Congenital Heart Defects (CHD)

Congenital heart defects (CHD) refer to heart defects that are present at birth. One or more heart structures or those structures connected to the heart develop abnormally before birth.

 

These defects happen when the blood vessels near the heart or the heart itself don’t develop normally before birth. This type of heart defect is the most common type of birth defect that children may be born with.

 

It is crucial to work with your child’s pediatrician and/or pediatric cardiologist to diagnose and treat your child’s heart defect in a timely manner.

 

Here is a video that gives a quick overview of CHD: View here

 

( video courtesy CDC)

COMMON TYPES OF HEART DEFECTS

 

There are more than 35 different types of congenital heart defects. Most of them affect the walls of the heart, the heart valves or the blood vessels connected to the heart. Some of these defects can be deadly if they are not treated promptly. So timely diagnosis and treatment are required.

 

We are going to discuss 14 of the most common heart defects diagnosed in children.

*Please review the Anatomy of the Heart summarized in the Human Heart section to assist in understanding the heart structure and how blood travels through the heart and out to the body. This summary will help you better understand some of the terms included below.

Ventricular Septal Defect (VSD)

A ventricular septal defect (VSD) is a hole or opening in the septum or wall between the two lower heart chambers (the right ventricle and left ventricle). Typically, the blood pressure in the left ventricle is about 3-4 times higher than the blood pressure in the right ventricle. With this open communication between the two ventricles, the blood flows from the left ventricle (area of high pressure) to the right ventricle (area of low pressure).

A large VSD will allow for more blood flow than a small VSD. Long term, if the VSD is not repaired, the added blood flow increases the pressure in the blood vessels of the lungs. This condition is called pulmonary hypertension (abnormally high blood pressure in the lungs).

The added flow and abnormally high pressure in the lungs can cause the heart to work harder. Over time, congestive heart failure develops. Signs of congestive heart failure can include fast breathing, sweating when feeding, and poor weight gain.

The linked KHAN ACADEMY® video lecture explains VSD in an easy to understand way: View here

Coarctation of the Aorta

The aorta is the large blood vessel that sends oxygen-rich blood from the left ventricle to the body. Blood vessels called arteries branch off the aorta in various locations, delivering blood to different parts of the body.

Coarctation of the aorta is abnormal narrowing of the aorta. The narrowing of the aorta commonly occurs just after the area where the arteries delivering blood to the head and upper body are located. The blood pressure measured on the right arm is higher than the blood pressure measured on the left arm or either leg.

The coarctation or narrowing of the aorta causes the blood pressure to increase back to the left ventricle. If the coarctation is severe, the left ventricle has to work harder to pump against this increased pressure. Over time, the left ventricle can fail. The child may display symptoms of fast breathing, increased work of breathing, sweating, poor feeding and poor weight gain.

The linked KHAN ACADEMY® video lecture explains the Eisenmenger Coarctation of the aorta in an easy to understand way: View here

Patent Ductus Arteriosus (PDA)

The ductus arteriosus is a blood vessel that connects the main pulmonary artery (blood vessel from the right ventricle to the blood vessels in the lungs) to the aorta (blood vessel from the left ventricle to the body). In utero, the fetus receives oxygen-rich blood from the mother, so the blood does not need to travel through the lungs of the fetus. After the blood travels through the right atrium and right ventricle, the blood goes out to the main pulmonary artery and travels through to the aorta. The blood bypasses the lungs because of the high pressure in the lungs.

When the baby takes his/her first breaths, the high pressure in the lungs drops. When this happens, the oxygen-poor blood travels from the right ventricle through the main pulmonary artery and into the lungs. The ductus arteriosus normally closes within hours or days after birth.

Sometimes the ductus arteriosus remains open after birth, usually in premature infants. If it remains open (fully or partially), the blood will flow from the aorta (area of high pressure) to the pulmonary artery (area of low pressure). This extra blood flow increases the pressure in the blood vessels of the lungs. This condition is called pulmonary hypertension (abnormally high blood pressure in the lungs).

