CONGENITAL HEART DISEASES
Nurse Dyrionyema Munachiso Victoria
DEFINITION
Congenital heart disease(CHD) is a general term for a range of birth defects that affect the normal way the heart works. They can affect how blood flows through the heart and out to the rest of the body. CHDs can vary from mild (such as a small hole in the heart) to severe (such as missing or poorly formed parts of the heart). It can be detected before birth, soon after birth or anytime throughout life. There are many kinds of CHD.
THE HEART
The human heart is a muscular organ, around the size of a closed fist that sits in the chest, slightly to the left. The heart consists of four chambers:
The atria: These are the two upper chambers, which receive blood.
The ventricles: These are the two lower chambers, which discharge blood.
A wall of tissue called the septum separates the left and right atria and the left and right ventricle. Four valves separate the atria from the ventricles to ensure that blood only flows in one direction:
Aortic valve: This is between the left ventricle and the aorta.
Mitral valve: This is between the left atrium and the left ventricle.
Pulmonary valve: This is between the right ventricle and the pulmonary artery.
Tricuspid valve: This is between the right atrium and right ventricle.
CAUSES
CHD happens when the fetal heart doesn’t develop correctly in the uterus. This may be related to:
Abnormal chromosomes or genetics.
Drinking or smoking during pregnancy (or significant environmental exposures such as secondhand smoke).
Illnesses in the mother during pregnancy (diabetes, or viral infection).
Certain medications such as anti-seizure medicines (such as benzodiazepines) or certain acne medicines(such as isotretinoin and topical retinoids)
SYMPTOMS
A congenital heart defect is often detected during a pregnancy ultrasound. In some cases, the symptoms may not appear until shortly after birth. Newborns may experience:
Breathlessness or trouble breathing
Feeding difficulties
Low birth weight
Chest pain
Delayed growth
Bluish lips, skin, fingers, and toes
In other cases, the symptoms of a congenital heart defect may not appear until many years after birth. Once symptoms do develop, they may include:
Abnormal heart rhythms
Dizziness
Trouble breathing
Fainting
Swelling
Fatigue
TYPES
Aortic valve stenosis
In aortic valve stenosis, the aortic valve that controls the flow of blood out of the left ventricle to the aorta is narrowed. This affects the flow of oxygen-rich blood away from the heart, towards the rest of the body, and may result in the left ventricle muscle thickening because the pump has to work harder.
Coarctation of the aorta
Coarctation of the aorta (CoA) is where the aorta has a narrowing, which means that less blood can flow through it. CoA can occur by itself or in combination with other types of heart defects, such as a ventricular septal defect or a type of defect known as a patent ductus arteriosus. The narrowing can be severe and will often require treatment shortly after birth.
Patent ductus arteriosus
As a baby develops in the womb, a blood vessel called the ductus arteriosus connects the pulmonary artery directly to the aorta. The ductus arteriosus diverts blood away from the lung (which isn't working normally before birth) to the aorta. A patent ductus arteriosus is where this connection doesn't close after birth as it's supposed to. This means that extra blood is pumped into the lungs, forcing the heart and lungs to work harder.
Pulmonary valve stenosis
Pulmonary valve stenosis is a defect where the pulmonary valve, which controls the flow of blood out of the right ventricle to the lungs, is narrower than normal. This means the right ventricle has to work harder to push blood through the narrowed valve to get to the lungs.
Septal defects
A septal defect is where there's an abnormality in the wall (septum) between the main chambers of the heart. There are 2 main types of septal defect.
Atrial septal defects
An atrial septal defect (ASD) is where there's a hole between the 2 collecting chambers of the heart (the left and right atria). When there's an ASD, extra blood flows through the defect into the right side of the heart, causing it to stretch and enlarge.
Ventricular septal defects
A ventricular septal defect (VSD) is a common form of congenital heart disease. It occurs when there's a hole between the 2 pumping chambers of the heart (the left and right ventricles). This means that extra blood flows through the hole from the left to the right ventricle, due to the pressure difference between them. The extra blood goes to the lungs, causing high pressure in the lungs and a stretch on the left ventricle. Small holes often eventually close by themselves, but larger holes need to be closed using surgery.
Single ventricle defects
A single ventricle defect is where only 1 of the ventricles develops properly. Without treatment, these defects can be fatal within a few weeks of birth. However, nowadays complex heart operations can be carried out which improve longer-term survival but may leave a person with symptoms and a shortened life span.
