Critical congenital heart diseases

CRITICALCONGENITAL HEART DISEASES

VAISHNAVI SURESH NAIR

CONTENTS: OBJECTIVES IMPORTANCE STATISTICS OF CHD IN GENERAL CCHD SCREENING FOR CCHD RISK FACTORS MORE ABOUT:

• Hypoplastic left heart syndrome• Pulmonary atresia with intact septum

• Tetralogy of Fallot• Total anomalous pulmonary venous return

• d-Transposition of the great arteries• Tricuspid atresia• Truncus arteriosus

PROGNOSIS REFERENCES

OBJECTIVES: TO DISCUSS THE RELEVANE OF CCHD IN THE PRESENT. TO DISCUSS THE IMPORTANCE OF SCREENING THE NEW-BORNS FOR CCHD. TO UNDERSTAND THE EXISTING , KNOWN RISK FACTORS FOR CCHD. TO PROVIDE GENERAL INFORMATION ABOUT CCHDs. TO UNDERSTAND MORE ABOUT THE CCHDs CONSIDERED AS THE PRIMARY SCREENING

TARGETS.

IMPORTANCEHeart defects are the most common type of birth defect, accounting for more than 30 percent of all infant deaths due to birth defects. CCHD represents some of the most serious types of heart defects. About 7,200 new-borns, or 18 per 10,000, in the United States are diagnosed with CCHD each year.

Congenital heart defects (CHDs) are the most common types of birth defects, and babies born with these conditions are living longer and healthier lives. Number of U.S. Babies Born with CHDs:•CHDs affect nearly 1% of―or about 40,000―births per year in the United States.

•The prevalence (the number of babies born with heart defect compared to the total number of births) of some CHDs, especially mild types, is increasing, while the prevalence of other types has remained stable. The most common type of heart defect is a ventricular septal defect (VSD).

•About 25% of babies with a CHD have a critical CHD. Infants with critical CHDs generally need surgery or other procedures in their first year of life.

STATISTICS:

Number of U.S. Children and Adults Living with CHDs:

One study estimated that, in 2010, about 2 million infants, children, adolescents, and adults were living with CHDs in the United States. Researchers estimated that about 1 million U.S. children and about 1 million U.S. adults were living with CHDs.  

Overall, there are slightly more adults living with CHDs than children.

( To obtain this estimate, researchers used data from administrative healthcare databases in Canada to estimate the prevalence of people living with CHDs and applied this to the U.S. Census data from 2010 )

CHD-Related Deaths•CHDs are a leading cause of birth defect-associated infant illness and death.

•Infant deaths due to CHDs often occur when the baby is less than 28 days old (sometimes called the neonatal period).

•In a study of neonatal deaths, 4.2% of all neonatal deaths were due to a CHD.

•During 1999–2006, there were 41,494 deaths related to CHDs in the United States.

This means that CHDs were either the main cause of death or contributed to death in some way. During this time period, CHDs were listed as the main cause of death for 27,960 people. Nearly half (48%) of the deaths due to CHDs occurred during infancy (younger than 1 year of age).

SURVIVAL:•Survival of infants with CHDs depends on how severe the defect is, when it is diagnosed, and how it is treated.

NON-CRITICAL CHD:•About 97% of babies born with a non-critical CHD are expected to survive to one year of age. •Thus, the population of people with CHDs is growing.

CRITICAL CHD:•About 75% of babies born with a critical CHD are expected to survive to one year of age. •Survival and medical care for babies with critical CHDs are improving. •Between 1979 and 1993, about 67% of infants with critical CHDs survived to one year. •Between 1994 and 2005, about 83% of infants with critical CHDs survived to one year.

Illness and Disability•At least 15% of CHDs are associated with genetic conditions.

•About 20% to 30% of people with a CHD have other physical problems or developmental or cognitive disorders.

•Children with CHD are about 50% more likely to receive special education services compared to children without birth defects.

•The occurrence and severity of a developmental disability or delay increases with how complex the heart defect is.

For example, more than 80% of individuals with a mild CHD have no developmental disabilities. However, more than half of those with a more critical type of CHD have some form of disability or impairment.