The added flow and abnormally high pressure in the lungs can cause the heart to work harder. Over time, congestive heart failure develops. Signs of congestive heart failure can include fast breathing, sweating when feeding, and poor weight gain.

The linked KHAN ACADEMY® video lecture explains PDA in an easy to understand way: View here

Atrial Septal Defect (ASD), Ostium Secundum

An atrial septal defect is a hole in the wall between the upper heart chambers (right atrium and left atrium). There are 4 types of ASDs defined by the location of the defect. An ostium secundum ASD is the most common type of ASD. It is usually located in the center of the septum (wall between the right atrium and left atrium). The blood pressure in the left atrium is normally higher than the blood pressure in the right atrium. With this open communication between the two chambers, the blood flows from the left atrium to the right atrium.

A large ASD will allow for more blood flow than a small ASD. Over time, the extra blood flow can cause the right atrium and right ventricle to become dilated. In some cases, if the defect is left untreated, this extra blood flow traveling from the right ventricle to the lungs increases the pressure in the blood vessels of the lungs. This condition is called pulmonary hypertension (abnormally high blood pressure in the lungs).

The added flow and abnormally high pressure in the lungs can cause the heart to work harder. Over time, congestive heart failure develops. Signs of congestive heart failure can include fast breathing, sweating when feeding, and poor weight gain.

A small ASD will allow for limited blood flow across the defect, having little to no negative effects on the size and function of the right atrium and right ventricle. Thus, the child may not show any symptoms.

Atrioventricular Septal Defect (AVSD)

Other names of AVSD can include endocardial cushion defect or common atrioventricular canal defect.

An atrioventricular septal defect involves the walls between the upper chambers (atrial septum) and lower chambers (ventricular septum) of the heart as well as the valves between upper and lower heart chambers on the right and left sides of the heart (tricuspid valve on the right and mitral valve on the left). Normally, the developing heart has a common valve between the upper and lower chambers of the heart, called an atrioventricular valve. This valve divides and separates to form the tricuspid and mitral valves.

With AVSD, the common valve does not develop into the tricuspid and mitral valves. Thus, an atrioventricular valve persists and prevents the atrial septum and ventricular septum from forming properly, leaving a hole in the atrial septum (atrial septal defect, ASD) and a hole in the ventricular septum (ventricular septal defect, VSD). 

The ASD and VSD allow for blood to flow from the left side (area of high pressure) to the right side of the heart (area of low pressure). Long term, if the AVSD is not repaired, the added blood flow increases the pressure in the blood vessels of the lungs. This condition is called pulmonary hypertension (abnormally high blood pressure in the lungs).

The added flow and abnormally high pressure in the lungs can cause the heart to work harder. Over time, congestive heart failure develops. Signs of congestive heart failure can include blue or cyanotic lips, nails and skin, fast breathing, sweating when feeding, feeding difficulty and poor weight gain.

Reference image of the defect (Image courtesy of CDC)

Tetralogy of Fallot (TOF)

Tetralogy of Fallot is a condition made up of the following 4 defects:

 

1. Ventricular Septal Defect (VSD)

A ventricular septal defect (VSD) is a hole or opening in the septum or wall between the two lower heart chambers (right ventricle and left ventricle). Typically, the blood pressure in the left ventricle is about 5 times higher than the blood pressure in the right ventricle. With this open communication between the two ventricles, the blood flows from the left ventricle (area of high pressure) to the right ventricle (area of low pressure). See above for further details.

 

2. Pulmonary Stenosis

Pulmonary stenosis is a narrowing or obstruction of the pulmonary artery, the large blood vessel from the right ventricle to the lungs. This narrowing or obstruction can occur below the pulmonary valve, within the pulmonary valve, or above the valve. See section on Pulmonary Stenosis below for further details.

