The Heart


As we work with children who have holes in their heart, our community takes an active interest in pediatric cardiology. On the bookshelf in our office is a concise guide to the science of the issue, created by our volunteer Ellen, a nursing student; we thought it would be helpful to have it sitting on our virtual shelf as well.

Catalogue of Heart Defects

  1. Aortic Stenosis (AS)/Aortic Valvular Stenosis (AVS) 
  2. Atrial Septal Defect (ASD)
  3. Artrioventricular Septal Defect (or AV Canal Defect) 
  4. Coartication of the Aorta
  5. Ebstein’s Anomaly
  6. Hypoplastic Left Heart Syndrome (HLHS)
  7. Interrupted Aortic Arch/Ventricular Septal Defect
  8. Patent Ductus Arteriosus
  9. Pulmonary Stenosis (PS)/Pulmonary Valvular Stenosis (PVS)
  10. Pulmonary Atresia (PA)
  11. Single Ventricle Anomalies
  12. Tetralogy of Fallot
  13. Total Anomalous Pulmonary Venous Return (TAPVR)
  14. Transposition of the Great Arteries (TGA)
  15. Tricuspid Atresia (TA)
  16. Truncus Arteriosus
  17. Vascular Rings
  18. Ventricular Septal Defect (VSD)
  19. Rare: Univentricular Heart

Cardiology 101

Before addressing the defects found in cardiology, one must first understand how a healthy heart functions.

The heart is a pump that constantly supplies the body with oxygen and nutrients via the blood supply. There are four chambers of the heart: a right atrium, a right ventricle, a left atrium and a left ventricle.

First, deoxygenated blood (blood without oxygen) is carried from the body through the Inferior and Superior Vena Cava. From these vessels, the blood is dumped into the Right Atrium of the heart. The atria serve as preliminary holding chambers; i.e. the main pumping chambers are the ventricles, and the atria hold the blood on standby before pumping it into the ventricles. Anyway, blood from the Right Atrium goes into the Right Ventricle from which the blood is pumped to the lungs via the Pulmonary Artery to get oxygenated (i.e. to get oxygen). Once oxygenated at the lungs, the blood returns to the heart via the Pulmonary Veins, and is dumped into the Left Atrium. From there, the blood is pumped into the Left Ventricle, and then is sent out to the body via a blood vessel called the Aorta. The blood travels throughout the body, oxygenating and nourishing the tissues, and then returns to the heart where the cycle starts all over again.

Defects can occur in any of the above structures or tissues.

In addition to the mechanisms and structures mentioned above, there are four major valves in the heart. These valves separate structures that need to allow the gradual, not sudden, passage of blood. Hence, the valves allow a measured amount of blood to pass through to these structures. The Tricuspid Valve separates the Right Atrium from the Right Ventricle, the Pulmonary Valve separates the Right Ventricle from the Pulmonary Artery, the Mitral Valve separates the Pulmonary Veins from the Left Atrium, and the Aortic Valve separates the Left Ventricle from the Aorta. Defects involving these valves are common; the valves can be too narrow, broken, or completely absent.

Lastly, an important aspect of pediatric cardiology involves fetal cardiology, which is the way the heart functions in utero. In utero, the child’s heart has two structures that disappear at birth: the Foramen Ovale and the Ductus Arteriosus. Since the child cannot breathe yet on its own without access to air, oxygen is supplied by the mother via the placenta. These structures allow blood to bypass the lungs. More specifically, the Foramen Ovale is a hole between the Right and Left Atria that allows blood to bypass the right side of the heart (where it would be sent to the lungs) and sends it directly to the left side of the heart. The Ductus Arteriosus is a structure connecting the Pulmonary Artery to the Aorta. Again, this shunts blood away from the lungs, and out to the body. Both of these holes should snap shut and should be fully sealed within 24 hours after birth; complications arise if they remain open. The patency of these structures qualifies as a cardiac defect.

 
 

Cardiac defects can occur in any of the above mentioned structures, involving broken, ineffective, or missing cardiac structures. These will be explained in detail in the following pages, and you may also consult the glossary for definitions of cardiac vocabulary.

 
Defects
 
1. Aortic Stenosis (AS)/Aortic Valvular Stenosis (AVS)

Aortic Stenosis (also called AS) refers to a condition in which there is a blockage preventing blood from traveling through the Left Ventricle to the Aorta. The blockage can be caused by a variety of reasons, including muscular obstructions below the valve, a narrowing of the aorta immediately after the valve, or, most often, the aortic valve itself is the cause. This condition is known as Aortic Valvular Stenosis (AVS).

The aortic valve is composed of three cusps (or leaflets) that open and shut as the heart pumps; if these leaflets do not open and close properly, a blockage may occur. As a result of the additional workload, the left ventricle will often hypertrophy (thicken) in order to provide the additional strength to eject the blood. Treatment depends on the severity of the defect. See illustration below.

 

 
2. Atrial Septal Defect (ASD)

There are two atria in the heart; one on the right and one on the left. The right atrium carries deoxygenated blood and the left atrium carries oxygenated blood. An ASD is when there is a hole between these two atria, resulting in a mixing of oxygenated and deoxygenated blood. See illustration below.

