally, called lytes. (The clue to the word electrolyte is in the lyte which comes from the Greek lytos meaning that may be dissolved.)
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Embolism: The obstruction of a blood vessel by a foreign substance or a blood clot blocking the vessel. Something travels through the bloodstream, lodges in a vessel and plugs it.
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Emphysema: 1) A lung condition featuring an abnormal accumulation of air in the lung's many tiny air sacs, a tissue called alveoli. As air continues to collect in these sacs, they become enlarged, and may break, or be damaged and form scar tissue. Emphysema is strongly associated with smoking cigarettes, a practice that causes lung irritation. It can also be associated with or worsened by repeated infection of the lungs, such as is seen in chronic bronchitis. The best response to the early warning signs of emphysema is prevention: stop smoking and get immediate treatment for incipient lung infections. Curing established emphysema is not yet possible. Because patients don't have an adequate amount of space in the lungs to breathe, they gasp for breath, and may not be able to obtain enough oxygen. Those with severe emphysema usually end up using an oxygen machine to breathe. In some cases, medication may be helpful to ease symptoms or to treat infection in already-damaged lungs.
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Event: A set of outcomes. Cardiovascular events might include a heart attack and gastrointestinal events a GI bleed. The use of the term "event" in medicine comes from probability theory.

Exercise test: A test (sometimes called the treadmill test or exercise treadmill test) in which a continuous electrocardiogram ( ECG or EKG) recording of the heart is made as the patient performs increasing levels of exercise on the treadmill which is tilted to produce the effect of going up a small hill. The patient can stop the test at any time, if necessary. Afterwards the patient has heart and blood pressure checked.
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Exercise treadmill: Exercise on a treadmill, a machine with a moving strip on which one walks without moving forward. A treadmill was originally a wide wheel turned by the weight of people climbing on steps around its edge, used in the past to provide power for machines or as a punishment in prisons.
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Fatigue: A condition characterized by a lessened capacity for work and reduced efficiency of accomplishment, usually accompanied by a feeling of weariness and tiredness. Fatigue can be acute and come on suddenly or chronic and persist.
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Fever : Although a fever technically is any body temperature above the normal of 98.6 degrees F. (37 degrees C.), in practice a person is usually not considered to have a significant fever until the temperature is above 100.4 degrees F (38 degrees C.).
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Fibrillation: In matters of the heart (cardiology), fibrillation is incoordinate twitching of the heart muscle fibers.
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Flutter: Flutter is a rapid vibration or pulsation. The difference between flutter and fibrillation is that flutter is well organized while fibrillation is not.
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Graft: Healthy skin, bone, or other tissue taken from one part of the body to replace diseased or injured tissue removed from another part of the body.
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Groin: In anatomy, the area where the upper thigh meets the trunk. More precisely, the fold or depression marking the juncture of the lower abdomen and the inner part of the thigh.
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Health: As officially defined by the World Health Organization, a state of complete physical, mental, and social well-being, not merely the absence of disease or infirmity.

Heart: The muscle that pumps blood received from veins into arteries throughout the body. It is positioned in the chest behind the sternum (breastbone; in front of the trachea, esophagus, and aorta; and above the diaphragm muscle that separates the chest and abdominal cavities. The normal heart is about the size of a closed fist, and weighs about 10.5 ounces. It is cone-shaped, with the point of the cone pointing down to the left. Two-thirds of the heart lies in the left side of the chest with the balance in the right chest.
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Heart attack: The death of heart muscle due to the loss of blood supply. The loss of blood supply is usually caused by a complete blockage of a coronary artery, one of the arteries that supplies blood to the heart muscle. Death of the heart muscle, in turn, causes chest pain and electrical instability of the heart muscle tissue.
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Heart disease: Any disorder that affects the heart. Sometimes the term "heart disease" is used narrowly and incorrectly as a synonym for coronary artery disease. Heart disease is synonymous with cardiac disease but not with cardiovascular disease which is any disease of the heart or blood vessels. Among the many types of heart disease, see, for example: Angina; Arrhythmia; Congenital heart disease; Coronary artery disease (CAD); Dilated cardiomyopathy; Heart attack (myocardial infarction); Heart failure; Hypertrophic cardiomyopathy; Mitral regurgitation; Mitral valve prolapse; and Pulmonary stenosis.