 

3. Overriding Aorta

The aorta is the large blood vessel that delivers oxygen-rich blood from the left ventricle to the body. In this condition, the aorta is abnormally positioned between the right and left ventricle, just above the ventricular septal defect

 

4. Right Ventricular Hypertrophy

Right ventricular hypertrophy is thickening of the walls of the right ventricle. Normally, the muscular walls are thin. However, the pulmonary stenosis and overriding aorta forces the right ventricle to pump against higher than normal pressure, causing the right ventricular walls to thicken.

With these four defects, the oxygen-poor blood is limited or unable to travel through to the lungs (pulmonary stenosis) and instead travels through the ventricular septal defect or directly through the overriding aorta, causing the oxygen-poor blood from the right ventricle and the oxygen-rich blood from the left ventricle to mix and travel out to the body. If the pulmonary stenosis is severe, the child will have an abnormal oxygen saturation and appear cyanotic or “blue”, often seen in the lips and nails. In severe cases, the child may experience a “Tet spell”, an episode in which the child becomes cyanotic when irritable or crying, and then becomes sleepy or unresponsive. If this occurs, seek immediate medical attention.

The linked KHAN ACADEMY® video lecture explains Tetralogy of Fallot in an easy to understand way: View here

Transposition of the Great Arteries (TGA)

There are 2 types of transposition of the great arteries – D-type and L-type.

D-type transposition of the great arteries involves the aorta and the pulmonary artery, the two large blood vessels that carry blood out of the heart, being in the wrong positions. Normally, the left ventricle delivers oxygen-rich blood to the body through the aorta, and the right ventricle delivers oxygen-poor blood through the pulmonary artery to the lungs.

With transposition of the great arteries, the aorta is located where the pulmonary artery should be. Thus, the right ventricle pumps the oxygen-poor blood through the aorta and out to the body. The pulmonary artery is located where the aorta should be, causing the left ventricle to send the oxygen-rich blood to the lungs. Infants with this condition will become cyanotic or blue at birth or soon after birth because the oxygen-rich blood is not properly delivered to the body.

The timing of when the infant becomes cyanotic will depend on whether or how long 2 points of communication, the patent foramen ovale (PFO) and the patent ductus arteriosus (PDA), remain open after birth. The patent foramen ovale is a hole in the wall of the atria, the two upper heart chambers. The PFO typically closes soon after birth when the pressure in the blood vessels of the lungs drops. The ductus arteriosus is a blood vessel that connects the main pulmonary artery (blood vessel from the right ventricle to the blood vessels in the lungs) to the aorta. Similar to the PFO, the PDA typically closes soon after birth. If the PFO and PDA remain open, the oxygen-rich blood coming back from the lungs to the left atrium will travel through the PFO to the right atrium, mixing the oxygen-rich blood with the oxygen-poor blood. This mix of blood then travels through the right ventricle and out to the body through the aorta.

A ventricular septal defect or coarctation of the aorta may occur with TGA. Abnormalities of the coronary arteries (blood vessels that deliver blood to the heart) may also occur with TGA.

With this heart defect, the infant may have one or all of the following symptoms: blue or cyanotic lips, nails and skin, fast breathing, feeding difficulty or poor weight gain. 

L-type transposition of the great arteries is a heart defect in which the right ventricle and the left ventricle are in opposite positions. The oxygen-poor blood returns to the right atrium and drains into left ventricle, the chamber just below it. The left ventricle then pumps the blood into the pulmonary artery through to the lungs. The oxygen-rich blood then returns from the lungs to the left atrium and drains into the right ventricle, which then pumps the blood through the aorta out to the body. Though the blood is traveling through the proper channels, allowing for proper oxygenation for the child, the right ventricle is pumping against the high pressures of the body. Over time, the right ventricular, designed to pump against the much lower pressures, can develop thickened walls (hypertrophy) and become enlarged or dilated. When this occurs, the ventricle becomes dysfunctional and eventually, heart failure develops. The child may have symptoms of fast breathing, feeding difficulty or poor weight gain. Ventricular septal defect and pulmonary stenosis are some heart defects that can occur with L-type TGA.

