Pacemaker Glossary of Terms

Abdomen: The belly , that part of the body that contains all of the structures between the chest and the pelvis . The abdomen is separated anatomically from the chest by the diaphragm , the powerful muscle spanning the body cavity below the lungs .
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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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Aging: The process of becoming older, a process that is genetically determined and environmentally modulated.
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Anesthesia: Loss of feeling or awareness. A general anesthetic puts the person to sleep. A local anesthetic causes loss of feeling in a part of the body such as a tooth or an area of skin without affecting consciousness. Regional anesthesia numbs a larger part of the body such as a leg or arm, also without affecting consciousness. The term "conduction anesthesia" encompasses both local and regional anesthetic techniques. Many surgical procedures can be done with conduction anesthesia without significant pain. In many situations, such as a C-section, conduction anesthesia is safer and therefore preferable to general anesthesia. However, there are also many types of surgery in which general anesthesia is clearly appropriate.

Anesthetic: A substance that causes lack of feeling or awareness. A local anesthetic causes loss of feeling in a part of the body. A general anesthetic puts the person to sleep.

Arm: 1. In popular usage, the appendage that extends from the shoulder to the hand. However, the medical definition refers to the upper extremity extending from the shoulder only to the elbow, excluding the forearm, which extends from the elbow to the wrist. The arm contains one bone: the humerus. 2. In a randomized clinical trial, any of the treatment groups. Most randomized trials have two "arms," but some have three "arms," or even more.

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 arrhythmias: See: Arrhythmias, atrial.

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

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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Breathing: The process of respiration, during which air is inhaled into the lungs through the mouth or nose due to muscle contraction, and then exhaled due to muscle relaxation.

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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Cardiologist: A doctor who specializes in treating heart disorders.

Cardiovascular: The circulatory system comprising the heart and blood vessels which carries nutrients and oxygen to the tissues of the body and removes carbon dioxide and other wastes from them.
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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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Chronic: This important term in medicine comes from the Greek chronos, time and means lasting a long time.
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Collarbone: A horizontal bone above the first rib that makes up the front part of the shoulder.
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Complication: In medicine, an additional problem that arises following a procedure, treatment or illness and is secondary to it. A complication complicates the situation.
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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.

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.)
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Congenital heart disease: A malformation of the heart or the large blood vessels near the heart. The term "congenital" speaks only to time, not to causation; it means "born with" or "present at birth."
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Congestive 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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Contraction: The tightening and shortening of a muscle.

Defibrillator: A device used to correct a dangerously abnormal heart rhythm, usually ventricular fibrillation, or to restart the heart by depolarizing its electrical conduction system and delivering brief measured electrical shocks to the chest wall or the heart muscle itself.

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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Ear: The hearing organ. There are three sections of the ear, according to the anatomy textbooks. They are the outer ear (the part we see along the sides of our head behind the temples), the middle ear, and the inner ear. But in terms of function, the ear has four parts: those three and the brain. Hearing thus involves all parts of the ear as well as the auditory cortex of the brain. The external ear helps concentrate the vibrations of air on the ear drum and make it vibrate. These vibrations are transmitted by a chain of little bones in the middle ear to the inner ear. There they stimulate the fibers of the auditory nerve to transmit impulses to the brain.
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Electrophysiology: The biomedical field dealing with the study of electric activity in the body. Electrophysiology includes the study of the production of electrical activity and the effects of that electrical activity on the body. See, for example: Electrophysiologic retinal testing ; and Electrophysiologic study of the heart.

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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Glucose: The simple sugar (monosaccharide) that serves as the chief source of energy in the body. Glucose is the principal sugar the body makes. The body makes glucose from proteins, fats and, in largest part, carbohydrates. Glucose is carried to each cell through the bloodstream. Cells, however, cannot use glucose without the help of insulin . Glucose is also known as dextrose.
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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 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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Implant: 1. To embed; to set in firmly. In embryology, the fertilized egg implants in the uterine lining 6 or 7 days after conception (fertilization). In medicine today, many things may be implanted.
2. That which is embedded. For example: lens implants, breast implants, cochlear implants, defibrillator implants, pacemaker implants, etc.

Implantation: The act of setting in firmly.
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Incision: A cut. When making an incision, a surgeon is making a cut.

Infection: The growth of a parasitic organism within the body. (A parasitic organism is one that lives on or in another organism and draws its nourishment therefrom.) A person with an infection has another organism (a "germ") growing within him, drawing its nourishment from the person.
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Injure: To harm, hurt, or wound. The word injure may be in physical or emotional sense. Treadmill machines may injure anyone who gets on one. Sexual molestation injures children. From the Latin injuria meaning injury.

Kidney: One of a pair of organs located in the right and left side of the abdomen which clear "poisons" from the blood, regulate acid concentration and maintain water balance in the body by excreting urine. The kidneys are part of the urinary tract. The urine then passes through connecting tubes called "ureters" into the bladder. The bladder stores the urine until it is released during urination.

Laboratory: A place for doing tests and research procedures and preparing chemicals, etc. Although "laboratory" looks very like the Latin "laboratorium" (a place to labor, a work place), the word "laboratory" came from the Latin "elaborare" (to work out, as a problem, and with great pains), as evidenced by the Old English spelling "elaboratory" designating "a place where learned effort was applied to the solution of scientific problems."
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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.

Lightheadedness: A feeling you are "going to faint." Lightheadedness is medically distinct from dizziness, unsteadiness, and vertigo. See: Dizziness, Unsteadiness, and Vertigo.

