Click on a highlighted category to view a list of common medical terms. Clicking on the term will reveal the definition. The entire glossary may also be downloaded by clicking on the above print icon.
A document you create to designate who will make healthcare decisions and states your wishes if you become unable to make your own healthcare decisions.
(arrhythmogenic right ventricular cardiomyopathy or arrhythmogenic ventricular dysplasia ARVD or right ventricular cardiomyopathy ) A form of cardiomyopathy in which the heart muscle cells become disorganized and are replaced by fatty tissue.
Asymmetrical septal hypertrophy. This term has been replaced by the current term, hypertrophic cardiomyopathy, because the hypertrophy can occur in any part of the lower heart.
Disease in which fatty deposits build up on the inner walls of the
arteries and cause inflammation which causes narrowing or blockage that can lead to a heart attack; commonly known as "hardening of the arteries".
A fatty substance that comes mostly from eating certain foods which your body uses for normal regulation of cells; when too much cholesterol builds up in the body, it can lead to atherosclerosis.
The percentage of total blood pumped out of the heart during one beat. It is the amount of blood pumped out divided by the amount of blood remaining in the heart at the end of one beat.
A change in mental condition, which can be the result of many things including toxins that normally circulate in the bloodstream that are not cleared properly by the liver and alter brain function.
What happens when the heart cannot supply the body with enough oxygen in the blood to stay healthy. Heart failure can result when muscle cells are abnormal or overworked.
The heart's electrical charges are delayed or do not pass from the uppers chambers to the lower chambers; it is classified according to the level of impairment - first-degree heart block, second-degree heart block, or third-degree (complete) heart block.
Idiopathic hypertrophic subaortic stenosis, a form of hypertrophic cardiomyopathy where the hypertrophy is located under the aortic valve and creates a narrowing (stenosis) that makes it difficult for blood to exit the heart.
Insufficient blood to an organ, caused by narrowing of an artery from blockage, spasm of the wall of the artery, or compression from muscle surrounding the artery.
Type of white blood cell formed in lymphatic tissue; lymphocytes normally comprise about 25% of all white blood cells and play a key role in triggering the body's immune response.
An accumulation of fluid in the pericardial sac, the outer covering of the heart, which, if large, may need to be drained with a needle (pericardiocentesis).
A disorder that occurs after the Fontan Procedure and results in loss of protein molecules from the blood into the intestine and can cause diarrhea. If enough protein is lost, the low protein levels in the blood lead to leakage of fluid into the tissues, causing swelling of the abdomen, face and legs.
A natural or artificially created passageway that connects one part of the circulation to another. Shunts are often used to create more blood flow to the lungs by directing blood from the aorta to the pulmonary artery.
Pertaining to different gene constitutions within the same species, antigenically distinct (i.e. a heart transplant from a genetically different human donor).
Detects a mutation in a gene known to cause a particular disorder. Direct DNA analysis can be accomplished when the gene in question is known and the genetic changes can be found and interpreted.
Biochemical molecule that makes up our genes; it encodes the genetic information necessary for the organization and functioning of most living cells and controls the inheritance of characteristics.
Basic units of heredity consisting of segments of DNA; genes code for specific proteins that perform the functions of the body and lead to particular characteristics.
Takes a microscopic picture of the chromosomes in order to reveal the size, shape, and number of chromosomes in the cells. This method can detect large extra, missing, or abnormal positions of chromosome pieces. Not all genetic abnormalities can be detected by a karyotype.
"A gene-hunting technique" which maps genes for disease in relation to their positions along the chromosome in order to locate a disease-causing mutation specific to a family. This test requires several members of a family with a high risk for a genetic condition and can be used when the exact location of the mutation is unknown. This type of testing is usually performed in research laboratories.
Angiotensin Converting Enzyme (ACE) inhibitors are a group of drugs used to dilate blood vessels and make it easier for the heart to pump blood. They have also been shown to block some of the hormones in the blood that are known to worsen heart failure. Common ACE inhibitors include captopril, enalapril, lisinopril, monopril. Common side effects include high potassium in the blood, low blood pressure, low white blood cell count, and kidney or liver abnormalities.
A medicine that lowers blood pressure and decreases the workload on the heart. ACE inhibitors, described above, are a class of afterload-reducing medications.
A weak diuretic (water pill) that prevents urinary potassium loss; also used to block a kidney hormone (aldosterone) to decrease scar formation within the heart muscle.
Drug designed to block the effects of angiotensin which will help to dilate blood vessels and allow the heart to pump against lower resistance (more dilated) blood vessels. Common examples are Losartan, valsartan, candesartan. Common side effects include diarrhea, muscle cramps, dizziness, and elevated blood potassium and kidney abnormalities.
A blood-thinning medication given to help prevent blood clots from forming in the heart or blood vessels. There is a risk of clots forming inside the heart of children whose heart does not contract well. Anticoagulation medications, also known as blood thinners, prevent blood clotting. Some drugs such as warfarin (coumadin), heparin or enoxaparin, act by inhibiting the activation of clotting factors. These drugs require careful monitoring with regular blood testing. Other drugs act by inhibiting clot-forming cells (platelets) and include aspirin and dipyridamole.