 
 

As you can see, more blood flows from left-to-right than right-to-left. This is because the pressure gradient is higher on the left side because it pumps blood to the entire body. As a result, more blood flows to the lungs than is normal, and respiratory conditions such as pulmonary hypertension (high blood pressure in the lungs) may emerge. Surgery for this procedure usually has no complications, and normal activity may be resumed following a successful surgery.

 
3. Atrioventricular Septal Defect (or AV Canal Defect) 

This defect is common in children with Down’s Syndrome. An Atrioventricular Septal Defect is when certain cardiac structures (known as endocardial cushions) fail to develop in utero. These structures divide the heart into four chambers, and without them, there is a tremendous amount of oxygenated and deoxygenated blood cross-over. See illustration below.

With this defect, a child may have absent tissue between the atria, the ventricles, or both. The range of severity of this defect merits a range of treatment.

 
4. Coarctation of the Aorta
Coarctation of the Aorta is the narrowing of the descending aorta . Some have speculated that this defect is caused by scar tissue narrowing the aorta during the closing of the ductus arteriosus. Blood flow to the lower extremities is therefore reduced, and children with this defect will often exhibit high blood pressure in the upper extremities (arms), and low blood pressure in the lower extremities (legs). See illustration below.
 
 
5. Ebstein's Anomaly
 
Ebstein’s Anomaly is a defect in the tricuspid valve of the heart, which separates the right atrium from the right ventricle. Because the three leaflets of the valve are deformed, they do not effectively seal the atrium from the ventricle. As a result, blood leaks backwards into the atrium rather than being pumped through the ventricle. The right atrium becomes enlarged, and, in severe cases, congestive heart failure may follow. Due to the increased pressure in the atrium, at birth the Patent Foramen Ovale (PFO) often remains open, leading to an Atrial Septal Defect. (The Foramen Ovale is a fetal circulatory structure which shunts blood from the right atrium to the left atrium in utero because oxygenated blood is provided by the placenta). See illustration below.
 
 
6. Hypoplastic Left Heart Syndrome (HLHS)

The Hypoplastic Left Heart Syndrome is one of the most complex heart defects. Essentially, the left ventricle is so underdeveloped that it might as well be completely missing. Due to the complexity, other anomalies occur as well, including a small aorta, a small aortic arch, a large Patent Ductus Arteriosus (PDA), and an Atrial Septal Defect (ASD). All of these additional anomalies are a result of the cardiac mechanics attempting to regulate the hypoplastic left ventricle. See illustration below. 

 

 

In such severe defects, transplants may be utilized. However, due to the scarcity of newborn organs and the chance of transplant rejection, surgeries have been developed to correct this problem. The treatment for this defect is usually completed with three surgeries; the Norwood, the Glenn and the Fontan procedures done at 1 week, 3-6 months, and 2-3 years respectively. These surgeries essentially work with the defect and ultimately make a workable pumping mechanism and eventually use the right ventricle as the primary chamber for pumping blood to the body.

 
7. Interrupted Aortic Arch/Ventricular Septic Defect

This defect is almost always accompanied with a Ventricular Septal Defect (VSD), and refers to an absence or discontinuation of the descending aorta. The aorta is the major vessel that takes the blood from the left ventricle, carrying it to the rest of the body. When this vessel is interrupted, the body compensates by shunting blood from the left ventricle through a hole due to VSD into the right ventricle, then up through the Patent Ductus Arteriosus (PDA; a hole between the aorta and the pulmonary artery that should close at birth) into the descending aorta. See illustration below. 

 

 
8. Patent Ductus Arteriosus (PDA)

In utero, the child has a structure known as the Ductus Arteriosus. This structure shunts blood away from the lungs into the aorta.  The lungs are not used in utero because oxygen is supplied by the mother via the placenta, as the child does not yet breathe independently. At birth, with the first cry, this structure snaps shut and should be completely sealed within the first 24 hours of life. However, when this fails to happen, the connection remains open throughout one’s life and is called a PDA. See illustration below.  

 

PDA causes blood in the aorta, fully oxygenated and ready to provide the rest of the body with oxygen, to be shunted back down to the pulmonary artery, creating a highly ineffective pumping system. Blood saturated with oxygen being repeatedly cycled through the lungs by the pulmonary artery means that less blood is sent out to the body. The child often has an enlarged heart due to the high volume of blood traffic, as well as a high blood volume in the lungs.

 
9. Pulmonary Stenosis (PS)/ Pulmonary Valvular Stenosis (PVS)

This defect involves the pulmonary artery. The pulmonary valve separating the right atrium from the pulmonary artery should be flexible, to allow for smooth blood flow. However, in this defect, a stenosis (narrowing) has occurred at or around the pulmonary valve, consequently inhibiting the flow of blood to the lungs for oxygenation. See illustration below.

 

This narrowing can occur at the valve, or immediately after. If the narrowing is at the valve, the defect is called Pulmonary Valvular Stenosis (PVS); if the defect is in the vessel, then it is simply called Pulmonary Stenosis (PS). 

 
10. Pulmonary Atresia (PA)

Pulmonary Atresia is when the pulmonary valve fails to develop an opening, resulting in a blockage between the right ventricle and the pulmonary artery, preventing blood from getting to the lungs. Several complications accompany this defect, including a smaller right ventricle (as it is not in strenuous use) and both the Ductus Arteriosus and Foramen Ovale (remnants of the fetal circulatory system) remain patent (open) in order to bypass the pulmonary valve and provide a compensatory passage for blood flow.