Guidelines for screening, diagnosing, and managing developmental disabilities or delay in children with CHDs have recently been developed.

About 1 in every 4 babies born with a heart defect has a critical congenital heart defect (CCHD)

Typically, these types of heart defects lead to low levels of oxygen in a newborn and may be identified using pulse oximetry screening at least 24 hours after birth.

Babies with a critical CHD need surgery or other procedures in the first year of life.

CRITICAL CONGENITAL HEART DISEASES

Some Specific Critical CHDs:• Coarctation of the aorta• Double-outlet right ventricle• Ebstein’s anomaly• Interrupted aortic arch• Single ventricle

•Hypoplastic left heart syndrome•Pulmonary atresia with intact septum•Tetralogy of Fallot•Total anomalous pulmonary venous return•d-Transposition of the great arteries•Tricuspid atresia•Truncus arteriosus

Some CHDs may be diagnosed during pregnancy using foetal-echocardiogram.However, some heart defects are not found during pregnancy. In these cases, heart defects may be detected at birth or as the child ages.

Some babies born with a critical CHD appear healthy at first, and they may be sent home before their heart defect is detected. These babies are at risk of having serious complications within the first few days or weeks of life, and often require emergency care.

Newborn screening is a tool that can identify some of these babies so they can receive prompt care and treatment.

Timely care may prevent disability or death early in life.

Importance of Newborn Screening for Critical CHDs

SCREENING

Timing of Critical CHD Screening:Screening is done when a baby is at least 24 hours of age, or as late as possible if the baby is to be discharged from the hospital before he or she is 24 hours of age.

How Newborn Screening for Critical CHDs is Done?

Newborn screening for critical CHDs involves pulse oximetry. Low levels of oxygen in the blood can be a sign of a critical CHD.

Pulse oximetry screening does not replace a complete history and physical examination, which sometimes can detect a critical CHD before oxygen levels in the blood become low.

Pulse oximetry screening, therefore, should be used along with the physical examination

Percentages refer to oxygen saturation as measured by pulse oximeter. 

Algorithm showing the

steps in screening.

Includes 7 primary targets and 5 secondary targets. Pulse oximetry screening is most likely to detect the 7 primary screening targets, which almost always produce hypoxemia in the blood. The secondary targets, which are less likely to produce hypoxemia, can be detected via pulse oximetry screening, but not as consistently as the primary screening targets.

The targets for critical CHD screening:

Primary Screening Targets•Hypoplastic left heart syndrome•Pulmonary atresia with intact septum•Tetralogy of Fallot•Total anomalous pulmonary venous return•d-Transposition of the great arteries•Tricuspid atresia•Truncus arteriosus

Secondary Screening Targets•Coarctation of the aorta•Double outlet right ventricle•Ebstein anomaly•Interrupted aortic arch•Single ventricle

Failed ScreensA screen is considered failed if1.Any oxygen saturation measure is <90% (in the initial screen or in repeat screens),2.Oxygen saturation is <95% in the right hand and foot on three measures, each separated by one hour, or3.A >3% absolute difference exists in oxygen saturation between the right hand and foot on three measures, each separated by one hour.

Any infant who fails the screen should have a diagnostic echocardiogram, which would involve either an echocardiogram within the hospital or birthing center, transport to another institution for the procedure, or use of telemedicine for remote evaluation. The infant’s paediatrician should be notified immediately and the infant might need to be seen by a cardiologist.

Passed ScreensAny screening with an oxygen saturation measure that is ≥95% in the right hand or foot with a ≤3% absolute difference between the right hand or foot is considered a passed screen and screening would end. Pulse oximetry screening does not detect all critical CHDs, so it is possible for a baby with a passing screening result to still have a critical CHD or other CHD.

Ways to Reduce False Positive Screens:

•Screen the newborn while he or she is alert.•Screen the newborn when he or she is at least 24 hours old.

RISK FACTORS:In most cases, the cause of CCHD is unknown. A variety of genetic and environmental factors likely contribute to this complex condition.