Heart failure : Inability of the heart to keep up with the demands on it and, specifically, failure of the heart to pump blood with normal efficiency. When this occurs, the heart is unable to provide adequate blood flow to other organs such as the brain, liver and kidneys. Heart failure may be due to failure of the right or left or both ventricles. The signs and symptoms depend upon which side of the heart is failing. They can include shortness of breath (dyspnea), asthma due to the heart (cardiac asthma), pooling of blood (stasis) in the general body (systemic) circulation or in the liver's (portal) circulation, swelling ( edema ), blueness or duskiness (cyanosis), and enlargement (hypertrophy) of the heart.
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Heart muscle: A type of muscle with unique features only found in the heart. The heart muscle, or cardiac muscle, is medically called the myocardium ("myo-" being the prefix denoting muscle).

Heart rate: The number of heart beats per unit time, usually per minute. The heart rate is based on the number of contractions of the ventricles (the lower chambers of the heart). The heart rate may be too fast ( tachycardia ) or too slow ( bradycardia ). The pulse is bulge of an artery from the wave of blood coursing through the blood vessel as a result of the heart beat. The pulse is often taken at the wrist to estimate the heart rate.
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Heart valves: There are four heart valves. All are one-way valves. Blood entering the heart first passes through the tricuspid valve and then the pulmonary valve. After returning from the lungs, the blood passes through the mitral (bicuspid) valve and exits via the aortic valve.

High blood pressure : Also known as hypertension, high blood pressure is, by definition, a repeatedly elevated blood pressure exceeding 140 over 90 mmHg -- a systolic pressure above 140 with a diastolic pressure above 90.
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Holter monitor: A type of portable heart monitor. The Holter monitor is a small portable electrocardiogram ( ECG ). The device is worn in a pouch around the neck or waist. It keeps a record of the heart rhythm, typically over a 24-hour period, while the patient keeps a diary recording their activities and any symptoms they may feel. The ECG recording is then correlated with the person's record of their activities and symptoms. The Holter monitor is useful for identifying disturbances which are sporadic and which are not readily identified with the usual resting electrocardiogram test.
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Hormone: A chemical substance produced in the body that controls and regulates the activity of certain cells or organs.
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Hypoxia: A subnormal concentration of oxygen. By contrast with normoxia (normal oxygen) and anoxia (the absence or near absence of oxygen). From hyp– (below) + -ox- (oxygen) + –ia.

Implantation: The act of setting in firmly.
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Impotence : A common problem among men characterized by the consistent inability to sustain an erection sufficient for sexual intercourse or the inability to achieve ejaculation , or both. Impotence can vary. It can involve a total inability to achieve an erection or ejaculation, an inconsistent ability to do so, or a tendency to sustain only very brief erections.
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Inflammation: A basic way in which the body reacts to infection , irritation or other injury, the key feature being redness, warmth, swelling and pain . Inflammation is now recognized as a type of nonspecific immune response .
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Iodine: An essential element in the diet used by the thyroid gland to make thyroid hormones .
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Ischemia: Inadequate blood supply (circulation) to a local area due to blockage of the blood vessels to the area.

Left atrium: The upper right chamber of the heart. The left atrium receives oxygenated blood from the lungs and pumps it down into the left ventricle which delivers it to the body.

Left ventricle: The left lower chamber of the heart that receives blood from the left atrium and pumps it out under high pressure through the aorta to the body.

Low blood pressure : Any blood pressure that is below the normal expected for an individual in a given environment. Low blood pressure is also referred to as hypotension.
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Magnesium: A mineral involved in many processes in the body including nerve signaling, the building of healthy bones, and normal muscle contraction . About 350 enzymes are known to depend on magnesium.
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Mapping: Charting the location of genes on chromosomes.

Medication: 1. A drug or medicine. 2. The administration of a drug or medicine. (Note that "medication" does not have the dangerous double meaning of "drug.")

Mitral valve: A valve in the heart situated between the left atrium and the left ventricle that permits blood to flow from the left atrium into the left ventricle but not in the reverse direction.
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Mitral valve prolapse : Drooping down or abnormal bulging of the mitral valve's cusps backward into the atrium during the contraction of the heart. Mitral valve prolapse is often an asymptomatic condition but it may be marked by mitral regurgitation with symptoms (as chest pain, fatigue, dizziness, dyspnea, or palpitations) with a tendency in some cases to endocarditis or ventricular tachycardia.
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Muscle: Muscle is the tissue of the body which primarily functions as a source of power. There are three types of muscle in the body. Muscle which is responsible for moving extremities and external areas of the body is called "skeletal muscle." Heart muscle is called "cardiac muscle." Muscle that is in the walls of arteries and bowel is called "smooth muscle."

