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February 10, 2012

Electrocardiogram (ECG or EKG) Glossary of Terms

The following are health and medical definitions of terms that appear in the Electrocardiogram (ECG or EKG) article.

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).

Acute: Of abrupt onset, in reference to a disease. Acute often also connotes an illness that is of short duration, rapidly progressive, and in need of urgent care.
See the entire definition of Acute

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.
See the entire definition of Angina

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.
See the entire definition of Artery

Blood clots: Blood that has been converted from a liquid to a solid state. Also called a thrombus.
See the entire definition of Blood clots

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".

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.

Learn more about calcium with evidence-based information on RxList.

Cardiac: Having to do with the heart.

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.
See the entire definition of Chest

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.

Congenital: Present at birth. A condition that is congenital is one that is present at birth. There are numerous uses of "congenital" in medicine. There are, for example, congenital abnormalities. (For more examples, see below.)
See the entire definition of Congenital

Coronary artery disease: A major cause of illness and death, coronary artery disease (CAD) begins when hard cholesterol substances (plaques) are deposited within a coronary artery.
See the entire definition of Coronary artery disease

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.
See the entire definition of Dizziness

ECG: Abbreviation for electrocardiogram or EKG. The K is from "kardio" (in German).

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.
See the entire definition of Electrocardiogram back to top

Embolus: Something that travels through the bloodstream, lodges in a blood vessel and blocks it. Examples of emboli are a detached blood clot, a clump of bacteria, and foreign material such as air.
See the entire definition of Embolus

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.
See the entire definition of Emphysema

Extremity: The extremities in medical language are not freezing cold or scorching heat but rather the uttermost parts of the body. The extremities are simply the hands and feet.
See the entire definition of Extremity

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.
See the entire definition of Heart

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.
See the entire definition of Heart attack

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 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).

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.
See the entire definition of High blood pressure

Hypertrophy: Enlargement or overgrowth of an organ or part of the body due to the increased size of the constituent cells. Hypertrophy occurs in the biceps and heart because of increased work. Cardiac hypertrophy is recognizable microscopically by the increased size of the cells. The term hypertrophy is applied to the enlargement of the uterus during pregnancy. The term benign prostatic hypertrophy is a misnomer because the increased size of the prostate is due to hyperplasia, an increase in the number of cells.

Infarction: The formation of an infarct, an area of tissue death due to a local lack of oxygen.
See the entire definition of Infarction

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.
See the entire definition of Inflammation

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.
See the entire definition of Magnesium

Metabolic: Relating to metabolism, the whole range of biochemical processes that occur within us (or any living organism). Metabolism consists of anabolism (the buildup of substances) and catabolism (the breakdown of substances).
See the entire definition of Metabolic

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."

Myocardial infarction: A heart attack. Abbreviated MI.
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Myocarditis: Inflammation of the myocardium, the heart muscle.
See the entire definition of Myocarditis

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.
See the entire definition of Pain

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.

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+.
See the entire definition of Potassium

Predispose: To make more likely or render susceptible. Smoking predisposes to a number of diseases, including esophageal cancer.

Preoperative: Before surgery. As opposed to postoperative, after surgery.

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

Pulmonary embolus: A blood clot that has passed into and occluded the lung's pulmonary artery. An embolus causes an embolism. In this case, the embolus, a clot or foreign material, has been carried through the blood into the pulmonary artery or one of its branches, plugging the vessel.

Shortness of breath: Difficulty in breathing. Medically referred to as dyspnea. Shortness of breath can be caused by respiratory (breathing passages and lungs) or circulatory (heart and blood vessels) conditions. See also dyspnea.

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.
See the entire definition of Stress

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.
See the entire definition of Surgery

Systemic: Affecting the entire body. A systemic disease such as diabetes can affect the whole body. Systemic chemotherapy employs drugs that travel through the bloodstream and reach and affect cells all over the body.