Changes in these genes are associated with critical congenital heart disease:CFC1,FOXH1,GATA4,GATA6,GDF1,GJA1,HAND1,MED13L,NKX2-5,NKX2-6,NOTCH1,SMAD6,ZFPM2

The heart defects associated with CCHD can also occur as part of genetic syndromes that have additional features. Some of these genetic conditions, such as Down syndrome, Turner syndrome, and 22q11.2 deletion syndrome, result from changes in the number or structure of particular chromosomes. Other conditions, including Noonan syndrome and Alagille syndrome, result from mutations in single genes.

Environmental factors may also contribute to the development of CCHD. (No sufficient data to particularize)

Potential risk factors that have been studied include exposure to certain chemicals or drugs before birth, viral infections (such as rubella and influenza) that occur during pregnancy, and other maternal illnesses including diabetes and phenylketonuria. Although researchers are examining risk factors that may be associated with this

complex condition, many of these factors remain unknown.

HYPOPLASTIC LEFT HEART SYNDROMEHypoplastic left heart syndrome (HLHS) is a birth defect that affects normal blood flow through the heart. As the baby develops during pregnancy, the left side of the heart does not form correctly.

Hypoplastic left heart syndrome affects a number of structures on the left side of the heart that do not fully develop, for example:

•The left ventricle is underdeveloped and too small.•The mitral valves is not formed or is very small.•The aortic valve is not formed or is very small.•The ascending portion of the aorta is underdeveloped or is too small.•Often, babies with hypoplastic left heart syndrome also have an atrial septal defect.

PATHOPHYSIOLOGY:

In babies with hypoplastic left heart syndrome, the left side of the heart cannot pump oxygenated blood to the body properly. During the first few days of life for a baby with hypoplastic left heart syndrome, the oxygenated blood bypasses the poorly functioning left side of the heart through the patent ductus arteriosus and the patent foramen ovale. The right side of the heart then pumps blood to both the lungs and the rest of the body. However, among babies with hypoplastic left heart syndrome, when these openings close, it becomes hard for oxygenated blood to get to the rest of the body.INCIDENCE:The Centers for Disease Control and Prevention (CDC) estimates that each year about 960 babies in the United States are born with hypoplastic left heart syndrome. In other words, about 1 out of every 4,344 babies born in the United States each year is born with hypoplastic left heart syndrome.

SIGNS & SYMPTOMS:• Respiratory distress• Shock or mild cyanosis• A systolic ejection murmur may be heard at the ULSB due to increased flow through the

pulmonary valve. • A holosystolic murmur due to Tricuspid Regurgitation may be heard. • S2 is unusually loud and single. • The peripheral pulses may be weak and the skin may be mottled due to poor tissue

perfusion.

DIAGNOSIS:

•This condition can be diagnosed prenatally as early as 16 weeks gestation.•EKG: there is absent Q wave in V6, poor progression of LV forces and RV myocardial ischemic ST-T wave changes.•Echocardiography is diagnostic and also helps to determine the size of the inter-atrial communication, the patency of the ductus arteriosus, RV function and the presence of TR.•CXR shows cardiomegaly, pulmonary venous congestion and pulmonary edema.•Cardiac catheterization is rarely necessary for diagnosis but may urgently be needed to perform balloon atrial septostomy if the ASD is restrictive.

TREATMENTS:Medical management: PGE-1 should be started to maintain the ductal patency. Avoid oxygen supplementation because this causes pulmonary vasodilatation and lowers the PVR, which makes pulmonary congestion and CHF worse. Avoid excessive administration of IVF as most of the fluid will to go to the lungs. Also avoid high doses of inotropic agents as these (a) cause systemic vasoconstriction, (b) increase the SVR, which accentuates tissue hypo-perfusion and metabolic acidosis; and (c) increase the myocardial oxygen demand.Nutrition:Some babies with hypoplastic left heart syndrome become tired while feeding and do not eat enough to gain weight. To make sure babies have a healthy weight gain, a special high-calorie formula might be prescribed. Some babies become extremely tired while feeding and might need to be fed through a feeding tube.Surgery:Soon after a baby with hypoplastic left heart syndrome is born, multiple surgeries done in a particular order are needed to increase blood flow to the body and bypass the poorly functioning left side of the heart. The right ventricle becomes the main pumping chamber to the body. These surgeries do not cure hypoplastic left heart syndrome, but help restore heart function. Sometimes medicines are given to help treat symptoms of the defect before or after surgery. Surgery for hypoplastic left heart syndrome usually is done in three separate stages:1.Norwood Procedure, 2.Bi-directional Glenn Shunt Procedure, 3. Fontan Procedure.