Medications that block high levels of adrenaline in the blood stream to help improve the strength of the heart muscle. Beta-blockers slow the heartbeat and reduce the work of contraction of the heart muscle. Slowing the heart rate can help keep a weakened heart from overworking. In some cases, beta-blockers allow an enlarged heart to become more normal in size. Common beta-blockers include atenolol, carvedilol, metoprolol and nadolol. Common side effects include dizziness, low heart rate, low blood pressure and fluid retention.
(also known as calcium antagonists): Improve the filling of the heart by reducing the stiffness of the heart muscle. These are used in patients with chest pain or
breathlessness. Calcium channel blockers can cause excessive slowing of the heart rate and lower
blood pressure. Common calcium channel blockers are verapamil and diltiazem. Calcium channel blockers are not commonly used in patients with DCM, as they may make the heart failure worse.
A drug (ACE-inhibitor) used to treat high blood pressure and heart failure. It decreases the levels of certain chemicals that act to tighten the blood vessels, so blood flows through more dilated blood vessels at lower pressure which allows the heart to pump using less energy, thereby reducing its workload.
A medicine given to increase the strength of heart contraction or slow down the heart rate. Used appropriately in patients with normal kidney function, side effects are minimal. Drug toxicity can cause vomiting, abnormally slow heart beat, and abnormal conduction.
Medications that help the kidneys pass more water, so reducing excess fluid in the organs, especially the lungs. Diuretics, sometimes called "water pills," reduce excess fluid in the lungs or other organs by increasing urine flow. The loss of excess fluid reduces the workload of the heart, reduces swelling of the legs and liver and helps children breathe more easily. Diuretics can be given either orally or intravenously.
Dobutamine, dopamine, epinephrine, norepinephrine : Sympathomimetic agents that are
given by a continuous intravenous infusion used to increase blood pressure and the strength of
heart contractions. Common side effects include increased heart rate, arrhythmias and for
some, depending on the dose, excessive constriction of the arteries.
Are used to help the heart contract more vogorously. Intravenous ionotropic medications are used to support children who have severe heart failure and do not respond adequately to oral medications.
Phosphodiesterase inhibitor that improves heart contraction and decreases the
work of the heart by relaxing the arteries. A common side effect is low blood pressure.
A drug used to keep the ductus arteriosus open which may be necessary in certain forms of congenital heart disease (i.e. hypoplastic left heart syndrome, critical aortic stenosis, and severe coarctation of the aorta or pulmonary atresia).
Weak diuretic (aka aldactone) that prevents potassium wasting in the urine (helps maintain normal blood potassium level when on other diuretics like lasix).
Blood hormone that increases blood pressure and improves blood flow to the central organs (heart, lungs, brain). Common side effects include excessive constriction of the arteries, low sodium and decreased blood flow to the kidneys and bowel.
An X-ray movie of blood as it moves through the heart and blood vessels after contrast (dye) is injected through a catheter positioned in the heart or nearby blood vessels.
Helps to examine the blood vessels and chambers of the heart. Dye that is visible on an X-ray is injected through the catheter. The flow of the dye can be followed on a video monitor and recorded. The movement of the dye is tracked to assess for "holes" in the heart, abnormal blood pathways through the heart or narrowed blood vessels near the heart.
A tube which is put into the heart via a vein or artery. It is used to help diagnosis by measuring pressures very accurately, or can treat a problem such as widening an artery or closing a hole.
An invasive procedure that involves inserting a thin, flexible, plastic tube (catheter), through a tiny incision in the skin, into a blood vessel (either in the neck or in the groin area) and threading it into the heart or the coronary arteries. The catheterization approach can be used for a range of diagnostic and therapeutic procedures, including measuring blood pressure within the heart and the amount of oxygen that is in the blood in each chamber, as well as determining the pumping ability of the heart muscle.
Uses a small amount of radiation to take a picture of the heart and lungs. Chest X-rays show the size and shape of the heart, the major blood vessels and bones in the chest, and whether there is any fluid present or any abnormalities in the lungs. X-rays can be done at the bedside if the patient cannot be moved safely but are usually performed in the radiology department of the hospital and take just a few minutes to complete.
Performed as part of the echocardiogram and measures the speed and direction of blood through the valves and chambers of the heart as well as the blood vessels taking blood to or away from the heart.
Short for echocardiogram. An echocardiogram uses high frequency sound waves to produce moving images of the beating heart on a video screen. The echocardiogram usually lasts about 45 minutes to an hour. These images allow the cardiologist to measure muscle thickness, pumping ability, chamber size, and valve movement. Pressures inside the heart chambers and major vessels can also be estimated. The study may be done with the use of oral sedation to help optimize study quality especially in uncooperative children under age 2 years.