Rather than following its intended course, the blood travels through the Patent Foramen Ovale (PFO) into the left atrium, from which the blood goes up the aorta with some of the blood going through the Patent Ductus Arteriosus (PDA) down to the lungs, while the rest of the blood continues to the body. See illustration below.

 
11. Single Ventricle Anomalies

Single Ventricle Anomalies is a term applied to several different defects; the name simply means that one of the two ventricles is underdeveloped to the point that it is unable to function adequately. Defects in this category are numerous, including disorders such as Tricuspid Atresia and Hypoplastic Left Heart Syndrome.

 
12. Tetralogy of Fallot

Tetralogy of Fallot is a complex heart defect involving a combination of four specific defects (tetra=four), including pulmonary stenosis, Ventricular Septal Defect (VSD), overriding aorta, and right ventricle hypertrophy. Pulmonary Stenosis is when there is a narrowing of the pulmonary artery, which decreases blood flow. Secondly, a VSD, the most common pediatric heart defect, is a hole between the right and left ventricles of the heart (discussed in detail on page 18). Thirdly, an overriding aorta simply means that the aorta (the vessel that carries blood from the heart to the body) appears to stem from both the right and the left ventricles instead of just the left, as in a normal heart. This causes a mixing of oxygenated and deoxygenated blood, and the child will often exhibit a cyanotic (blue) color. Lastly, right ventricular hypertrophy is when the right ventricle is overly muscular and large in size, compensating for an increased workload. Due to the complexity of the defect, the child can also exhibit additional defects, such as an ASD, poor placement of the coronary arteries, etc. Surgery is always needed to correct this problem.

 
 
13. Total Anomalous Pulmonary Venous Return (TAPVR)

This defect is a rare abnormality involving the placement of the pulmonary veins. Normally, the pulmonary veins take blood from the lungs and dump it into the left atrium to be sent out to the body. With this defect, however, the pulmonary veins drain back into the right atrium instead of the left. This means that all of the oxygenated blood returns to the right ventricle, mixing with the deoxygenated blood that has returned from the body, thus lowering the oxygen saturation of the blood. See illustration below.

 

 

In addition to the low oxygen saturation, the Foramen Ovale (a hole between the atria from the fetal circulatory system that should completely close within 24 hours of birth) remains open because of the pressure gradient caused by the TAPVR. The Foramen Ovale becomes an Atrial Septal Defect (ASD) that allows a way for the mixed blood from the right atria to travel to the left atria and ultimately to the left ventricle to at least partially oxygenate the rest of the body.

 
14. Transposition of the Great Arteries (TGA)

TGA is when the aorta and the pulmonary artery are switched; the pulmonary artery rises from the left ventricle and the aorta rises from the right ventricle, which is the opposite of what a normal heart should look like. This causes a massive problem as blood is going in the exact opposite area of the body where it is needed. See illustration below.

 

 

With this defect, the blood is trapped on either side of the heart; the blood on the right side mostly stays on the right side, cycling through the lungs and back to the right side, and the blood on the left side mostly stays on the left, cycling through the body and back to the left side. Consequently, the heart is not working in a functional manner and, ultimately, very little oxygenated blood escapes this ineffective cycle to nourish the body.

Like TAPVR, TGA also causes a structural defect to compensate for this anomaly. The first possibility is that the two fetal circulatory structures (the Foramen Ovale and the Ductus Arteriosus) may remain open in order to provide a passageway for blood to flow between the right and left sides of the heart. The second possibility is the presence of a Ventricle Septal Defect (VSD) or an Atrial Septal Defect (ASD). In either case, there is an abnormal structure allowing the passage of blood between the two sides of the heart. To correct this defect (or series of defects), major surgery is required.

 
15. Tricuspid Atresia

Tricuspid Atresia is where the tricuspid valve (the valve between the right atrium and the right ventricle) fails to develop normally. As a result, the right ventricle is seriously underdeveloped (qualifying this defect as a single ventricle anomaly, as discussed on page 12) and other structural abnormalities may be present as well, such as VSDs, ASDs, PDAs, and TGAs. See illustration below.

 

 

The implications of this defect are that a less than normal amount of blood goes to the lungs. Blood therefore, passes through the Foramen Ovale (a structure from fetal circulation), creating as ASD (Atrial Septal Defect) for the blood to pass over to the left side of the heart. Then either a VSD (Ventricular Septal Defect) or PDA (Patent Ductus Arteriosus) allows the passage of blood to the lungs. 

 
16. Truncus Arteriosus

Truncus Arteriosus is where a single artery emerging from the heart forms both the pulmonary artery and the aorta (in a normal heart these are two separate vessels). See illustration below. 

 

A Ventricular Septal Defect (VSD) is typically present as well. This second defect allows the mixed blood to pass through the single artery, and go to both the lungs and the body.

 
17. Vascular Rings

The term “Vascular Rings” applies to a number of defects, all of which involve a deformation of the aortic arch around the esophagus or the trachea. A variety of deformations can occur, but they all in some way restrict the trachea or esophagus. As you can imagine, such a defect not only affects the patient’s cardiovascular system, but the respiratory and gastrointestinal systems as well. In addition to signs of a cardiac defect, patients may also have symptoms of noisy breathing or difficulty swallowing.

