| A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z |

Acquired Heart Disease - Disease of the heart that develops after birth, due to an infection or other disease affecting the heart muscle, heart valves or coronary arteries (compare with 'Congenital Heart Disease').

Antibiotics  - A medicine, which may be taken by mouth as a syrup, tablet or capsule, or may be given through a drip into a vein, to prevent or treat a bacterial infection.

Anticoagulant  -  A drug used to reduce blood clotting, e.g. warfarin, aspirin.

Aorta - The main artery which takes blood from the heart into the circulation around the body (systemic circulation).

Aortic Atresia - Complete obstruction to the aortic valve or the aorta (usually associated with Hypoplastic Left Heart Syndrome)

Aortic Stenosis  - Narrowing of the aortic valve resulting from a congenital defect of the valve leaflets or disease of the valve.

Aortic Valve - The valve at the origin of the aorta, which controls flow of blood out of the heart and prevents backflow.

Arrhythmia - A disturbance in the normal heart rhythm.

Aterial Valve- One of the valves which control flow from the ventricles into the circulation, during each heart beat, and prevent backflow. (see 'Aortic Valve' and 'Pulmonary Valve').

Artery - A blood vessel which carries blood away from the heart. Usually the blood is oxygenated, except in the pulmonary arteries which carry deoxygenated blood to the lungs.

Artificial Valves - These are man made substitutes for heart valves, used to replace a defective valve.

ASD - See 'Atrial Septal Defect'.

Atresia - Complete obstruction to a valve or blood vessel, so that blood cannot get past this point in the circulation and has to take an alternative route.

Atrial Septal Defect (ASD)  -  A defect (hole) in the atrial septum which allows blood to shunt from one atrium to the other.

Atrial Septum  - The septum (partition or wall) between the two atriums.

Atrioventricular - Relating to the junction between the atriums and the ventricles of the heart.

Atrioventricular Septal Defect  (AV Canal Defect)  -  A defect (hole) involving both the atrial and ventricular septums. The mitral and tricuspid valves are also abnormal.

Atrioventricular Valve  - One of the valves which control blood flowfrom the atriums to the ventricles, and prevent backflow. (see 'Mitral Valve' and 'Tricuspid Valve').

Atrium  - One of the two bloodcollecting (reservoir) chambers at the top of the heart; (plural = atria or atriums).

AV Canal Defect  - See 'Atrioventricular Septal Defect'.

Banding - An operation which involves placing a band of narrow tape around the main pulmonary artery to reduce blood flow and pressure in the lungs. This is a temporary operation used to alleviate the effects of some heart problems . The banding delays the need for further heart surgery until a more appropriate time, e.g. allowing time for the baby to grow.

Blood Tests - Many blood tests may be needed before and after heart surgery, or at other times. They may include blood counts to detect anaemia or infection, or chemical analysis to detect an imbalance in the blood or build up of harmful acid or waste products. During the early days after surgery and while patients are having drug treatment for congestive heart failure, chemical imbalances in the blood are frequent and may require medications to be altered. Some medicines need to be checked to see how much of it is in the child's blood in order to assess whether the dose needs to be increased or decreased. Other tests may measure the effectiveness of a medication (e.g. anticoagulants). The presence of fever or other indications of possible infection will also need investigation with blood counts or blood cultures.

Blood Pressure - A measure of the pressure with which the heart pumps blood into the circulation, usually referred to by two numbers. The 'systolic' pressure refers to the maximum pressure in the artery during each heart beat, while the 'diastolic' pressure is the minimum pressure between heart beats. The left side of the heart and the arteries are operating as a high pressure system, while the veins, the right side of the heart and the pulmonary circulation operate at a much lower pressure.

Brady - Prefix meaning 'slow'.