Node: Literally a knot, a node is a collection of tissue. For example a lymph node, is a collection of lymphoid tissue. A nodule is a small node, a little collection of tissue.
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Onset: In medicine, the first appearance of the signs or symptoms of an illness as, for example, the onset of rheumatoid arthritis . There is always an onset to a disease but never to the return to good health. The default setting is good health.
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Oxygen: A colorless, odorless and tasteless gas that makes up about 20% of the air we breathe (and at least half the weight of the entire solid crust of the earth) and which combines with most of the other elements to form oxides. Oxygen is essential to human, animal and plant life.
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Pacemaker: A system that sends electrical impulses to the heart in order to set the heart rhythm. The pacemaker can be the normal "natural" pacemaker of the heart or it can be an electronic device.
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Pain: An unpleasant sensation that can range from mild, localized discomfort to agony. Pain has both physical and emotional components. The physical part of pain results from nerve stimulation. Pain may be contained to a discrete area, as in an injury, or it can be more diffuse, as in disorders like fibromyalgia . Pain is mediated by specific nerve fibers that carry the pain impulses to the brain where their conscious appreciation may be modified by many factors.
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Palpitations: Unpleasant sensations of irregular and/or forceful beating of the heart. In some patients with palpitations, no heart disease or abnormal heart rhythms can be found. In others, palpitations result from abnormal heart rhythms (arrhythmias). Arrhythmias refer to heartbeats that are too slow, too rapid, irregular, or too early.

Paroxysmal atrial tachycardia: Abbreviated PAT. Bouts of rapid, regular heart beating that originate in the upper chamber (atrium) of the heart due to abnormalities in the atrioventricular (AV) node that lead to rapid firing of electrical impulses from the atrium that bypass the AV node. PAT tends to occur under certain conditions, including excess alcohol consumption, stress, caffeine use, overactive thyroid or excessive thyroid hormone intake, and use of certain drugs. PAT is an example of an arrhythmia in which the abnormality is in the electrical system of the heart, while the heart muscle and valves may be normal.

PAT: Paroxysmal atrial tachycardia .

Pericarditis: Inflammation of the lining around the heart (the pericardium) causing chest pain and accumulation of fluid around the heart (pericardial effusion).

Potassium: The major positive ion (cation) found inside of cells. The chemical notation for potassium is K⁺.
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Premature contraction: See: Extrasystole.

Pulmonary: Having to do with the lungs. (The word comes from the Latin pulmo for lung).

Pulmonary embolism: The obstruction of the pulmonary artery or a branch of it leading to the lungs by a blood clot, usually from the leg, or foreign material causing sudden closure of the vessel. (Embolus is from the Greek "embolos" meaning plug.)
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Pulmonary vein: One of four vessels that carry aerated blood from the lungs to the left atrium of the heart. (The four are the right and left superior and inferior pulmonary veins). The pulmonary veins are the only veins that carry bright red oxygenated blood.

Pulse: The rhythmic contraction and expansion of an artery due to the surge of blood from the beat of the heart. The pulse is most often measured by feeling the arteries of the wrist. There is also a pulse, although far weaker, in veins.

Recurrence: The return of a sign, symptom or disease after a remission. The reappearance of cancer cells at the same site or in another location is, unfortunately, a familiar form of recurrence.
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Rest: 1. Repose. Relaxation.
2. A fragment of embryonic tissue that has been retained after the period of embryonic development. Also called an embryonic rest.

Right atrium: The right upper chamber of the heart. The right atrium receives deoxygenated blood from the body through the vena cava and pumps it into the right ventricle which then sends it to the lungs to be oxygenated.

Right ventricle: The lower right chamber of the heart that receives deoxygenated blood from the right atrium and pumps it under low pressure into the lungs via the pulmonary artery.
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SA node: The SA node (SA stands for sinoatrial) is one of the major elements in the cardiac conduction system, the system that controls the heart rate. This stunningly designed system generates electrical impulses and conducts them throughout the muscle of the heart, stimulating the heart to contract and pump blood.
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Section: 1) In anatomy, a slice of tissue. A biopsy obtained by surgery is usually sectioned (sliced), and these sections are inspected under a microscope. 2) In obstetrics, short for Caesarian section. 3) In surgery, the division of tissue during an operation.