 
18. Ventricular Septal Defect (VSD)

Ventricular Septal Defects are one of the most common pediatric cardiac defects. In normal cardiology, the right side of the heart receives deoxygenated blood from the body and takes the blood to the lungs to be re-oxygenated. The blood then goes to the left side of the heart where it is pumped out to the body. A VSD indicates that there is a hole between the right and left ventricles of the heart, causing the oxygenated and deoxygenated blood to mix. Because of different pressure gradients (the left side of the heart has a higher pressure than the right), blood is shunted from the left ventricle to the right. See illustration below. 

 

As a result, the heart becomes an ineffective pump, as oxygenated blood is sent to the lungs twice to be oxygenated. The size, location, and composition of the VSD dictate the severity.


 
19. Univentricular Heart
This is a very rare heart defect. The American Heart Association quotes its frequency as 54 cases per million, or .0054% of the population. 

The two ventricles of the heart are malformed into one super-ventricle, resulting in a dangerous and inefficient mixture of oxygenated and deoxygenated blood. Surgical correction usually requires two separate operations. The American Heart Association further says that the univentricular heart defect has "inspired some of the most creative surgical and interventional approaches in human history."

Glossary
 
A
Ablation
Elimination or removal. Also refers to a procedure that eliminates extra electrical pathways within the heart that cause fast or irregular heart rhythms.
ACE (Angiotensin-Converting Enzyme) Inhibitor
A medication that opens up blood vessels, making it easier for the heart to pump blood forward to the body; also used to lower blood pressure.
Acyanotic
Refers to a group of congenital heart defects in which there is a normal amount of oxygen in the bloodstream, giving a pink color to the lips and nailbeds.
Anastomosis
A surgical connection between two structures, often between two blood vessels.
Aneurysm
A thin, weakened area in a blood vessel or an area of the heart.
Angiography
An x-ray study that uses dye injected into the arteries to study blood circulation.
Angioplasty
A non-surgical procedure for treating narrowed arteries.
Anticoagulant
A medication that keeps blood from clotting.
Antihypertensive
A medication that lowers blood pressure.
Aorta
The largest artery in the body and the primary blood vessel that carries oxygenated blood out of the heart to the rest of the body.
Aortic Arch
The curved portion of the aorta (the large blood vessel that carries oxygen-rich blood away from the heart to the rest of the body).
Aortic Regurgitation
Backwards leakage of blood from the aorta into the left ventricle as a result of a weakened aortic valve, resulting in unhealthy stress in the left heart side of the heart and inadequate blood flow to the body.
Aortic Stenosis
A narrowing of the opening of the aortic valve (the valve that regulates blood flow from the left ventricle into the aorta).
Aortic Valve
The valve that regulates blood flow from the left ventricle of the heart into the aorta.
Arrhythmia (also called Dysrhythmia)
A fast, slow, or irregular heartbeat.
Arterioles
Small branches of arteries.
Artery
A blood vessel that carries oxygenated blood away from the heart to the rest of the body.
Arteriosclerosis
Commonly called the "hardening of the arteries," it is a variety of conditions due to fatty or calcium deposits in the artery walls, causing them to thicken.
Asplenia
Absence of the spleen, either from improper development before birth, or due to the surgical removal of the spleen resulting from injury or disease.
Atresia
Inadequate development of an organ or part of an organ during pregnancy.
Atrial Fibrillation
A very fast and irregular beating of the atria (the upper two chambers of the heart).
Atrial Flutter
A very fast beating of the atria (the upper two chambers of the heart).
Atrial Septal Defect (ASD)
A hole in the wall between the right and left atria (the two upper chambers of the heart).
Atrial Septum
The wall between the right and left atria (the two upper chambers of the heart).
Atrioventricular Canal
Refers to a congenital heart defect involving an opening low in the atrial septum, an opening high in the ventricular septum, and abnormal development of the mitral and/or tricuspid valves.
Atrium (plural: Atria)
One of two upper chambers in the heart.
Atrioventricular Block
An interruption of the electrical signal between the atria and the ventricles.
Atrioventricular (AV) Node
A cluster of cells between the atria and ventricles that regulate the electrical current.
 
B
Bacterial Endocarditis
A bacterial infection of the valves and interior surfaces of the heart.
Balloon Angioplasty
A procedure usually done in the cardiac catheterization laboratory that uses a catheter (tube) with a balloon in the tip to open up a narrowed valve or blood vessel.
Beta Blocker
A medication that limits the activity of epinephrine (a hormone that increases blood pressure).
Bicuspid
A valve that has two leaflets.
Biopsy
A procedure in which tissue samples are removed from the body for microscopic examination to establish a diagnosis.
Blood Clot
A thick, gelled mass of blood.
Blood Pressure
The force or pressure exerted by the heart when pumping blood; the pressure of blood in the arteries.
Blood Pressure Cuff
A device usually placed around the upper portion of the arm to measure blood pressure.
Brady
Suffix meaning "slow," used to form compound words.
Bradycardia
Abnormally slow heartbeat.
Bundle-Branch Block
A condition in which the heart's electrical system is unable to normally conduct the electrical signal.
 