Bypass Operation - An operation needing  'Heart Lung Bypass'. This refers to the use of the heart lung bypass machine, which takes over the function of the heart and the lungs, pumping blood round the body and supplying oxygen to the blood. (When people refer to a 'double bypass' or 'triple bypass' operation, etc., they are usually referring to an operation to provide a bypass for blocked coronary arteries, usually in adults with Coronary Heart Disease. This is not the same as a Bypass Operation, although most operations for Coronary Heart Disease do use 'Heart Lung Bypass').

Cannula  - A very small tube introduced into a vein to provide access for a 'drip'

Capillary - A microscopic blood vessel connecting arteries to veins. The blood constituents seep through these tiny vessels in the systemic (body) circulation and pulmonary (lung) circulation. Their walls are extremely thin and allow oxygen, carbon dioxide, glucose and other chemicals to pass to and fro between the blood and the surrounding cells in the body organs, or air sacs in the lungs.

Cardiac  -  A term for anything to do with the heart (e.g. cardiac muscle, cardiac specialist, cardiac rhythm, etc.).

Cardiomyopathy  -  Damaged or diseased heart muscle.

Catheter (Cardiac)  -  A 'tube' used to perform heart tests, by introducing it through an artery or vein into the heart ( Catheter Tests)

Catheter  -  (Urinary) A 'tube' used to drain urine from the bladder (often used after heart surgery).

Closed Heart Surgery  -  Heart surgery which does not involve operating on the heart's interior and does not need 'heartlung bypass'.

Clubbing  -  Swelling of the tips of the fingers and toes, producing 'finger clubbing' often seen in children who are cyanosed for many years.

Coarctation   - An area of stenosis (narrowing) in an artery (usually the aorta).

Collaterals  -  Alternative pathways taken by blood when the normal route through an artery or vein is blocked or has not developed properly. Because of the obstruction the alternative pathways (collateral's) may increase in size and eventually may become nearly as large as the original artery or vein, which is blocked. In some conditions (e.g. Pulmonary Atresia) large collateral's may form before birth, carrying blood to the lung circulation from the aorta (sometimes referred to as MAPCAs Major Aorto Pulmonary Collateral Arteries).

Conducting Tissue - Specialised cells or pathways in the heart, which transfer the electrical stimulus from the heart's natural pacemaker to the heart muscle of the atriums and ventricles to signal the heart muscle to contract, for each heart beat.

Conduit  - A term referring to a tube used to connect one part of the circulation to another surgically (e.g. to bypass an obstructed valve or blocked artery).

Congenital  - Describes a condition which develops during formation, before birth, and so already exists when a baby is born.

Congenital Heart Disease  -  A defect or disease affecting the heart from birth (compare with 'Acquired Heart Disease').

Congenitally Corrected Transposition of the Great Arteries  -  In this complex malformation, the ventricles are on the opposite side of the heart to usual. The atria are connected to the incorrect ventricles and the great arteries also come from the wrong ventricles (transposition). Despite these problems, blood from the lungs passes to the aorta, so the child is not cyanosed. Other heart defects are commonly present (e.g. VSD, valve abnormalities, coarctation, pulmonary stenosis).

Congestive Heart Failure  -  A condition which occurs when there is a buildup of fluid (i.e. congestion) in the lungs or other organs such as the liver. This congestion usually results when the heart is unable to work efficiently. Children with heart failure may have symptoms such as marked shortness of breath and difficulty with feeding. The term 'heart failure' does not mean that the heart will suddenly stop beating.

Contraction  -  When the muscle in the heart wall works (squeezes) to push the blood through the heart and out into the arteries.

Coronary Arteries  -  These small arteries carry the blood supply to the heart muscle itself, and are the first arteries to branch off the aorta.

Coronary Heart Disease  -  Disease of the coronary arteries usually in adults.

Cross Match  -  The test to ensure that blood, for transfusion, is compatible with the patient and will not cause an unwanted reaction.

Cyanosis  -  The condition of the skin and nails looking a purplish blue colour due to lowered oxygen level in the blood. A child with this condition may be described as being cyanosed.