PULMONARY ATRESIA WITH INTACT SEPTUM

PATHOPHYSIOLOGY:In babies with pulmonary atresia, the pulmonary valve that usually controls the blood flowing through the pulmonary artery is not formed, so blood is unable to get directly from the right ventricle to the lungs.In pulmonary atresia, since blood cannot directly flow from the right ventricle of the heart out to the pulmonary artery, blood must use other routes to bypass the unformed pulmonary valve.  The foramen ovale, that usually closes after the baby is born, often remains open to allow blood flow to the lungs.

Additionally, doctors may give medicine to the baby to keep the baby’s ductus arteriosus open after the baby’s birth.

Pulmonary atresia is a birth defect of the pulmonary valve, which is the valve that controls blood flow from the right ventricle to the main pulmonary artery. Pulmonary atresia is when this valve didn’t form at all, and no blood can go from the right ventricle of the heart out to the lungs. In babies with this defect, blood has trouble flowing to the lungs to pick up oxygen for the body.

Types of Pulmonary Atresia:

•Pulmonary atresia with an intact ventricular septum: 

In this form of pulmonary atresia, the septum between the ventricles remains complete and intact.  During pregnancy when the heart is developing, very little blood flows into or out of the right ventricle, and therefore the RV doesn’t fully develop and remains very small.  If the RV is under-developed, the heart can have problems pumping blood to the lungs and the body. The main pulmonary artery (MPA), remains very small, since the pulmonary valve (PV) doesn’t form.

•Pulmonary atresia with a ventricular septal defect: 

In this form of pulmonary atresia, a ventricular septal defect (VSD) allows blood to flow into and out of the right ventricle (RV). Therefore, blood flowing into the RV can help the ventricle develop during pregnancy, so it is typically not as small as in pulmonary atresia with an intact ventricular septum. Pulmonary atresia with a VSD is similar to another condition called tetralogy of Fallot.

However, in tetralogy of Fallot, the pulmonary valve (PV) does form, although it is will have pulmonary valve stenosis.  Thus, pulmonary atresia with a VSD is like a very severe form of tetralogy of Fallot. 

INCIDENCE:In a 2012 study using data from birth defects tracking systems across the United States, researchers estimated that about 1 out of every 10,000 babies is born with pulmonary atresia.Signs and SymptomsBabies born with pulmonary atresia will show symptoms at birth or very soon afterwards. They may have a bluish looking skin color, called cyanosis, because their blood doesn’t carry enough oxygen. Infants with pulmonary atresia can have additional symptoms such as:•Problems breathing•Ashen or bluish skin color•Poor feeding•Extreme sleepiness•Patients are severely cyanotic and have respiratory distress. The S2 is single and a PDA murmur may be heard DIAGNOSIS:EKG shows RAE, LVH and possibly RVH.CXR shows the pulmonary vasculature is usually reduced.

TreatmentMost babies with pulmonary atresia will need medication to keep the ductus arteriosus open after birth. Keeping this blood vessel open will help with blood flow to the lungs until the pulmonary valve can be repaired.Treatment for pulmonary atresia depends on its severity. In some cases, blood flow can be improved by using cardiac catheterization, ballooning and stenting.

In most cases of pulmonary atresia, a baby may need surgery soon after birth. During surgery, doctors widen or replace the pulmonary valve and enlarge the passage to the pulmonary artery. If a baby has a VSD, the doctor also will place a patch over the VSD to close the hole between the two lower chambers of the heart. These actions will improve blood flow to the lungs and the rest of the body. If a baby with pulmonary atresia has an underdeveloped right ventricle, he or she might need staged surgical procedures, similar to surgical repairs for HLHS.