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.)
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Suggested Reading on Electrocardiogram (ECG or EKG) by Our Doctors

  • Related Diseases & Conditions

    • Low Blood Pressure
      • Low blood pressure, also referred to as hypotension, is blood pressure that is so low that it causes symptoms or signs due to the low flow of blood through the arteries and veins. Some of the symptoms of low blood pressure include light-headedness, dizziness, or even fainting if not enough blood is getting to the brain. Diseases and medications can also cause low blood pressure. When the flow of blood is too low to deliver enough oxygen and nutrients to vital organs such as the brain, heart, and kidneys; the organs do not function normally and may be permanently damaged.
    • Congestive Heart Failure
      • Congestive heart failure (CHF) is a condition in which the heart's function as a pump is inadequate to meet the body's needs. A poor blood supply resulting from congestive heart failure may cause the body's organ systems to fail, leading to a weakened heart muscle and fluid accumulation in the lungs and body tissue. There are many diseases that can impair pumping efficiency and symptoms of congestive heart failure including fatigue, diminished exercise capacity, shortness of breath, and swelling. Treatments include lifestyle modifications, medications, heart transplant, and therapy.
    • Dizziness
      • Dizziness is a symptom that is often applies to a variety of sensations including lightheadedness and vertigo. Causes of dizziness include low blood pressure, heart problems, anemia, dehydration, and more. Treatment of dizziness depends on the cause.
    • Blood Clots
      • Blood clots can occur in the venous and arterial vascular system. Blood clots can form in the heart, legs, arteries, veins, bladder, urinary tract and uterus. Risk factors for blood clots include high blood pressure and cholesterol, diabetes, smoking, and family history. Symptoms of a blood clot depend on the location of the clot. Some blood clots are a medical emergency. Blood clots are treated depending upon the cause of the clot. Blood clots can be prevented by lowering the risk factors for developing blood clots.
    • Stroke
      • A stroke results from impaired oxygen delivery to brain cells via the bloodstream. A stroke is also referred to as a CVA, or cerebrovascular incident. Symptoms of stroke include: sudden numbness or weakness of the face, arm or leg. Sudden confusion, trouble speaking or understanding. Sudden trouble seeing in one or both eyes, sudden trouble walking, dizziness, or loss of balance, and/or sudden severe headache with no known cause. A TIA, or transient ischemic attack is a short-lived temporary impairment of the brain caused by loss of blood supply. Stroke is a medical emergency.
    • Pulmonary Embolism (Blood Clot in the Lung)
      • A pulmonary embolism occurs when a piece of a blood clot from deep vein thrombosis (DVT) breaks off and travels to an artery in the lung where it blocks the artery and damages the lung. The most common symptoms of a pulmonary embolism are shortness of breath, chest pain, and a rapid heart rate.
    • Angina
      • Angina is chest pain that is due to an inadequate supply of oxygen to the heart muscle. Angina can be caused by coronary artery disease or spasm of the coronary arteries. EKG, exercise treadmill, stress echocardiography, stress thallium, and cardiac catheterization are important tests used in the diagnosis of angina.
    • Palpitations
      • Palpitations are unpleasant sensations of irregular and/or forceful beating of the heart. Palpitations can be relieved in many patients by stress reduction, stopping cigarettes, and reduction of caffeine and alcohol.
    • Fainting (Syncope)
      • Fainting, also referred to as blacking out, syncope, or temporary loss of consciousness has many causes. Often a person will have signs or symptoms prior to the fainting episode. Diagnosis and treatment depends upon the cause of the fainting or syncope episode.
    • Heart Attack
      • Heart attack happens when a blood clot completely obstructs a coronary artery supplying blood to the heart muscle. A heart attack can cause chest pain, heart failure, and electrical instability of the heart.
    • Indigestion (Dyspepsia, Upset Stomach)