Defect  - A physical abnormality, e.g. of the position or structure of the heart or main blood vessels.

Dextrocardia  -  A condition in which the heart lies in the right side (instead of the left) of the chest. The heart may be normal or have other defects.

Diastole  -  The time during which the ventricular heart muscle relaxes after each contraction, between each heart beat.

Diastolic Pressure  -  The lowest point of blood pressure in the arteries.

Digoxin  -  A medicine given to strengthen the heart contraction or reduce the heart rate.

DILV  -  See 'Double Inlet Left Ventricle'.

Disease  -  This term may be used by the doctors to describe either a congenital defect or an acquired condition, and their effects.

Diuretics  -  Medicine to help the body to get rid of the excess fluid which may build up in the lungs or elsewhere in the body in congestive heart failure, e.g. aldactone, lasix. It does this by causing the kidneys to increase their production of urine. Other medicine, e.g. potassium, may be given at the same time to maintain the balance of salts in the body, which may tend to be affected adversely by the diuretic.

Donor Valves (Homograft or Cadaver Valves)  -  A heart valve (usually the aortic or pulmonary valve), taken from the heart of a child or adult soon after death, which can be kept sterile and frozen to preserve its structure. It can be used as a replacement for a defective or missing valve in a child or adult having heart surgery.

Double Inlet Left Ventricle (Dilv)  -  A condition in which both atria are connected to the left ventricle. The right ventricle is usually very small.

DORV  -  See 'Double Outlet Right Ventricle'.

Double Outlet Right Ventricle (DORV)   -  A condition where both the aorta and pulmonary artery are connected to the right ventricle. Blood from the left ventricle passes through a VSD to the right ventricle to reach the great arteries.

Drip  - See 'Lntravenous DRIP'.

Ductus  - The blood vessel connecting the aorta with the pulmonary artery before birth. The full name is 'Ductus Arteriosus'. It usually closes within the early days or weeks after birth. If it remains open after this time it is called a Patent (or Persistent) Ductus Arteriosus (PDA).

ECG - See 'Electrocardiogram'.

Echocardiogram (Echo) - An ultrasound scan of the heart. Very high frequency sound waves (ultrasound) are used to create a moving picture of the heart and of blood flowing through it, using a sophisticated computer. This test detects most heart defects and can provide detailed information about the nature and severity of heart problems of many kinds. The test is not painful, but requires that the child remain still for 10 to 20 minutes (sometimes longer). Some children may benefit from mild sedation to help them cooperate during the scan.

Effusion - A collection of fluid in an area such as the pericardium or the pleural cavity. Such a collection, if it is large, may lead to buildup of pressure on the heart or lungs, and often results in deterioration in their function, and so it may need to be drained.

Electrocardiogram (ECG) - A test to measure the heart's electrical activity with each heart beat. Wires are attached to the skin of the arms, legs and chest, using soft, stickon discs (called 'electrodes'). A tracing is printed on paper and gives information about the heart rate and regularity, as well as providing data about enlargement of the heart chambers and thickening of heart muscle, which may provide useful information about the nature and severity of heart problems.

Endocarditis  - An infection of the endocardium, which occurs as Acute (rapid onset) or Sub acute (more gradual onset) Infective Endocarditis. Such infections are much more likely to develop in patients with existing abnormalities of heart valves or other cardiac defects (e.g. VSD or PDA) than in people with entirely healthy hearts, who are regarded as being " at risk" , though they occasionally occur in individuals with no preexisting heart problem.

Endocarditis Prophylaxis - Use of antibiotics to prevent endocarditis at times when bacteria may be expected to enter the bloodstream (e.g. dental extractions or surgery on nose, throat, mouth or bowel). See  Protocol for prevention.

Endocardium - The smooth membrane which lines the inner surface of the heart, the surface of the four heart valves and the inside of the great vessels (aorta and main pulmonary artery).