TETRALOGY OF FALLOTTetralogy of Fallot is a birth defect that affects normal blood flow through the heart. It happens when a baby’s heart does not form correctly as the baby grows and develops in the mother’s womb during pregnancy.

Tetralogy of Fallot is made up of the following four defects of the heart and its blood vessels:1.A hole in the wall between the two lower chambers―or ventricles―of the heart. This condition also is called a ventricular septal defect.2.A narrowing of the pulmonary valve and main pulmonary artery. This condition also is called pulmonary stenosis.3.The aortic valves, which opens to the aorta, is enlarged and seems to open from both ventricles, rather than from the left ventricle only, as in a normal heart. In this defect, the aortic valve sits directly on top of the ventricular septal defect.4.The muscular wall of the lower right chamber of the heart (right ventricle) is thicker than normal. This also is called ventricular hypertrophy.

SIGNS & SYMPTOMS:This heart defect can cause oxygen in the blood that flows to the rest of the body to be reduced. Infants with tetralogy of Fallot can have cyanosis. At birth, infants might not have cyanosis, but later might develop sudden episodes of bluish skin during crying or feeding. These episodes are called tet spells. Infants with tetralogy of Fallot or other conditions causing cyanosis can have problems including:•A higher risk of getting an infection of the layers of the heart, called endocarditis.•A higher risk of having irregular heart rhythms, called arrhythmia.•Dizziness, fainting, or seizures, because of the low oxygen levels in their blood.•Delayed growth and development.There is a right ventricular tap at the left sternal border, systolic ejection murmur due to RVOTO, and single S2. The VSD is usually unrestrictive and does not produce a heart murmur.

INCIDENCE & PREVALENCE:The Centers for Disease Control and Prevention (CDC) estimates that each year about 1,660 babies in the United States are born with tetralogy of Fallot. In other words, about 1 in every 2518 babies born in the United States each year are born with tetralogy of Fallot.

TREATMENTS:Tetralogy of Fallot can be treated by surgery soon after the baby is born.

During surgery, doctors widen or replace the pulmonary valve and enlarge the passage to the pulmonary artery. They also will place a patch over the ventricular septal defect to close the hole between the two lower chambers of the heart.

These actions will improve blood flow to the lungs and the rest of the body. Most infants will live active, healthy lives after surgery.

Diagnosis•EKG: Right Axis Deviation, Right Ventricular Hypertrophy.•CXR: 'Boot shaped' heart, due to concave main pulmonary artery segment and upturned RV apex due to RVH.•Echocardiography: diagnostic. 25% of patients have right aortic arch and 5% have coronary artery anomalies.

TOTAL ANOMALOUS PULMONARY VENOUS RETURN

Total anomalous pulmonary venous return (TAPVR), or connection (TAPVC) is a birth defect of the heart in which the pulmonary veins don’t connect to the left atrium like usual. Instead they go to the heart by way of an abnormal (anomalous) connection. In a related defect, partial anomalous pulmonary venous return (PAPVR), not all of the veins have an abnormal connection. There are some abnormal connections, but one or more of the veins return normally to the left atrium. Therefore, PAPVR is not as critical as TAPVR.

PATHOPHYSIOLOGY:In a baby with TAPVR, oxygenated blood does not return from the lungs to the left atrium. Instead, the oxygenated blood returns to the right side of the heart. Here, oxygenated blood mixes with de-oxygenated blood. This causes the baby to get less oxygen than is needed to the body. To survive with this defect, babies with TAPVR usually have a hole between the right atrium and the left atrium (an atrial septal defect) that allows the mixed blood to get to the left side of the heart and pumped out to the rest of the body.

Some children can have other heart defects along with TAPVR, aside from the atrial septal defect.

INCIDENCE:CDC estimates that together, TAPVR and PAPVR occur in about one out of every 10,000 births.

Types of TAPVR:

There are different types of TAPVR, based on where the pulmonary veins connect:•Supracardiac– In supracardiac TAPVR, the pulmonary veins come together and form an abnormal connection above the heart to the superior venacava. In this type of TAPVR, a mixture of Oxygenated & deoxygenated blood returns to the right atrium through the superior venacava.