Sense: In biology and medicine, the faculty of sensory reception. The ability to convey specific types of external or internal stimuli to the brain and perceive them. Sensory reception occurs through a process known as transduction in which stimuli are converted into nerve impulses which are relayed to the brain.
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Shock: In medicine, shock is a critical condition brought on by a sudden drop in blood flow through the body. There is failure of the circulatory system to maintain adequate blood flow. This sharply curtails the delivery of oxygen and nutrients to vital organs. It also compromises the kidney and so curtails the removal of wastes from the body. Shock can be due to a number of different mechanisms including not enough blood volume (hypovolemic shock) and not enough output of blood by the heart (cardiogenic shock). The signs and symptoms of shock include low blood pressure (hypotension), overbreathing (hyperventilation), a weak rapid pulse, cold clammy grayish-bluish (cyanotic) skin, decreased urine flow (oliguria), and mental changes (a sense of great anxiety and foreboding, confusion and, sometimes, combativeness).
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Side effects: Problems that occur when treatment goes beyond the desired effect. Or problems that occur in addition to the desired therapeutic effect.
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Sinus: 1. An air-filled cavity in a dense portion of a skull bone. The sinuses decrease the weight of the skull. The sinuses are formed in four right-left pairs. The frontal sinuses are positioned behind the forehead, while the maxillary sinuses are behind the cheeks. The sphenoid and ethmoid sinuses are deeper in the skull behind the eyes and maxillary sinuses. The sinuses are lined by mucous-secreting cells. Air enters the sinuses through small opening in bone called ostia. If an ostium is blocked, air cannot pass into the sinus and likewise mucous cannot drain out. See also: Sinusitis .
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Sinus tachycardia: A fast heartbeat (tachycardia) because of rapid firing of the sinoatrial (sinus) node.
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Sodium: The major positive ion (cation) in fluid outside of cells. The chemical notation for sodium is Na⁺. When combined with chloride, the resulting substance is table salt.
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Stenosis: A narrowing, as in:

• aortic stenosis (narrowing of the aortic valve of the heart),
• pulmonary stenosis (narrowing of the pulmonary valve of the heart),
• pyloric stenosis (narrowing of the outlet of the stomach), and
• spinal stenosis (narrowing of the vertebral canal).

Stress: Forces from the outside world impinging on the individual. Stress is a normal part of life that can help us learn and grow. Conversely, stress can cause us significant problems.
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Surgery: The word "surgery" has multiple meanings. It is the branch of medicine concerned with diseases and conditions which require or are amenable to operative procedures. Surgery is the work done by a surgeon. By analogy, the work of an editor wielding his pen as a scalpel is s form of surgery. A surgery in England (and some other countries) is a physician's or dentist's office.
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Symptom: Any subjective evidence of disease. Anxiety, lower back pain, and fatigue are all symptoms. They are sensations only the patient can perceive. In contrast, a sign is objective evidence of disease. A bloody nose is a sign. It is evident to the patient, doctor, nurse and other observers.

Syncope: Partial or complete loss of consciousness with interruption of awareness of oneself and ones surroundings. When the loss of consciousness is temporary and there is spontaneous recovery, it is referred to as syncope or, in nonmedical quarters, fainting . Syncope accounts for one in every 30 visits to an emergency room. It is pronounced sin-ko-pea.
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Tachycardia: A rapid heart rate, usually defined as greater than 100 beats per minute. The tachycardias include sinus tachycardia, paroxysmal atrial tachycardia (PAT), and ventricular tachycardia.
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Tenormin: See: Atenolol.

Thyroid: 1. The thyroid gland. Also, pertaining to the thyroid gland. 2. A preparation of the thyroid gland used to treat hypothyroidism. 3. Shaped like a shield. (The thyroid gland was so-named by Thomas Wharton in 1656 because it was shaped like an ancient Greek shield.)