Liver: An organ in the upper abdomen that aids in digestion and removes waste products and worn-out cells from the blood. The liver is the largest solid organ in the body. The liver weighs about three and a half pounds (1.6 kilograms). It measures about 8 inches (20 cm) horizontally (across) and 6.5 inches (17 cm) vertically (down) and is 4.5 inches (12 cm) thick.

Lungs: The lungs are a pair of breathing organs located with the chest which remove carbon dioxide from and bring oxygen to the blood. There is a right and left lung.

Magnetic resonance imaging : A special radiology technique designed to image internal structures of the body using magnetism, radio waves, and a computer to produce the images of body structures. In magnetic resonance imaging (MRI), the scanner is a tube surrounded by a giant circular magnet. The patient is placed on a moveable bed that is inserted into the magnet. The magnet creates a strong magnetic field that aligns the protons of hydrogen atoms, which are then exposed to a beam of radio waves. This spins the various protons of the body, and they produce a faint signal that is detected by the receiver portion of the MRI scanner. A computer processes the receiver information, and an image is produced. The image and resolution is quite detailed and can detect tiny changes of structures within the body, particularly in the soft tissue, brain and spinal cord, abdomen and joints.
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Malaise: A vague feeling of discomfort, one that cannot be pinned down but is often sensed as "just not right."
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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).
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MRI: Abbreviation and nickname for magnetic resonance imaging. For more information, see: Magnetic Resonance Imaging; Paul C. Lauterbur; Peter Mansfield.

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."

Nerve: A bundle of fibers that uses chemical and electrical signals to transmit sensory and motor information from one body part to another. See: Nervous system.

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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Operating room: A facility equipped for performing surgery. Abbreviated OR.

Organ: A relatively independent part of the body that carries out one or more special functions. The organs of the human body include the eye, ear, heart, lungs, and liver.

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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Pill: In pharmacy, a medicinal substance in a small round or oval mass meant to be swallowed. Pills often contain a filler and a plastic substance such as lactose that permits the pill to be rolled by hand or machine into the desired form. The pill may then be coated with a varnishlike substance.
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Race: An ethnic stock or division of humans. Naturalists and ethnographers have long divided humans into a variable number of distinct races. However, DNA and other genetic studies have revealed that that most genetic variation, about 94%, is within so-called racial groups while these racial groupings differ from one another only in about 6% of their genes. This means that there is greater genetic variation within racial groups than between them. The concept of race is a superficial and subjective one. All of humankind is a single species.

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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Recurrent: Back again. A recurrent fever is a fever that has returned after an intermission: a recrudescent fever.

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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Scan: As a noun, the data or image obtained from the examination of organs or regions of the body by gathering information with a sensing device.
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Sick sinus syndrome: Symptoms of dizziness , confusion, fainting , and heart failure due to a problem with the sinus node of the heart, which acts as the body's natural pacemaker . If the sinus node is not functioning normally, it is reflected in an abnormally slow heart rate (bradycardia). This can cause poor pumping by the heart, which can impair the circulation.
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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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Skin: The skin is the body's outer covering. It protects us against heat and light, injury, and infection. It regulates body temperature and stores water, fat, and vitamin D. Weighing about 6 pounds, the skin is the body's largest organ. It is made up of two main layers; the outer epidermis and the inner dermis.

Spine: 1) The column of bone known as the vertebral column, which surrounds and protects the spinal cord. The spine can be categorized according to level of the body: i.e., cervical spine (neck), thoracic spine (upper and middle back), and lumbar spine (lower back). See also vertebral column. 2) Any short prominence of bone. The spines of the vertebrae protrude at the base of the back of the neck and in the middle of the back. These spines protect the spinal cord from injury from behind.

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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Stroke : The sudden death of some brain cells due to a lack of oxygen when the blood flow to the brain is impaired by blockage or rupture of an artery to the brain. A stroke is also called a cerebrovascular accident or, for short, a CVA.
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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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Syndrome: A set of signs and symptoms that tend to occur together and which reflect the presence of a particular disease or an increased chance of developing a particular disease.
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Temperature: The temperature is the specific degree of hotness or coldness of the body. It is usually measured with a thermometer.
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Tiredness: See: Tired.

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.

Virus: A microorganism smaller than a bacteria, which cannot grow or reproduce apart from a living cell. A virus invades living cells and uses their chemical machinery to keep itself alive and to replicate itself. It may reproduce with fidelity or with errors (mutations)-this ability to mutate is responsible for the ability of some viruses to change slightly in each infected person, making treatment more difficult.
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From the Doctors at MedicineNet.com

Low Blood Pressure - Learn about low blood pressure (hypotension). Low blood pressure is blood pressure below normal and symptoms may include: lightheadedness, dizziness, fainting upon standing (orthostatic hypotension). There are many causes of low blood pressure, and treatment is dependant upon the cause. Source:MedicineNet Aspirin, Beta blockers, and Ace Inhibitors - Heart attacks can be prevented through medications such as aspirin, anti-platelet meds, beta blockers and ace inhibitors Source:MedicineNet Ventricular Septal Defect - Read about diagnosis, symptoms, prognosis, complications and treatment of ventricular septal defect (VSD), a congenital defect in which there's a hole in the heart's wall. Source:MedicineNet Read 101 more Pacemaker related articles ... Health Tip: Living With a Pacemaker New Guidelines Issued for Implanted Heart Devices Heart Device Recipients Often Not Aware of Recalls Pacemakers Change Biology of the Heart Health Tip: How a Pacemaker Helps the Heart Drug, Pacemaker Fight Irregular Heartbeat Defibrillators Not Dangerous While Driving IPods Don't Interfere With Pacemakers, Study Shows IPods Don't Interfere With Heart Pacemakers New Heart Pump Helps Women Awaiting Transplants