Fallots Tetralogy  - A common heart defect associated with cyanosis. There are four parts to the defect (Tetra = four). The name 'Fallot' refers to the French doctor who described the features of the defect.

Finger Clubbing - See 'Clubbing'.

Fontan Operation  -  An operation to connect the main veins from the systemic circulation (SVC and IVC) to the lung arteries. Blood then flows directly into the lung circulation, after returning from the body, without going through the right ventricle as would happen in a normal heart. This operation is named after a French surgeon Francis Fontan.

Foramen Ovale - The hole between the two atriums present at birth.

General Practitioner (GP) - Your family doctor. It is helpful to first visit your GP when your heart child is reasonably well. Then, when your child is ill, the doctor can see how skin colour, breathing, heart sounds, etc. have changed.

Haemoglobin - The red blood pigment which carries oxygen in the red blood cells.

Heart Block - A condition in which there is damage to, or a defect or disease affecting the conducting tissue which carries the electrical stimulation for the contractions of the heart. If the condition is 'partial', the heart rhythm may be normal for much of the time, but in more severe forms, especially when 'complete', the heart may beat very slowly and become seriously ineffective. A patient with this problem may need an artificial pacemaker.

Heart Failure - See 'Congestive Heart Failure'.

Heartlung Bypass  - A technique employed for nearly all open heart operations by which the circulation is supported by a machine. The machine takes over the function of both the heart and the lungs (the 'heartlung bypass machine'), while the surgeon opens the heart to perform an operation inside it (see 'Open Heart Operation' And 'Bypass Operation').

Heart Sounds - The sounds (heard normally with the doctor's stethoscope) which result from closure of the heart valves with each heart beat. The two atrioventricular valves (mitral valve and tricuspid valve) close at the beginning of each beat, producing the 'first heart sound'. The two arterial valves (pulmonary valve and aortic valve) close at the end of each heart beat, producing the 'second heart sound'.

Homograft - Usually refers to a replacement heart valve which comes from the heart of a 'donor'. The valve is not subject to rejection and does not require anti-rejection drugs. Such valves may function better than an artificial valve and do not necessitate anti-coagulant medications - but they do not last as well as artificial valves.

Hypo - Prefix meaning smaller or less than usual.

Hypoplastic - Smaller than normal or underdeveloped.

Hypoplastic Left Heart Syndrome- A condition in which the left side of the heart is poorly developed and unable to pump blood into the systemic circulation effectively.

Hypoplastic Right Heart Syndrome - A condition in which the right side of the heart is poorly developed and unable to pump blood into the pulmonary circulation effectively.

Hypotension - Low blood pressure (in the systemic circulation) a problem quite often encountered after heart surgery and may need treatment with medications to raise the blood pressure.

Hyper - Prefix meaning larger or more than usual.

Hypertension  - High blood pressure. The term usually refers to high pressure in the systemic circulation. However 'pulmonary hypertension' means elevation of pressure in the lung circulation.

Hypertrophy - Thickening or enlargement of a structure. (Left ventricular hypertrophy means thickening of the wall of the left ventricle).

ICU - See 'Intensive Care Unit'.

Incompetent - A term used to refer to 'leakage' at a heart valve. The valve is incompetent if it fails to close effectively and does not prevent 'backflow'. The flow of blood backwards through a valve, which should be closed, is referred to as 'regurgitation' or 'incompetence'.

Infection - Occurs when a microorganism which can produce disease invades a living tissue. Inflammation is one of the body's reactions to infection.

Inferior Vena Cava (IVC) - The main vein from the lower part of the body which returns deoxygenated blood to the heart.

Inflammation - Occurs when a living tissue is reacting to an injury or an infection. Swelling, pain or redness in the tissue are signs of inflammation.

Innocent Murmur  -  A murmur heard in healthy children, which does not signify any underlying heart disease or defect. These soft heart murmurs are very common and are of no significance.