Thyroid hormone: A chemical substance made by the thyroid gland for export into the bloodstream. The thyroid gland needs iodine to make thyroid hormones. The two most important thyroid hormones are thyroxine (T4) and triiodothyronine (T3).
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Tissue: A tissue in medicine is not like a piece of tissue paper. It is a broad term that is applied to any group of cells that perform specific functions. A tissue in medicine need not form a layer. Thus,

• The bone marrow is a tissue;
• Connective tissue consists of cells that make up fibers in the framework supporting other body tissues; and
• Lymphoid tissue is the part of the body's immune system that helps protect it from bacteria and other foreign entities.

Toxicity: The degree to which a substance can harm humans or animals.
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Treadmill: A machine with a moving strip on which one walks without moving forward. A treadmill was originally a wide wheel turned by the weight of people climbing on steps around its edge, used in the past to provide power for machines or as a punishment in prisons.
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Ultrasound : High-frequency sound waves. Ultrasound waves can be bounced off of tissues using special devices. The echoes are then converted into a picture called a sonogram. Ultrasound imaging, referred to as ultrasonography, allows physicians and patients to get an inside view of soft tissues and body cavities, without using invasive techniques. Ultrasound is often used to examine a fetus during pregnancy. There is no convincing evidence for any danger from ultrasound during pregnancy.
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Vein: A blood vessel that carries blood low in oxygen content from the body back to the heart. The deoxygenated form of hemoglobin (deoxyhemoglobin) in venous blood makes it appear dark. Veins are part of the afferent wing of the circulatory system which returns blood to the heart.
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Ventricle: A chamber of an organ. For example, the four connected cavities (hollow spaces) in the central portion of the brain and the lower two chambers of the heart are called ventricles.

Ventricles: 1, The right ventricle and the left ventricle, the lower two chambers of the heart. 2. Two or more of the four connected spaces within the central portion of the brain.

Ventricular: Pertaining to the ventricles, the lower chambers of the heart, as in ventricular fibrillation and ventricular septal defect.

Ventricular arrhythmias: Abnormal rapid heart rhythms (arrhythmias) that originate in the lower chambers of the heart (the ventricles). Ventricular arrhythmias include ventricular tachycardia and ventricular fibrillation. Both are life threatening arrhythmias most commonly associated with heart attacks or scarring of the heart muscle from previous heart attack.

Ventricular fibrillation: An abnormal irregular heart rhythm whereby there are very rapid uncoordinated fluttering contractions of the lower chambers (ventricles) of the heart. Ventricular fibrillation disrupts the synchrony between the heartbeat and the pulse beat. Ventricular fibrillation is most commonly associated with heart attacks or scarring of the heart muscle from previous heart attack. It is life threatening. Ventricular fibrillation is most commonly associated with heart attacks or scarring of the heart muscle from previous heart attack. It is life threatening.

Ventricular tachycardia: An abnormally rapid heart rhythm that originates from a ventricle , one of the lower chambers of the heart. Although the beat is regular, ventricular tachycardia is life-threatening because it can lead to a dreaded condition, ventricular fibrillation .
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X-ray: 1. High-energy radiation with waves shorter than those of visible light. X-rays possess the properties of penetrating most substances (to varying extents), of acting on a photographic film or plate (permitting radiography), and of causing a fluorescent screen to give off light (permitting fluoroscopy). In low doses X-rays are used for making images that help to diagnose disease, and in high doses to treat cancer . Formerly called a Roentgen ray. 2. An image obtained by means of X-rays.
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From the Doctors at MedicineNet.com

Electrocardiogram (ECG or EKG) - Read about the Electrocardiogram (ECG, EKG) procedure to test the electrical activity of the heart. Source:MedicineNet Chest X-ray - A chest x-ray is a radiology test that involves exposing the chest briefly to radiation to produce an image of the chest and the internal organs of the chest. chest x-ray can be used to define abnormalities of the lungs such as excessive fluid, pneumonia, bronchitis, asthma, cysts, and cancers. Source:MedicineNet Panic Attacks - Read about panic attack (panic disorder) symptoms, causes (stress, anxiety, fear) and treatment (medication, psychotherapy). Learn how to prevent panic attacks. Source:MedicineNet Read 88 more Palpitations related articles ... Amitiza Treats Irritable Bowel With Constipation Migraine Medications May Cause 'Serotonin Syndrome' Combination of Thyroid Medicines Not Necessary ADHD Drugs: Heart Screen Recommended New Atrial Fibrillation Surgery Improves Results 15 Million Americans Suffer From Social Anxiety Disorder Talk Therapy Curbs Panic Disorder