C
Calcium Channel Blocker
A medication that lowers blood pressure.
Capillaries
Tiny blood vessels between arteries and veins that distribute oxygen-rich blood to the body.
Cardiac
Pertaining to the heart.
Cardiac Arrest
The stopping of the heartbeat.
Cardiac Catheterization
A diagnostic procedure in which a tiny, hollow tube (catheter) is inserted into an artery or vein in order to evaluate the heart and blood vessels.
Cardiac Output
The amount of blood that goes through the circulatory system in one minute.
Cardiologist
A physician who specializes in the medical evaluation and treatment of heart diseases.
Cardiology
The clinical study and practice of treating the heart.
Cardiomyopathy
A disease of the heart muscle that causes it to lose its pumping strength.
Cardiovascular (CV)
Pertaining to the heart and blood vessels (the circulatory system).
Cardioversion
The procedure of applying electrical shock to the chest to change an abnormal heartbeat into a normal one.
Carotid Artery
The major arteries in the neck that supply blood to the brain.
Catheter
A small, thin tube; may refer to a tube used during a cardiac catheterization procedure to inject dye, obtain blood samples, and measure pressures inside the heart; may also refer to a small tube used to help drain the bladder during and after a surgical procedure.
Cholesterol
A waxy substance that is produced by the human body. It is also found in animal fats, shellfish, and in dairy products (such as beef, chicken, pork, butter, milk, cheese, and eggs).
Cineangiography
The procedure of taking moving pictures to show the passage of dye through blood vessels.
Circulatory System
Pertaining to the heart and blood vessels, and the circulation of blood.
Closed Heart Surgery
An operation that repairs problems involving the blood vessels attached to the heart, and may not need the use of the heart-lung bypass machine.
Coarctation of the Aorta
A congenital heart defect that results in narrowing of the aorta.
Collateral Vessels
New blood vessels that are created by the body to provide extra blood flow to an area when the blood vessel(s) that are already there are too small, narrowed, or blocked.
Computerized Tomography Scan (Also called a CT or CAT scan)
A non-invasive procedure that takes cross-sectional images of the brain or other internal organs; to detect any abnormalities that may not show up on an ordinary x-ray.
Conduction System
The electrical system inside the heart that stimulates the heart to beat.
Congenital
Present at birth.
Congenital Heart Defect
A heart problem present at birth, caused by improper development of the heart during fetal development.
Congenital Heart Disease
See congenital heart defect.
Congestive Heart Failure
A condition in which the heart cannot pump out all of the blood that enters it, which leads to an accumulation of blood in the vessels leading to the heart and fluid in the body tissues. Excess blood in the pulmonary (lung) blood vessels can also occur, leading to fluid accumulation in the lungs.
Coronary Arteries
Two arteries that come from the aorta to provide blood to the heart muscle.
Cyanosis
Insufficient oxygen in the blood.
Cyanotic
Appearing blue, due to insufficient oxygen in the blood.
 
D
Defibrillator
An electronic device used to establish normal heartbeat.
Dextrocardia
A heart that is "flipped over," so that the structures that are normally on the right side of the chest are on the left, and vice versa. The arteries and veins are connected correctly; occurs due to an abnormality in heart development during pregnancy.
Diastole
The time during each heartbeat when the ventricles are at rest, filling with blood and not pumping.
Diastolic Blood Pressure
The lowest blood pressure measure in the arteries, which occurs between heartbeats.
DiGeorge Syndrome (also known as Shprintzen, Velo-Cardio-Facial, and 22q11.2 Deletion Syndrome)
A genetic disease caused by a missing piece of chromosome material on chromosome #22 that results in many different health problems, and affects the normal fetal development of the heart, thymus, and parathyroid glands.
Diuretic
A medication that helps the kidneys to remove excess fluids from the body, lowering blood pressure as well as decreasing edema (swelling).
Doppler Ultrasound
A procedure that uses sound waves to evaluate heart, blood vessels, and valves.
Double Outlet Right Ventricle
A congenital heart defect in which both the aorta and the pulmonary artery are connected to the right ventricle.
Down Syndrome (also called Trisomy 21)
A combination of birth defects caused by the presence of an extra #21 chromosome in each cell of the body. Many children with Down syndrome also have congenital heart disease - usually atrioventricular canal defect.
Ductus Arteriosus
A connection between the aorta and the pulmonary artery that is necessary in fetal life, but becomes unnecessary after birth.
Dyspnea
Shortness of breath.
Dysrhythmia
An abnormal heart rhythm.
 
E
Ebstein's Anomaly
Abnormal development of the tricuspid valve during pregnancy, causing an abnormally positioned valve that does not open easily (stenosis) and allows backflow of blood from the right ventricle into the right atrium (regurgitation).
Echocardiogram (echo)
A procedure that evaluates the structure and function of the heart by using sound waves recorded on an electronic sensor which produce a moving picture of the heart and heart valves.
Edema
Swelling.
Effusion
A collection of fluid in a closed cavity.
Ejection fraction
The measurement of the amount of blood pumped out of the ventricles.
Electrocardiogram (ECG or EKG)
A test that records the electrical activity of the heart, shows abnormal rhythms (arrhythmias or dysrhythmias), and detects heart muscle stress.
Electrophysiological Study (EPS)
A cardiac catheterization to study electrical current in patients who have arrhythmias.
Endocardium
The membrane that covers the inside surface of the heart.
Endocarditis
A bacterial infection of the valves and interior surfaces of the heart.
End-to-End Anastomosis
Aurgical connection of two segments of blood vessel by stitching the open end of one segment to the open end of another segment.
Enlarged Heart
A condition of the heart in which it is larger than normal.
Epicardium
The membrane that covers the outside of the heart.
Exercise Electrocardiogram (ECG or EKG)
A test to assess the cardiac rhythm and function by having the child exercise on a treadmill or bicycle.
 