Tests for abnormal electrical conduction pathways which increase susceptibility to arrhythmias, the effectiveness of anti-arrhythmic drugs, and the need for an implantable cardioverter defibrillator. The study uses fine wires inserted through veins in the groin area and threaded to the heart - a similar approach to cardiac catheterization. Electrical stimuli are applied through these wires to map the hearts' electrical system and susceptibility to abnormal rhythms.
Test done in the outpatient setting to evaluate the heart's reserve while the patient is exercising, usually walking on a treadmill or pedaling a stationary bike. The child's blood pressure, heart rhythm, oxygen saturation and breathing are measured during different degrees of exertion.
Records the heart rhythm continuously for 24 hours on a cassette tape. The test is used when an abnormal heart rhythm is suspected. Your child will wear the monitor home and take it off 24 hours later.
Uses radio waves inside a large magnet to generate a 3-
dimensional image which allows doctors to evaluate the heart and blood vessel anatomy, function, and flow dynamics. This is a non-invasive test and does not involve the use of X-rays. Sometimes sedation is required since patient movement can cause image artifact. A typical MRI takes about 45-60 minutes to complete.
(Multiple Gated Acquisition or radionuclide ventriculogram): Similar to an
echocardiogram, but offers a more accurate measurement of how well the heart functions as a
pump through the use of injected radioactive contrast material. It measures how much blood the heart pumps, or "ejects," with each contraction and how quickly that blood is ejected.
Measures lung function. A child breathes into a tube attached to a measuring device that shows how well the lungs work and often times compliments an exercise stress test. Sometimes PFTs are done with bronchodilators (i.e. albuterol inhaler) to see if these agents improve lung function.
Removal of small piece of body muscle for laboratory analysis. This is a surgical procedure and muscle is usually taken from the leg (in small children) or arm.
Allows doctors to see how the blood flows through the heart muscle. Thallium is a radioactive substance that only travels to the heart muscle cells receiving blood, thereby identifying areas of the heart that at high risk for a heart attack. The thallium is injected through an intravenous line. The test is usually performed in two stages, one during exercise on a treadmill and one at rest. This allows doctors to see how blood flows through the heart while working hard (on the treadmill) and when resting. Aside from the injection, this is a non-invasive test. The imaging can take up to 25 minutes. However, because it takes time for the thallium to circulate, the entire test may take upwards of five hours.
The transplant of an organ or tissue from one individual to another of the same species with a different genotype. A transplant from one person to another, but not an identical twin, is an allograft.
Electric current or radio-frequency energy can be used via a catheter to destroy tissue in the heart which is causing an arrhythmia (abnormal heart rhythm).
Using a tube (catheter) to reach a narrow (stenosed) part of the heart such as an artery or valve and making it bigger by inflating a balloon on the end of the catheter.
A tube (catheter) is put into the heart and a balloon inflated on the end of it to make a hole, or increase the size of a hole, in the wall (septum) of the heart.
Hollow, flexible drainage tubes used to drain away fluid, blood or air from the space between the lungs and the chest wall (the pleural space) and allow full expansion of the lungs.
(extracorporeal membrane oxygenation) : A by-pass machine which can be used as a short-term cardiac assist device used either to rest the heart until it recovers or to support the circulation for the critically ill child waiting for a donor heart. This device is similar to the cardiopulmonary bypass machine used during open-heart surgery. It mechanically pumps oxygenated blood into the circulation and helps circulate blood through the body.
The superior vena cava, which normally brings blood back to the right side of the heart, is connected to the pulmonary artery, so the venous blood is delivered directly to the lungs, bypassing the right ventricle.
(implantable cardioverter-defibrillator) : An electronic device installed inside the body to provide an electrical "shock(s)" to the heart to stop an abnormal fast heart rhythm and return the heart to a normal rhythm. Also known as an AICD (automatic implantable cardioverter defibrillator.
Are specifically designed to take over the function of the heart's left ventricle, while BiVentricular Assist Devices (BIVADs) offer support for both ventricles. In one type of LVAD, the pumping device is surgically implanted in the chest, while the battery and controller remain outside the body (external), worn on a belt. A tube placed in the left ventricle diverts blood from the heart to the pump. The pump then propels the blood back into the aorta - with enough force to be distributed adequately throughout the body.
Involves the removal and examination of a piece of muscle tissue or
skin cells. This tissue is sent to a pathologist for microscopic examination. Muscle biopsy plays
an integral role in the evaluation of the person with neuromuscular disease.
A small battery-powered implantable device (generator) placed under the skin and joined to the heart by wires, which electrically stimulates the heart to contract and pump blood throughout the body. The wires (leads) are either connected directly to the surface of the heart (epicardial leads) or threaded through veins into the heart (transvenous leads). The devices monitor the heartbeat and help the heart to beat in a regular rhythm. Small electrical charges travel from the pacemaker, through the wire, to an electrode placed in the heart wall.
A medical device (pacemaker) designed to regulate the electrical activity of the heart. It either stimulates or regulates the hearts electrical activity when the rate is not fast enough.
A surgery that is performed to remove thickened muscle of the septum (the wall dividing the two sides of the heart) when that muscle has narrowed the pathway from the ventricle into the aorta obstructing the blood flow from the heart.