•Cardiac – In cardiac TAPVR, the pulmonary veins meet behind the heart and connect to the right atrium. The coronary sinus, helps connect the pulmonary veins to the right atrium in this type of TAPVR.

•Infracardiac – In infracardiac TAPVR, the pulmonary veins come together and form abnormal connections below the heart. A mixture of oxygenated & deoxygenated blood returns to the right atrium from the veins of the liver and the inferior venacava.

SIGNS & SYMPTOMS:Symptoms usually occur at birth or very soon afterwards. Infants with TAPVR can have cyanosis. Infants with TAPVR can have symptoms such as:•Problems breathing•Pounding heart•Weak pulse•Ashen or bluish skin color•Poor feeding•Extreme sleepinessWe can often hear a heart murmur (caused by blood flowing through the atrial septal defect).  However, it is not uncommon for a heart murmur to be absent right at birth.

TreatmentMedical management may be tried in patients with TAPVC without obstruction, in the form of diuretics, digoxin and correction of metabolic acidosis. PGE-1 causes pulmonary vasodilatation and may worsen the CHF and should be avoided.Babies with TAPVR will need surgery to repair the defect. The age at which the surgery is done depends on how sick the child is and the specific structure of the abnormal connections between the pulmonary veins and the right atrium.

The goal of the surgical repair of TAPVR is to restore normal blood flow through the heart. To repair this defect, surgeons usually connect the pulmonary veins to the left atrium, close off any abnormal connections between blood vessels, and close the atrial septal defect.

Diagnosis:

•CXR shows near normal sized heart and pulmonary edema.•Cardiomegaly with a "snowman" sign in supra-cardiac type.

d - TRANSPOSITION OF THE GREAT ARTERIES

Dextro-Transposition of the Great Arteries (d-TGA) is a birth defect of the heart in which - the main pulmonary artery and the aorta – are switched in position, or “transposed.”

In transposition of the great arteries, the aorta is in front of the pulmonary artery and is either primarily to the right (dextro) or to the left (levo) of the pulmonary artery. D-TGA is often simply called “TGA.”

However, “TGA” is a broader term that includes both dextro-TGA (d-TGA) and a rarer heart defect called levo-TGA (l-TGA), or congenitally corrected TGA.

PATHOPHYSIOLOGY:In babies with d-TGA, de-oxygenated blood from the body enters the right side of the heart. But, instead of going to the lungs, the blood is pumped directly back out to the rest of the body through the aorta. oxygenated blood from the lungs entering the heart is pumped straight back to the lungs through the main pulmonary artery.Often, babies with d-TGA have other heart defects, such as a ventricular septal defect or an atrial septal defect that allow blood to mix so that some oxygenated blood can be pumped to the rest of the body. The patent ductus arteriosus also allows some oxygenated blood to be pumped to the rest of the body.INCIDENCE:CDC estimates that about 1,250 babies are born with TGA each year in the United States. This means that every 1 in 3,300 babies born in the US is affected by this defect.

SIGNS & SYMPTOMS:Symptoms occur at birth or very soon afterwards. How severe the symptoms are will depend on whether there is a way for blood to mix and for oxygenated blood to get out to the rest of the body.

For example, if an infant with d-TGA has another defect, like an ASD, the ASD forms a passageway for some oxygenated blood to be pumped to the rest of the body. This infant with both d-TGA and an ASD may not have as severe symptoms as infants whose hearts don’t have any mixing of blood.

The physical examination is usually benign except for severe cyanosis and a single loud S2 at the upper left sternal border.• Cyanosis• Problems breathing• Pounding heart• Weak pulse• Ashen or bluish skin color• Poor feeding

Because the infant might be cyanotic and have trouble breathing, d-TGA is usually diagnosed within the first week of life.

Treatments:Medical management includes starting PGE-1 to keep the ductus open and treatment of metabolic acidosis if present.Surgery is required for all babies born with d-TGA. Other procedures may be done before surgery in order to maintain, enlarge or create openings that will allow oxygenated blood to get out to the body.There are two types of surgery to repair d-TGA: Arterial Switch Operation Atrial Switch OperationAfter surgery, medications may be needed to help the heart pump better, control blood pressure, help get rid of extra fluid in the body, and slow down the heart if it is beating too fast. If the heart is beating too slowly, a pacemaker can be used.