      • Dyspepsia (indigestion) is a functional disease in which the gastrointestinal organs, primarily the stomach and first part of the small intestine, function abnormally. It is a chronic disease in which the symptoms fluctuate infrequency and intensity. Symptoms of dyspepsia include upper abdominal pain, belching, nausea, vomiting, abdominal bloating, early satiety, and abdominal distention (swelling). These symptoms are most often provoked by eating.
    • Scleroderma
      • Scleroderma is an autoimmune disease of the connective tissue. It is characterized by the formation of scar tissue (fibrosis) in the skin and organs of the body, leading to thickness and firmness of involved areas. Scleroderma is also referred to as systemic sclerosis, and the cause is unknown. Treatment of scleroderma is directed toward the individual features that are most troubling to the patient.
    • Atrial Fibrillation
      • Atrial fibrillation is an abnormality in the heart rhythm which involves irregular and often rapid beating of the heart.
    • Polycythemia (High Red Blood Cell Count)
      • Polycythemia (elevated red blood cell count) causes are either primary (aquired or genetic mutations) or secondary (diseases, conditions, high altitude). Treatment of polycythemia depends on the cause.
    • Abnormal Heart Rhythms (Heart Rhythm Disorders)
      • Heart rhythm disorders vary from minor palpitations, premature atrial contractions (PACs), premature ventricular contractions (PVCs), sinus tachycardia, and sinus brachycardia, to abnormal heart rhythms such as tachycardia, ventricular fibrillation, ventricular flutter, atrial fibrillation, atrial flutter, paroxysmal supraventricular tachycardia (PSVT), Wolf-White-Parkinson syndrome, brachycardia, or heart blocks. Treatment is dependant upon the type of heart rhythm disorder.
    • Heart Disease
      • Heart disease (coronary artery disease) is caused by a buildup of cholesterol deposits in the coronary arteries. Risk factors for heart disease include smoking, high blood pressure, heredity, diabetes, peripheral artery disease, and obesity. Symptoms include chest pain and shortness of breath. There are a variety of tests used to diagnose coronary artery disease. Treatment includes life-style changes, medications, procedures, or surgery.
    • Pericarditis
      • Pericarditis is the inflammation of the pericardial sac that surrounds the heart. The causes of pericarditis include injury from heart attack, heart surgery, trauma; viral or fungal infection, HIV, tumors, mixed connective tissue disease, metabolic disease, medication reactions, or idiopathic. Treatment for pericarditis is generally medication, however, sometimes surgery is necessary.
    • Heart Murmur
      • A heart murmur is the sound generated when blood flow within the heart is not smooth. Causes of heart murmurs can be functional, congenital, or caused heart valve conditions. Symptoms of a heart murmur may be none, or may include chest pain, shortness of breath, and arm, leg, and ankle swelling. Treatment of a heart murmur depends on the cause.
    • Coma
      • Coma is the inability to waken or react to the surrounding environment. The Glasgow Coma Scale is frequently used to measure the depth of coma. Causes of coma include trauma, bleeding, edema, lack of oxygen, poisoning, or hypoglycemia. Prognosis for a patient in a coma depends on the cause of the coma.
    • Transient Ischemic Attack (TIA, Mini-Stroke)
      • When a portion of the brain loses blood supply, through a blood clot or embolus, a transient ischemic attack (TIA, mini-stroke) may occur. If the symptoms do not resolve, a stroke most likely has occurred. Symptoms of TIA include: confusion, weakness, lethargy, and loss of function to one side of the body. Risk factors for TIA include vascular disease, smoking, high blood pressure, high cholesterol, and diabetes. Treatment depends upon the severity of the TIA, and whether it resolves.
    • Kawasaki Disease
      • Kawasaki disease is a rare children's disease characterized by a fever that lasts more than five days and at least four of the following five symptoms are present: rash, swollen neck lymph gland, red tongue, swelling or redness of the hands or feet, and conjunctivitis. High doses of aspirin are used to treat Kawasaki disease. Cortisone and antiinflammatory drugs may also be used during treatment.
    • Orthostatic Hypotension
      • Orthostatic hypotension symptoms include lightheadedness, weakness, blurred vision, and syncope or passing out. Causes of orthostatic hypotension include dehydration, anemia, medication, blood loss, low blood pressure, heat related illnesses and more. Treatment of orthostatic hypotension depends on the underlying cause.