F
Failure to Thrive
Failure to grow and gain weight; often due to increased energy expenditure with congenital heart disease.
Fibrillation
Rapid contractions of the heart muscles.
Fluoroscopy
An x-ray procedure that takes continuous pictures to evaluate moving structures within the body, such as the heart.
Flutter
Ineffective contractions of the heart muscles.
Fontan Procedure
A surgical procedure performed to repair heart defects in which only one ventricle is functional. It connects the right atrium to the pulmonary artery, allowing oxygen-poor (blue) blood from the body to flow into the lungs.
Foramen Ovale
A hole between the right and left atria, present in all unborn children, that remains open after birth for variable periods of time.
 
G
Glenn Shunt
A surgical connection between the superior vena cava and the right pulmonary artery, allowing oxygen-poor (blue) blood to flow into the lungs.
 
H
Heart Attack (also called Myocardial Infarction)
Occurs when one of more regions of the heart muscle experience a severe or prolonged decrease in oxygen supply caused by a blocked blood flow to the heart muscle.
Heart Block
Interrupted electrical impulse to heart muscles.
Heart-Lung Bypass Machine
A machine that performs for the heart and lungs during open heart surgery.
Heart Valve Prolapse
A condition of the heart valve in which it is partially open when it should be closed.
High Blood Pressure (also called Hypertension)
Blood pressure that is above the normal range.
High Density Lipoprotein (HDL)
The "good" cholesterol that promotes breakdown and removal of cholesterol from the body.
Holter Monitor
A portable EKG machine worn for a 24-hour period or longer to evaluate irregular, fast, or slow heart rhythms while engaging in normal activities.
Homograft
A blood vessel taken from a tissue donor, used to replace a defective blood vessel, most often the pulmonary artery or aorta.
Hypertrophic obstructive cardiomyopathy (Also called HOCM, hypertrophic cardiomyopathy, asymmetrical septal hypertrophy, or ASH, or idiopathic hypertrophic subaortic stenosis or IHSS)
Enlarged heart muscle that causes impeded blood flow.
Hypoplastic
Refers to an abnormally small organ or blood vessel due to abnormal development prior to birth.
Hypoplastic Left Heart Syndrome
A congenital heart defect in which the left side of the heart is poorly developed, resulting in small mitral valve, left ventricle, and aorta.
Hypotension
Low blood pressure.
Hypoxia
Abnormal oxygen content in the organs and tissues of the body.
 
I
Immunosuppressive Medications
Medications that suppress the body's immune system; used to minimize rejection of transplanted organs.
Incision
A cut made with a surgical instrument during an operation.
Inferior Vena Cava
The large blood vessel (vein) that returns blood from the legs and abdomen to the heart.
Insufficiency
A valve deformity that allows the blood to leak backwards when the valve is closed.
Ischemia
Decreased flow of oxygenated blood to an organ due to obstruction in an artery.
Ischemic Heart Disease
Coronary artery disease or coronary heart disease caused by narrowing of the coronary arteries and decreased blood flow to the heart.
 
J
Jugular Veins
Veins that carry blood from the head back to the heart.
 
K
Kawasaki Disease
An immune system disorder affecting the heart, particularly the coronary arteries.
 
L
Left Atrium
The upper left-hand chamber of the heart. It receives oxygen-rich (red) blood from the lungs via the four pulmonary veins, and then sends this blood to the left ventricle.
Left Ventricle
The lower left-hand chamber of the heart. It receives oxygen-rich (red) blood from the left atrium and pumps it into the aorta, which takes the blood to the body. The left ventricle must be strong and muscular in order to pump enough blood to the body to meet its requirements.
Lesion
An injury or wound.
Lipid
A fatty substance in the blood.
Lipoproteins
Transporters of fatty substances in the blood.
Low Density Lipoprotein (LDL)
The primary cholesterol-carrying substance in the body. In large amounts, it accumulates inside arteries.
Lumen
The hollow area inside a blood vessel.
 
M
Magnetic Resonance Imaging (MRI)
A diagnostic procedure that uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body.
Marfan Syndrome
A genetic disorder which affects the connective tissue of the body. It causes dilation of blood vessels and abnormalities of cardiac valves.
Mechanical Valve
An artificial valve used to replace a diseased or defective valve, most often the aortic valve.
Median Sternotomy
An incision in the center of the chest, from the top to the bottom of the breastbone, used for many congenital heart defect repair surgeries.
Mitral Valve
The valve that controls blood flow between the left atrium and left ventricle in the heart.
Mitral Valve Prolapse
An abnormality of the valve between the left atrium and left ventricle of the heart that causes backward flow of blood from the left ventricle into the left atrium.
Monounsaturated Fats
Dietary fats, such as olive oil or canola oil, that may lower LDL cholesterol levels.
Murmur
A blowing or rasping sound heard while listening to the heart that may or may not indicate problems within the heart or circulatory system.
Myocardial Infarction (also called Heart Attack)
Occurs when one of more regions of the heart muscle experience a severe or prolonged decrease in oxygen supply caused by a blocked blood flow to the heart muscle.
Myocardial Ischemia
Insufficient blood flow to part of the heart.
Myocarditis
Inflammation of the heart muscles.
Myocardium
The muscular layer of the heart.
 