Intensive Care Unit (ICU) - The special medical and nursing unit to which patients go for a few hours (or days) after major heart surgery or if they are extremely ill. This area is used to ensure very close monitoring, and ready availability of medical and nursing staff and equipment to cater for any emergency. It is available for seriously ill children, with a wide variety of medical problems, and for those who have had open heart operations, or other major heart surgery, especially if they need 'ventilator' treatment.

Interrupted Aortic Arch  -  A condition in which the upper and lower aorta are completely separated (a severe form of coarctation). A large VSD is nearly always present.

Interventional Procedures - Procedures of this type may be used to stretch open a narrow valve or blood vessel, using a catheter with an inflatable balloon (Illustration). Alternatively, a tiny 'spring coil' may be inserted to block off an abnormal and unwanted blood vessel (Illustration), or an expanding plug (usually referred to as a 'device') may be placed to close a hole such as an ASD or VSD.(Illustration)

Intravenous Drip (IV or Drip) - A method of providing medications, fluids or nutrition into a vein. The fluid usually flows from a polythene bag or bottle and can be seen to 'drip' into a small container (chamber), which is connected by a tube to a cannula in the vein. Most children will have a 'drip' following an anaesthetic or after heart surgery. In small babies and in children who need continuous medications by 'drip', the medications may be given by a motorised syringe pump, which controls the rate of administration very precisely.

IVC  -  See 'Inferior Vena Cava'.

Leaky Valve  -  See 'Incompetent'.

Long QT Syndrome  -  A condition affecting the electrical pathways of the heart.

Mitral Atresia - Complete obstruction to the mitral valve.

Mitral Stenosis - Narrowing of the mitral valve resulting from a congenital defect of the valve leaflets or disease of the valve.

Mitral Valve  - The valve at the junction of the left atrium with the left ventricle, which controls flow of blood into the ventricle, before each beat, and prevents backflow.

Murmur - A noise, heard with the doctor's stethoscope (or occasionally with the naked ear), which results from turbulence (eddies) in the flow of blood through the heart or blood vessels. The noise often has a 'blowing', 'swishing' or 'cooing' character and is quite different from the 'heart sounds' though many normal children have soft murmurs (see 'Innocent Murmur', 'Thrill' and 'Heart Sounds').

Myocarditis - Inflammation of the heart muscle caused by a virus or other illness.

Myocardium - The cardiac muscle.

Nuclear Medicine Scan - A procedure which involves injecting a very tiny dose of a radio isotope (radioactive compound) into a vein and scanning the heart to assess its function or blood flow through it, using a special Xray scanner. The test may give information about heart function, abnormalities in the heart's own blood supply or the significance of septal defects.

Open Heart Operation - An operation which requires that the heart be opened in order to perform surgery inside it. These operations almost always necessitate the use of heart lung bypass.

Pacemaker (Artificial) - An electronic device used to stimulate the heart and regulate the heart rhythm. Many children are attached to a pacemaker temporarily after heart surgery, in case their heart rhythm becomes abnormal. Some children need a permanent artificial pacemaker (often because of heart block), in which case the pacemaker is put in, under the skin in the upper abdomen or in front of an armpit, at an operation.

Paediatrician - A specialist in children's diseases or problems. Some paediatricians are experts in particular types of disease or defects (e.g. Paediatric Cardiologist, or Paediatric Neurologist [specialist in brain and nerve diseases]). Others take a more general interest in the whole development of the child, physically and intellectually, and in a wide range of diseases and problems of infancy and childhood.

Patent - 'Open' (as in Patent Ductus Arteriosus).

Patent Ductus Arteriosus (PDA)  - Refers to the situation when the ductus remains open after the early days or weeks of life, resulting in a shunt of blood between the aorta and the pulmonary artery.