The linked KHAN ACADEMY® video lecture explains Transposition of great arteries in an easy to understand way: View here

Partial Anomalous Pulmonary Venous Connection or Return (PAPVR)

Typically, two pulmonary veins connect the right lung to the left atrium (left upper heart chamber) and two pulmonary veins connect the left lung to the left atrium, allowing for the oxygen-rich blood to travel through to the left side of the heart and out to the body.

In this heart defect, one or more (but not all) pulmonary veins abnormally connects to blood vessels or to the right atrium (right upper chamber of the heart) instead of the left atrium. The most common type of PAPVR involves one or both right pulmonary veins.

This heart defect typically does not cause any symptoms. However, if the few pulmonary veins abnormally connecting to the right side of the heart delivers too much blood through this pathway, the extra blood flow going through the right atrium and right ventricle can cause these chambers to enlarge. If this occurs, then surgery to repair this defect is indicated.

Tricuspid Atresia

Tricuspid atresia involves three different abnormalities:

-The tricuspid valve, the valve between the right upper and lower chamber of the heart, is absent, so there is no communication between the right atrium (upper chamber) and the right ventricle (lower chamber).

-The right ventricle (lower chamber) is abnormally small (hypoplastic).

-Presence of an atrial septal defect, a hole between the top two chambers of the heart (right atrium and left atrium).

With tricuspid atresia, since the oxygen-poor blood in the right atrium cannot travel to the right ventricle, the blood travels through the atrial septal defect to the left atrium, here the oxygen-poor blood mixes with the oxygen-rich blood, and eventually travels out to the body. The child will show signs of cyanosis with blue/purple lips, nails and skin.

A ventricular septal defect, a hole between the lower two chambers of the heart (right ventricle and left ventricle) is commonly also present with tricuspid atresia. If this defect is present, the mixed blood travels down from the left atrium into the left ventricle and through the ventricular septal defect into the right ventricle. If there is too much blood flow through the right ventricle and out into the lungs, the right ventricle may not be able to keep up with the extra work, leading to heart failure. The child may display symptoms of fast breathing, feeding intolerance, poor appetite, and poor weight gain.

Pulmonary stenosis (narrowing or blockage above, below or at the level of the pulmonary valve) can also occur with tricuspid atresia with a ventricular septal defect. If the narrowing or blockage is severe, little to no blood will travel from the right ventricle into the lungs. The child’s oxygen saturation or oxygen level will be very low. 

Transposition of the great arteries (the two large blood vessels that extend out from the heart are on opposite sides) can also occur with tricuspid atresia.

The linked KHAN ACADEMY® video lecture explains Tricuspid Artresia in an easy to understand way: View here

Pulmonary atresia

With pulmonary atresia, the pulmonary valve, located between the right lower heart chamber (right ventricle) and the blood vessel delivering blood to the lungs (pulmonary artery) does not form properly, so the blood cannot pass through to the lungs.

Pulmonary atresia can occur with or without a ventricular septal defect, a hole between the lower two heart chambers (the right ventricle and left ventricle).

Pulmonary Atresia with Ventricular Septal Defect (VSD)

This defect is considered to be Tetralogy of Fallot with Pulmonary Atresia. The oxygen-poor blood coming into the right atrium (right upper heart chamber) travels to the right ventricle (right lower heart chamber), then passes through the ventricular septal defect (hole in the wall between the right and left lower heart chambers) and mixes with the oxygen-rich blood in the left ventricle (left lower heart chamber). This mixed blood then travels out to the body.