N
Noninvasive Procedure
A diagnostic effort or treatment that does not require entering the body or puncturing the skin.
 
O
Obesity
Overweight by 30 percent of the ideal body weight.
Occluded Artery
An artery that is narrowed by plaque that impedes blood flow.
Open Heart Surgery
Surgery that involves opening the chest and heart while a heart-lung machine performs for the heart and lungs during the operation.
Oxygen Desaturation
Insufficient amounts of oxygen in the bloodstream. Desaturation can occur when oxygen-poor (blue) blood from the right side of the heart circulation mixes with oxygen-rich (red) blood in the left side of the heart circulation and goes to the body. Normal oxygen saturation in the arteries is 95 to 100 percent.
Oxygen Saturation
The extent to which the hemoglobin is saturated with oxygen. (Hemoglobin is an element in the bloodstream that binds with oxygen and carries it to the organs and tissues of the body.) A normal oxygen saturation of the blood leaving the heart to the body is 95 to 100 percent. The oxygen saturation of the blood returning to the heart after delivering oxygen to the body is 75 percent.
 
P
Pacemaker
An electronic device that is surgically placed in the patient's body and connected to the heart to regulate the heartbeat.
Palpitation
A sensation in the chest caused by an irregular heartbeat.
Patent
Open.
Patent Ductus Arteriosus (PDA)
A blood vessel present in all infants that usually closes shortly after birth. It connects the aorta to the pulmonary artery. When it remains open, it allows extra blood to pass through from the aorta to the lungs.
Patent Foramen Ovale
An opening in the atrial septum (wall between the right and left atria) that is present in all infants, but which usually closes shortly after birth. When it remains open, it allows extra blood to pass through the opening from the left atrium to the right atrium.
Pericardial Effusion
A build up of excess fluid in-between the heart and the membrane that surrounds it, often due to inflammation.
Pericarditis
An inflammation or infection of the sac which surrounds the heart.
Pericardiocentesis
A diagnostic procedure that uses a needle to draw fluid from the pericardium.
Pericardium
The membrane that surrounds the heart.
Plaque
Deposits of fat or other substances attached to the artery wall.
Platelets
Cells found in the blood that assist in clotting.
Polyunsaturated Fat
A type of fat found in vegetable oils and margarines that does not appear to raise blood cholesterol levels.
Post-Pericardiotomy Syndrome
A build up of excess fluid in-between the heart and the membrane that surrounds it, often due to inflammation after open heart surgery. ("Post" means after, and "pericardiotomy" means opening the membrane around the heart for open heart surgery.)
Premature Atrial Contraction (PAC)
An early heartbeat started by the atria.
Premature Ventricular Contraction (PVC)
An early heartbeat started by the ventricles.
Prophylaxis
Prevention.
Prostaglandin E1
An intravenous medication used to keep a patent ductus arteriosus from closing and preserve blood flow to the lungs.
Pulmonary
Pertaining to the lungs and respiratory system.
Pulmonary Artery
The blood vessel connecting the right ventricle to the lungs, allowing oxygen-poor (blue) blood to receive oxygen.
Pulmonary Edema
A condition in which there is fluid accumulation in the lungs caused by an incorrectly functioning heart.
Pulmonary Valve
The heart valve located between the right ventricle and the pulmonary artery that controls blood flow to the lungs.
Pulmonary Vein
The vessel that carries oxygenated blood from the lungs to the left side of the heart.
Pulse Oximeter
A device that measures the amount of oxygen in the blood. Normal oxygen saturation in the arteries is 95 to 100 percent.
 
Q
R
Radioisotope
A radioactive material injected into the body so that a nuclear scanner can make pictures.
Regurgitation
Backward flow of blood caused by a defective heart valve.
Renal
Pertaining to the kidneys.
Rheumatic Fever
A disease caused by a strep infection that may damage the heart valves.
Right Atrium
The upper right chamber of the heart, which receives oxygen-poor (blue) blood from the body and sends it to the right ventricle.
Right Ventricle
The lower right chamber of the heart, which receives oxygen-poor (blue) blood from the right atrium and sends it to the pulmonary artery.
Risk Factor
A condition, element, or activity that may adversely affect the heart.
Ross Procedure
A surgical procedure performed to repair aortic stenosis. The child's own pulmonary valve and base of the pulmonary artery (autograft) replace the defective aorta, while a homograft (blood vessel from a tissue donor) replaces the pulmonary valve and base of the pulmonary artery.
Rubella
An illness that can cause birth defects, including congenital heart disease, if a woman contracts it for the first time during pregnancy; can be prevented by immunization with the MMR vaccine.
 