Patent Foramen Ovale (PFO) - A small hole between the atriums, related to failure of the normal Foramen Ovale to close completely after birth. Such a communication is present in about 20% of normal adults and very seldom causes any problem or requires treatment.

PDA  - See 'Patent Ductus Arteriosus'

Pericardial Effusion - A collection of fluid in the pericardium (sac around the heart). Such a collection, if it is large, may lead to a buildup of pressure on the heart. This often results in deterioration in its function, leading to low blood pressure or heart failure.

Pericarditis - Inflammation of the pericardium, usually due to an infection. Can be a cause of chest pain.

Pericardium - The sac surrounding the heart, which normally contains a very thin film of lubricating fluid.

PFO - see 'Patent Foramen Ovale'

Pleura - A term which may refer to either (1 ) visceral pleura a membrane which encloses each lung, or (2) parietal pleura a membrane which lines the inside wall of the chest cavity.

Pleural Cavity - A potential space between the visceral pleura and parietal pleura. This space normally contains a very thin film of lubricating fluid (compare with 'Pleural Effusion' and 'Pneumothorax').

Pleural Effusion - A collection of fluid in the pleural cavity. Such a collection, if it is large, may lead to a buildup of pressure on the affected lung. This often results in deterioration in its function, with breathlessness and a fall in oxygen levels in the blood.

Pneumothorax - Presence of a collection of air in the pleural cavity. It may result from a tiny puncture in the outside wall of the lung or can follow heart or lung surgery. Such a collection, if it is large, may lead to a buildup of pressure on the affected lung. This often results in deterioration in its function, with breathlessness and a fall in oxygen levels in the blood.

Prolapse (of Mitral or Aortic Valve) - Refers to one of the valve leaflets (flaps) being weaker than normal and tending to fall backwards when the valve closes - resulting often in valve regurgitation.

Pulmonary - A term for anything to do with the lungs.

Pulmonary Arteries - The arteries carrying blood into each lung. There are two large branches from the (main) pulmonary artery, ('left pulmonary artery' and 'right pulmonary artery') and many smaller branches within each lung. All these are called 'pulmonary arteries'.

Pulmonary Artery - The main artery carrying blood from the heart to the lungs.

Pulmonary Atresia - Complete obstruction to the pulmonary valve or pulmonary artery.

Pulmonary Stenosis  - Narrowing of the pulmonary valve or artery, resulting from (1 ) a congenital defect of the valve leaflets or disease of the valve, or (2) abnormal development (or damage resulting from previous surgery) of the artery or its branches.

Pulmonary Valve - The valve at the origin of the pulmonary artery, which controls the flow of blood out of the right ventricle and prevents backflow.

Pulse - The 'beat' felt in an artery, for example in the wrist, groin, neck, or other site and measured in beats per minute. It shows the rate at which the heart is beating, or contracting.

Red Blood Cells - The blood cells which carry oxygen.

Regurgitation - See 'Incompetent'.

Respiration - Breathing.

Respirator (Ventilator) - A machine for helping to maintain adequate respiration when the patient is unable to breath adequately on their own.

Respiratory - Anything to do with 'respiration'.

Respiratory Failure - Implies that the lungs are unable to transfer enough oxygen into the blood, resulting in increasing breathlessness and cyanosis. This may be due to many different diseases affecting the lungs, including severe heart failure, which leads to congestion of the lungs (see 'Congestive Heart Failure').

Ross Operation  -  An operation to replace the aortic valve by using the healthy pulmonary valve. The pulmonary valve is itself replaced with a homograft valve.

Septum  -  The wall within the heart separating the left and right sides. The atriums are separated by the 'atrial septum' and the ventricles by the 'ventricular septum'.

Shunt  -  A term which may refer to either (1) blood flow from an area of higher pressure to an area of lower pressure, through an abnormal communication (e.g. septal defect), or (2) a surgically created communication between two blood vessels usually achieved via the insertion of an artificial tube (conduit). This improves the circulation through the lungs, in cyanosed infants or children, who have reduced blood flow in the lungs.