Making the Diagnosis•EKG usually shows right axis deviation and right ventricular hypertrophy (RVH).•CXR may have the characteristic egg-shaped appearance (the great arteries are anterior posterior in relationship and the thymus is usually small).•Echocardiogram is diagnostic of dTGA. Echo is also important for identifying sites of communications between the two circulations and in delineating the coronary artery anatomy which is important in surgical repair.•Cardiac catheterization may be needed to perform atrial septostomy; this allows mixing at the atrial level.

TRICUSPID ATRESIA

Tricuspid atresia is a birth defect of the tricuspid valve. Tricuspid atresia occurs when this valve doesn’t form at all, and no blood can go from the right atrium through the right ventricle to the lungs for oxygen.

PATHOPHYSIOLOGY:In babies with tricuspid atresia, the tricuspid valve that controls blood flow from the right atrium to the right ventricle is not formed, so blood is unable to get to the right ventricle and out to the lungs. For this reason, the right ventricle can be underdeveloped.  The main pulmonary artery may also be small with very little blood going through it to the lungs.

In tricuspid atresia, since blood cannot directly flow from the right atrium to the right ventricle, blood must use other routes to bypass the unformed tricuspid valve. Babies born with tricuspid atresia often also have an atrial septal defect or a ventricular septal defect. These defects allow oxygenated blood to mix with de-oxygenated blood, so that oxygenated blood has a way to get pumped to the rest of the body.

Additionally, doctors may give the baby medicine to keep the baby’s patent ductus arteriosus open, after the baby’s birth. Keeping this connection open allows blood to get to the lungs for oxygen and bypass the small right side of the heart.

Some babies with tricuspid atresia can also have other heart defects, including TGA. When a baby has both tricuspid atresia and TGA, blood is able to get to the lungs because the main pulmonary artery arises from the developed left ventricle. 

However, blood cannot get out to the body because the aorta arises from the poorly formed right ventricle and is small. 

Signs and Symptoms:Babies born with tricuspid atresia will show symptoms at birth or very soon afterwards. They may have cyanosis. Infants with tricuspid atresia can have additional symptoms such as:•Problems breathing•Ashen or bluish skin color•Poor feeding•Extreme sleepiness•Have a single S2 and a holosystolic murmur of VSD, and may have a PDA murmur.

DIAGNOSIS:EKG classically shows a left superior axis deviation and diminished RV forces. LVH may be present. Echo is diagnostic.

INCIDENCE:In a 2012 study using data from birth defects surveillance systems across the United States, researchers estimated that about 1 out of every 10,000 babies is born with tricuspid atresia

TreatmentMedicines:Some babies and children will need medicines to help strengthen the heart muscle, lower their blood pressure, and help the body get rid of extra fluid.Management includes IV infusion of PGE-1 to maintain the ductal patency and to treat CHF.

Nutrition:Some babies with tricuspid atresia become tired while feeding and do not eat enough to gain weight. To make sure babies have a healthy weight gain, a special high-calorie formula might be prescribed. Some babies become extremely tired while feeding and might need to be fed through a feeding tube.Surgery:Surgical treatment for tricuspid atresia depends on its severity and presence of other heart defects.  Soon after a baby with tricuspid atresia is born, one or more surgeries may be needed to increase blood flow to the lungs and bypass the poorly functioning right side of the heart. Other surgeries or procedures may be needed later. Surgery do not cure tricuspid atresia, but they help restore heart function. Sometimes medicines are given to help treat symptoms of the defect before or after surgery. Septostomy Banding Shunt Procedure Bi-directional Glenn Procedure Fontan Procedure

TRUNCUS ARTERIOSUS

Truncus arteriosus, also known as common truncus, is a rare defect of the heart in which a single common blood vessel comes out of the heart, instead of the usual two vessels (the main pulmonary artery and aorta).

It occurs when the blood vessel coming out of the heart in the developing baby fails to separate completely during development, leaving a connection between the aorta and pulmonary artery.

There are several different types of truncus, depending on how the arteries remain connected. There is also usually ventricular septal defect present here.