S
Saturated Fat
Fat that is found in foods from animal meats and skin, dairy products, and some vegetables. Saturated fats are usually solid at room temperatures and can increase LDL levels.
Septal Defect
A hole in the wall between the atria or the ventricles (upper or lower heart chambers).
Septum
The muscle wall between the atria or ventricles (upper or lower heart chambers).
Shunt
A connector to allow blood flow between two locations.
Sinus Node
The cells that produce the electrical impulses that cause the heart to contract.
Sinus Rhythm
A normal heart rhythm in which each heartbeat originates in the sinus node, and proceeds through the rest of the electrical conduction system normally.
Sinus Tachycardia
A heart rhythm that originates in the sinus node and proceeds through the rest of the electrical conduction system, but is faster than normal.
Sphygmomanometer
An instrument used to measure blood pressure.
Stent
A device implanted in a vessel used to help keep it open.
Stenosis
Narrowing or constriction of a blood vessel or valve in the heart.
Stethoscope
An instrument used to listen to the heart and other sounds in the body.
Sternotomy
A surgical incision made in the breastbone.
Sternum
The breastbone.
Stress
Mental or physical tension that results from physical, emotional, or chemical causes.
Stroke
The sudden disruption of blood flow to the brain.
Subclavian
A blood vessel that branches from the aorta and takes oxygen-rich (red) blood to the head and arms.
Subclavian Flap
A surgical procedure performed to repair coarctation of the aorta, using part of the left subclavian artery as a patch to enlarge a narrowed aorta.
Superior Vena Cava
The large vein that returns blood to the heart from the head and arms.
Supraventricular Tachycardia
A fast heart rate that originates in the aorta, but does not start in the sinus node.
Syncope
Light-headedness or fainting caused by insufficient blood supply to the brain.
Systole
The time during the heartbeat when the ventricles are pumping blood, either to the lungs or to the body.
Systolic Blood Pressure
The highest blood pressure measured in the arteries.
 
T
Tachycardia
Rapid heartbeat.
Tachypnea
Rapid breathing.
Tamponade
An emergency situation that occurs when blood or fluid fills the pericardial sac surrounding the heart, preventing the heart from beating effectively.
Telemetry Unit
A small box with wires attached to EKG patches on the chest; used to send information about the heartbeat via radio transmission to healthcare professionals for evaluation.
Tetralogy of Fallot (TOF)
A group of congenital heart defects, including a ventricular septal defect, obstruction to blood flow out of the right ventricle to the lungs, and an aorta that is shifted to the right. Enlargement of the right ventricle occurs as the right ventricle copes with obstruction to blood flow.
Thoracotomy
An incision made on the right or left side of the chest between the ribs, in order to access the heart or lungs during surgery.
Trans Fat
Vegetable oil that has been treated with hydrogen in order to make it more solid and give it a longer shelf life.
Transesophageal Echocardiography (TEE)
A diagnostic test that uses a long tube guided into the mouth, throat, and esophagus to evaluate the structures inside the heart with sound waves.
Transplantation
Replacing a damaged organ with one from a donor.
Transposition of the Great Arteries (also called Transposition of the Great Vessels)
A congenital heart defect involving abnormal development of the great arteries (the aorta and the pulmonary artery) during the time the heart is forming prior to birth. The aorta ends up being connected to the right ventricle, and the pulmonary artery is connected to the left ventricle, which is the opposite of how they are normally connected.
Tricuspid Atresia
A congenital heart defect in which the tricuspid valve and right ventricle do not develop properly, preventing oxygen-poor (blue) blood from reaching the lungs via its normal pathway.
Tricuspid Valve
The heart valve that controls blood flow from the right atrium into the right ventricle.
Triglyceride
A fat-like substance found in the blood.
Trisomy 21 (also called Down syndrome)
The presence of three #21 chromosomes in each cell of the body, rather than the usual pair, which causes the features otherwise known as Down syndrome. Many children with Down syndrome also have congenital heart disease - usually atrioventricular canal defect.
Truncus Arteriosus
A congenital heart defect involving incomplete separation of the great arteries (the aorta and the pulmonary artery) during the time the heart is forming prior to birth.
 
U
Ultrasound
A diagnostic tool used to evaluate organs and structures inside the body with high-frequency sound waves.
 
V
Valves
The "doors" between the chambers of the heart that allow blood to move forward and prevent it from moving backward. The heart valves are called tricuspid, pulmonic, mitral, and aortic.
Valvuloplasty
Repairing a heart valve.
Vascular
Pertaining to blood vessels.
Vasodilator
A medication that dilates or widens the opening in a blood vessel.
Vasopressor
A medication that raises blood pressure.
Vasovagal Syndrome
A sudden drop in blood pressure, with or without a decrease in heart rate, that is caused by a dysfunction of the nerves controlling the heart and blood vessels.
Vein
A blood vessel that carries blood from the body back into the heart.
Ventricle
One of the two lower chambers of the heart.
Ventricular Fibrillation
A condition in which the ventricles contract in rapid and unsynchronized rhythms and cannot pump blood into the body.
Ventricular Septal Defect
An abnormal opening in the wall between the right and left ventricles.
Ventricular Tachycardia
A condition in which the ventricles beat very quickly.
Vertigo
Dizziness.
 
W
Wolff-Parkinson-White syndrome
An extra electrical pathway that connects the atria and ventricles and causes rapid heartbeat.
 
X
X-ray
A diagnostic test which uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film.
 
Y
 
Z
 
Glossary used with permission and obtained from the Heart Institute Encyclopedia of the Cincinnati Children’s Hospital Medical Center at http://www.cincinnatichildrens.org/health/heart-encyclopedia/glossary.htm 28 July 2010.