Stenosis - Narrowing (usually of a heart valve or an artery).

Sub - Prefix meaning 'below'.

Sub Aortic Stenosis - Narrowing below the aortic valve. This usually results from the presence of abnormal tissue or muscle below the valve.

Superior Vena Cava (SVC) - The main vein from the upper part of the body which returns deoxygenated blood to the heart.

Supra - Prefix meaning 'above'.

Supra Aortic Stenosis - Narrowing above the aortic valve. This results from narrowing of the aorta just above the valve.

Supra Cardiac - A term which means 'above the heart', as in 'Supra cardiac Total Anomalous Pulmonary Venous Drainage' ( TAPVD) where the lung veins connect above the heart to the SVC.

SVC - See 'Superior Vena Cava'.

Systemic - Something which involves the whole body, e.g. systemic circulation.

Systole - The time during which the ventricular heart muscle contracts to pump blood.

Systolic Blood Pressure - The highest point of blood pressure in the arteries.

Tachy - Prefix meaning 'fast'.

Tachycardia - A fast heart rate.

TAPVD - See 'Total Anomalous Pulmonary Venous Drainage'.

Tetralogy - Used to describe a common heart defect with four components (Fallot's Tetralogy).

Thrill - A medical term used to describe the sensation which can be felt with the hand when it is placed on the chest wall in a patient with a very loud murmur, which is associated with vibrations of sufficient intensity for them to be felt at the surface of the chest.

Total Anomalous Pulmonary Venous Drainage (TAPVD)  - A defect in which the pulmonary (lung) veins are connected to veins from the body (i.e. the SVC or IVC) or to the right atrium, instead of returning to the left atrium).

Transposition  - This is a term used to mean that two structures (usually the aorta and pulmonary artery) are in the opposite position to normal such as in 'Transposition of the Great Arteries' (TGA). See also 'Congenitally Corrected Transposition Of The Great Arteries'.

Tricuspid Atresia  -  Complete obstruction to the tricuspid valve.

Tricuspid Stenosis - Narrowing of the tricuspid valve, resulting from a congenital defect of the valve leaflets or disease of the valve.

Tricuspid Valve - The valve at the junction of the right atrium with the right ventricle, which controls flow of blood into the ventricle before each contraction, and prevents backflow.

Truncus Arteriosus- A condition in which the aorta and main pulmonary artery are joined where they leave the heart. Blood from both ventricles passes across a VSD into this single arterial trunk.

Valve - A structure in a blood vessel or the heart which ensures blood flows only one way. They are constructed of single or multiple flaps which swing open to allow blood to flow forwards and swing shut to prevent back flow. The valve flaps are referred to as 'leaflets' or 'cusps'.

Veins - Blood vessels which carry blood back towards the heart, after it has circulated around the body. Veins usually carry deoxygenated blood, except in the pulmonary veins where oxygenated blood is carried back to the heart from the lungs.

Ventilate - To use a ventilator (respirator) to help a patient who cannot breath adequately for themselves.

Ventilator - See 'Respirator'.

Ventricle - One of the two powerful muscular chambers at the bottom of the heart which pump blood out to the body with each heart contraction.

Ventricular Septal Defect (VSD) - A defect (hole) in the ventricular septum which allows blood to shunt from one ventricle to the other.

Ventricular Septum - The septum (partition or wall) between the two ventricles.

VSD - See 'Ventricular Septal Defect'.

Xray - An Xray of the chest will often be performed as part of an initial assessment or a follow up appointment. This will show the size and shape of the heart and also helps to demonstrate effects of heart problems on the lungs (e.g. congestion of the lungs). Enlargement of the heart and abnormalities of its shape may give valuable information about many heart defects and their severity.

Acknowledgement:

Much of the information on this page is included in the Heartkids Booklet and is reproduced here with permission of Heartkids.