Alternative routes for the oxygen-poor blood to travel to the lungs must be present to provide a continued supply of oxygen-rich blood to the body. These routes include an open or patent ductus arteriosus, a small blood vessel that connects the main pulmonary artery (blood vessel from the right ventricle to the blood vessels in the lungs) to the aorta (blood vessel from the left ventricle to the body). If the ductus arteriosus does not exist, large blood vessels called major aorto-pulmonary collateral arteries (MAPCAs) develop connecting the aorta to the blood vessels (pulmonary arteries) in the lungs.

The child with pulmonary atresia and a ventricular septal defect may have one or all of the following symptoms: cyanosis or blue/purple lips, nails or skin, shortness of breath, or difficulty feeding with poor weight gain.

Pulmonary Atresia with Intact Ventricular Septum

In this heart defect, the pulmonary valve does not form properly and there is no open communication between the lower two heart chambers. Additionally, the right lower heart chamber (right ventricle) and the tricuspid valve, the valve between the right upper and lower heart chambers, are abnormally small. This heart defect is also called hypoplastic right ventricle.

When the oxygen-poor blood returns to the heart to the right upper chamber (right atrium), it will travel down through the tricuspid valve into the small right lower chamber (right ventricle). Since the pulmonary valve is not formed, the blood cannot travel from the right ventricle into the lungs. Thus, the blood passes through the foramen ovale, a hole between the two upper heart chambers (right atrium and left atrium).

The foramen ovale is always open before birth. In a normal heart, the foramen ovale often closes when the pressures on the right side of the heart drops soon after birth. In pulmonary atresia with an intact ventricular septum, the oxygen-poor blood returns to heart into the right atrium, then through the patent (or open) foramen ovale and into the left upper heart chamber (left atrium), mixing with the oxygen-rich blood in the left atrium, and eventually travels out to the body. The lung receives oxygen-rich blood from the aorta, the large blood vessel that sends blood out to the body, through the ductus arteriosus, a small blood vessel connecting the aorta with the pulmonary artery.

Since the oxygen-poor blood and oxygen-rich blood mixes in the left side of the heart, the child will be cyanotic with blue or purple lips, nails and skin.

Immediate medical attention is needed to keep the ductus arteriosus and the foramen ovale open.

Reference image of the defect (Image courtesy of CDC)

Pulmonary Stenosis

Pulmonary stenosis is a narrowing or obstruction of the pulmonary artery, the large blood vessel from the right lower heart chamber (right ventricle) to the lungs. This narrowing or obstruction can occur below the pulmonary valve, within the pulmonary valve, or above the valve.

Pulmonary stenosis below the pulmonary valve, also known as subvalvar or subpulmonic stenosis, involves part of the right ventricle’s muscle that is called the right ventricular outflow tract. The muscle is abnormally thick in this area, causing narrowing of the outflow tract.

Pulmonary stenosis after the pulmonary valve can occur immediately above the pulmonary valve (supravalvar pulmonary stenosis). If the stenosis occurs further along the smaller branches of the pulmonary artery, the defect is called peripheral pulmonary artery stenosis or branch pulmonary artery stenosis.

Regardless of the location, the stenosis makes it difficult for the blood to travel from the right ventricle to the pulmonary artery, increasing the workload on the right ventricle. If the narrowing or obstruction is mild, the child may have few concerning symptoms. If the stenosis is severe and left untreated, heart failure may occur. The child may have symptoms of increased work of breathing, difficulty feeding or poor weight gain.

Aortic Valve Stenosis

In a normal heart, the oxygen-rich blood travels from the left lower heart chamber (left ventricle) through the aortic valve, then through the aorta (large blood vessel) and out to the rest of the body. The aortic valve is made up of three leaflets (tricuspid). The leaflets open when the heart pumps to let the blood through and closes when the heart relaxes. When the valve closes, the blood cannot go back into the left ventricle.