PATHOPHYSIOLOGYIn babies with a truncus arteriosus, de-oxygenated blood and oxygenated blood are mixed together as blood flows to the lungs and the rest of the body. As a result, too much blood goes to the lungs and the heart works harder to pump blood to the rest of the body.

Also, instead of having both an aortic valve and a pulmonary valve, babies with truncus arteriosus have a single common valve (truncal valve) controlling blood flow out of the heart. The truncal valve is often abnormal.

The valve can be thickened and narrowed, which can block the blood as it leaves the heart. It can also leak, causing blood that leaves the heart to leak back into the heart across the valve.

INCIDENCE:Truncus arteriosus occurs in less than one out of every 10,000 live births. It can occur by itself or as part of certain genetic disorders. There are about 300 cases of truncus arteriosus per year in the United States.

SIGNS & SYMPTOMS:

• Mild cyanosis • wide pulse pressure and cardiomegaly• A single S2, ejection systolic murmur (due to increased flow through the truncal valve) • sometimes an apical diastolic murmur (due to increased flow through the mitral valve) • An early diastolic murmur (may indicate truncal valve insufficiency)

Diagnosis:•EKG may show biventricular hypertrophy.•CXR show increased pulmonary vascular markings and prominent ascending aorta and may be suggestive of right aortic arch (25% of cases).•Echo is diagnostic and also shows associated cardiac anomalies.

TreatmentSurgery is needed to repair the heart and blood vessels. This is usually done in the first few months of life. Options for repair depend on how sick the child is and the specific structure of the defect. The goal of the surgery to repair truncus arteriosus is to create a separate flow of de-oxygenated blood to the lungs and oxygenated blood to the body. Some babies with truncus arteriosus also will need medicines to help strengthen the heart muscle, lower their blood pressure, and help their body get rid of extra fluid.

Some babies with truncus arteriosus might become tired while feeding and might not eat enough to gain weight. To make sure babies have a healthy weight gain, a special high-calorie formula might be prescribed. Some babies become extremely tired while feeding and might need to be fed through a feeding tube.Most babies with truncus arteriosus survive the surgical repair, but may need more surgery or other procedures as they get older. For example, the artificial tube doesn’t grow, so it will need to be replaced as the child grows. There also may be blockages to blood flow which may need to be relieved, or problems with the truncal valve.

PROGNOSIS:Infants who have these surgeries are not cured; they may have lifelong complications.

Infants with hypoplastic left heart syndrome will need regular follow-up visits with a cardiologist to monitor their progress. If the defect is very complex, or the heart becomes weak after the surgeries, a heart transplant may be needed.

Infants who receive a heart transplant will need to take medicines for the rest of their lives to prevent their body from rejecting the new heart.

REFERENCES: SLIDE 03,18: http://ghr.nlm.nih.gov/condition/critical-congenital-heart-disease SLIDE 05-09: http://www.cdc.gov/ncbddd/heartdefects/data.html SLIDE 10-12: http://www.cdc.gov/ncbddd/heartdefects/cchd-facts.html SLIDE 13-16: http://www.cdc.gov/ncbddd/heartdefects/hcp.html SLIDE 17: http://ghr.nlm.nih.gov/condition/critical-congenital-heart-disease SLIDE 18-21: http://www.cdc.gov/ncbddd/heartdefects/hlhs.html SLIDE 22-26: http://www.cdc.gov/ncbddd/heartdefects/pulmonaryatresia.html SLIDE 27-29: http://www.cdc.gov/ncbddd/heartdefects/tetralogyoffallot.html SLIDE 30-33: http://www.cdc.gov/ncbddd/heartdefects/tapvr.html SLIDE 34-37: http://www.cdc.gov/ncbddd/heartdefects/d-tga.html SLIDE 38-41: http://www.cdc.gov/ncbddd/heartdefects/tricuspid-atresia.html SLIDE 42-44: http://www.cdc.gov/ncbddd/heartdefects/truncusarteriosus.html SLIDE 20,21,25,28,29,34,37,38,41,42,45 (Some data): http://

www.utmb.edu/pedi_ed/CORE/Cardiology