    • Fatigue
      • Fatigue can be described in various ways. Sometimes fatigue is described as feeling a lack of energy and motivation (both mental and physical). The causes of fatigue are generally related to a variety of conditions or diseases for example, anemia, mono, medications, sleep problems, cancer, anxiety, heart disease, drug abuse, and more. Treatment of fatigue is generally directed toward the condition or disease that is causing the fatigue.
    • Hypercalcemia (Elevated Calcium Levels)
      • Hypercalcemia is a condition in which calcium levels in the blood are elevated. Hypercalcemia is associated with other conditions such as hyperparathyroidism, lung cancer, breast cancer, kidney failure, and elevated levels of vitamin D. Symptoms of hypercalcemia include constipation, nausea, abdominal pain, kidney stones, to name a few. Treatment depends on the cause of hypercalcemia.
    • Rheumatic Fever
      • Rheumatic fever is a disease that sometimes occurs after a group A streptococcal infection of the throat. Symptoms and signs include carditis, polyarthritis, Aschoff bodies, rash, Sydenham's chorea, and fever. Treatment for rheumatic fever involves eliminating the bacteria with penicillin, erythromycin, or azithromycin. Further treatment focuses on alleviating the symptoms brought on by the body's immunologic response to the bacteria.
    • Aortic Dissection
      • Aortic dissection is a small tear in the large blood vessel that leads from the heart and supplies blood to the body. There are two types of aortic dissection, type 1 and type 2. Signs and symptoms of aortic dissection include a tearing or ripping pain, nausea, sweating, weakness, shortness of breath, sweating, or fainting. Treatment depends on the type of aortic dissection, and the severity of the tear in the aorta.
    • Diphtheria
      • Diphtheria is an infectious disease caused by the Corynebacterium diphtheriae bacteria. The disease is transmitted via contact with airborne droplets or direct contact with skin lesions. Symptoms and signs include fever, sore throat, hoarseness, difficulty swallowing and breathing. Antibiotics and the diphtheria antitoxin are used in the treatment of diphtheria.
    • Shock (Medical)
      • Medical shock is a life-threatening medical condition. There are several types of medical shock, septic shock, anaphylactic shock, cardiogenic shock, hypovolemic shock, and neurogenic shock. Causes of shock include heart attack, heart failure, heavy bleeding (internal and external), infection, anaphylaxis, spinal cord injury, severe burns, chronic vomiting or diarrhea. Low blood pressure is the key sign of sock. Treatment is dependant upon the type of shock.
    • Paroxysmal Supraventricular Tachycardia (PSVT)
      • Paroxysmal supraventricular tachycardia (PSVT) is an abnormal conduction of electricity in particular areas of the heart. PSVT was referred to at one time as paroxysmal atrial tachycardia or PAT, however, the term PAT is reserved for as specific heart condition. Symptoms of PSVT include weakness, shortness of breath, chest pressure, lightheadedness, and palpitations. PSVT is treated with medications or procedures that return the heart to its normal electrical pattern.
    • See All Related Diseases & Conditions »
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Electrocardiogram (ECG or EKG)

Shock facts

  • Shock is a life-threatening medical condition and is a medical emergency. If shock is suspected call 911 or get to an emergency department immediately.
  • The main symptom of shock is low blood pressure. Other symptoms include rapid, shallow breathing; cold, clammy skin; rapid, weak pulse; dizziness, fainting, or weakness.
  • There are several types of shock: septic shock caused by bacteria, anaphylactic shock caused by hypersensitivity or allergic reaction, cardiogenic shock from heart damage, hypovolemic shock from blood or fluid loss, and neurogenic shock from spinal cord trauma.
  • Treatment for shock depends on the cause. Tests will determine the cause and severity. Usually IV fluids are administered in addition to medications that raise blood pressure.
    • Septic shock is treated with antibiotics and fluids.
    • Anaphylactic shock is treated with diphenhydramine (Benad...

Read the Shock (Medical) article »







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