With aortic valve stenosis, the valve does not form properly. The valve leaflets may be stuck together, so the valve does not open up properly. The valve may be have two leaflets (bicuspid) instead of three leaflets. Alternatively, the valve may be abnormally small or hypoplastic. With all three types of issues, the valve does not work properly and allows for the blood that goes through the valve to leak back or regurgitate when the valve is supposed to be closed.

If the aortic valve stenosis or narrowing is severe, extra blood accumulates in the left ventricle. The ventricle also must work harder to pump the blood through the valve, causing it to become tired. Heart failure may develop. In this instance, the child will have symptoms of fast breathing, feeding difficulty, fast heart rate (tachycardia) and low blood pressure.

The linked KHAN ACADEMY® video lecture explains Aortic Valve Stenosis in an easy to understand way: View here

Mitral Valve Stenosis

In a normal heart, the oxygen-rich blood travels from the left upper heart chamber (left atrium) down to the left lower heart chamber (left ventricle) through the mitral valve. This valve is made up of 2 leaflets (bicuspid) that opens when the heart relaxes and closes when the heart contracts.

With mitral valve stenosis, the valve is narrowed or tight. The stenosis does not allow the blood to flow normally from the left atrium to the left ventricle and out to the body. The blood backs up into the left atrium. The blood further backs up into the lungs, increasing the blood pressure in the lungs, a condition known as pulmonary hypertension. Over time, the pulmonary hypertension will force the right lower heart chamber (right ventricle) to work hard against the abnormally high pressures in the lungs. The right ventricle may eventually become tired and go into heart failure. The child may have symptoms of increased work of breathing, difficulty feeding or poor weight gain.

The linked KHAN ACADEMY® video lecture explains Mitral Valve Stenosis in an easy to understand way: View here

Mitral Valve Prolapse

In a normal heart, the oxygen-rich blood travels from the left upper heart chamber (left atrium) down to the left lower heart chamber (left ventricle) through the mitral valve. This valve is made up of two leaflets (bicuspid) that open when the heart relaxes and closes when the heart contracts.

With mitral valve prolapse, one of the two leaflets prolapses or extends back into the left atrium, so the valve does not properly close. This defect will cause mitral regurgitation, meaning the blood leaks back to the left atrium when the left ventricle contracts.

In most cases, the child does not have any symptoms. This heart defect is usually diagnosed during adolescence or early adulthood. It does not require any surgical intervention.

The linked KHAN ACADEMY® video lecture explains Mitral Valve Prolapse in an easy to understand way: View here

CREDITS

 

Michelle Ogawa

Certified Pediatric Nurse Practitioner (CPNP)

 

Ann Kumar, MSN(c), NCSN

Registered Nurse

 

Center for Disease Control and Prevention (CDC)

 

Dr Anita Saxena, Dean (Academics), Chief, Cardio-Thoracic Centre

Professor and Head,Department of Cardiology, All India Institute of Medical Sciences New Delhi

 

Khan Academy

The KHAN ACADEMY® website is located at www.khanacademy.org

Note: All Khan Academy content is available for free at (www.khanacademy.org)

 

Mayo Clinic

Health information from Mayo Clinic is located at www.mayoclinic.org

Mayo Clinic is a trademark of Mayo Foundation for Medical Education and Research.

 

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Saloni Heart Foundation

Saloni Heart Foundation (SHF) is a non-profit organization solely funded by donor contributions. The services provided by SHF and participating physicians are free of charge. SHF will work to facilitate a second opinion by a participating leading pediatric cardiologist. The decision by participating parents or legal guardians to accept or reject the course of action prescribed by the SHF consulting physician is independent from the services provided by SHF herein. SHF acts as a conduit for these services and does not receive any compensation in any circumstances, including if parents or legal guardians retain the services of participating physicians.

Email: admin@saloniheartfoundation.org

Phone: +1-650-770-5000 (Whatsapp)

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Registered as a non-profit under sec 501(c) (3) of the IRS Code

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