Tetralogy of Fallot
Tetralogy of Fallot is a rare combination of several defects. The defects making up tetralogy of Fallot are:
Ventricular septal defect – a hole between the left and right ventricle
Pulmonary valve stenosis – narrowing of the pulmonary valve
Right ventricular hypertrophy – where the muscle of the right ventricle is thickened
Overriding aorta – where the aorta isn't in its usual position coming out of the heart
As a result of this combination of defects, oxygenated and non-oxygenated blood mixes, causing the overall amount of oxygen in the blood to be lower than normal. This may cause the baby to appear blue (known as cyanosis) at times.
DIAGNOSIS
Diagnosis during pregnancy
Congenital heart disease may initially be suspected during a routine ultrasound scan of the baby in the womb. Specialist ultrasound, called foetal echocardiography, will then be carried out at around 18 to 22 weeks of the pregnancy to try to confirm the exact diagnosis.
Diagnosis after birth
It's sometimes possible to diagnose a baby with congenital heart disease shortly after birth if some of the characteristic signs or symptoms of congenital heart disease, such as a blue tinge to the skin or lips (cyanosis), are present. However, some defects don't cause any noticeable symptoms for several months or even years. Further testing can usually help to confirm or rule out a diagnosis.
Echocardiography
An echocardiogram is often used to check the inside of the heart. Heart problems that were missed during foetal echocardiography can sometimes be detected as a child develops.
Chest X-ray
A chest X-ray of the heart and lungs can be used to check whether there's an excess amount of blood in the lungs, or whether the heart is larger than normal. Both may be signs of heart disease.
Pulse oximetry
Pulse oximetry is a test that measures the amount of oxygen present in the blood. The test involves placing a special sensor on the fingertip, ear or toe that sends out light waves. A computer is connected to the sensor and measures how the light waves are absorbed. Oxygen can affect how the light waves are absorbed, so by analysing the results, the computer can quickly determine how much oxygen is present in the blood.
Cardiac catheterisation
Cardiac catheterisation is a useful way of obtaining more information about exactly how the blood is being pumped through the heart. During the procedure, a small, flexible tube called a catheter is inserted into a blood vessel, usually through an artery and/or vein in the groin, neck or arm. The catheter is moved into the heart, guided by X-rays or sometimes an MRI scanner, and allows pressure measurements in different parts of the heart or lungs to be taken.
PREVENTION
As so little is known about the causes of congenital heart disease, there's no guaranteed way of avoiding having a baby with the condition. However, if one is pregnant, the following advice can help reduce the risk:
Ensure you are vaccinated against rubella and flu.
Avoid drinking alcohol
Take 400 micrograms of folic acid supplement a day during the first trimester (first 12 weeks)– this lowers your risk of giving birth to a child with congenital heart disease, as well as several other types of birth defect.
Check with your doctor before taking any medicine during pregnancy, including herbal remedies and medicine that's available over the counter.
Avoid contact with people who are known to have an infection.
If you have diabetes, make sure it's controlled.
TREATMENT
The treatment for a congenital heart defect depends on the type and severity of the defect. Some babies have mild heart defects that heal on their own with time. Others may have severe defects that require extensive treatment. In these cases, treatment may include the following:
Medications
There are various medications that can help the heart work more efficiently. Some can also be used to prevent blood clots from forming or to control an irregular heartbeat.
Implantable Heart Devices
Some of the complications associated with congenital heart defects can be prevented with the use of certain devices, including pacemakers and implantable cardioverter defibrillators (ICDs). A pacemaker can help regulate an abnormal heart rate, and an ICD may correct life-threatening irregular heartbeats.
Catheter Procedures
Catheterization techniques allow doctors to repair certain congenital heart defects without surgically opening the chest and heart. During these procedures, the doctor will insert a thin tube into a vein in the leg and guide it up to the heart. Once the catheter is in the correct position, the doctor will use small tools threaded through the catheter to correct the defect.
Open-Heart Surgery
This type of surgery may be needed if catheter procedures aren’t enough to repair a congenital heart defect. A surgeon may perform open-heart surgery to close holes in the heart, repair heart valves, or widen blood vessels.
Heart Transplant
In the rare cases in which a congenital heart defect is too complex to fix, a heart transplant may be needed. During this procedure, the child’s heart is replaced with a healthy heart from a donor.
CONGENITAL HEART DISEASE IN ADULTS
Depending on the defect, diagnosis and treatment may begin shortly after birth, during childhood, or in adulthood. Some defects don’t cause any symptoms until the child becomes an adult, so diagnosis and treatment may be delayed. The treatment for congenital heart disease in adults can also vary depending on the severity of the heart defect.
In some cases, defects that may have been treated in childhood can present problems again in adulthood. The original repair may no longer be effective or the initial defect may have become worse over time. Scar tissue that developed around the original repair may also end up causing problems, such as heart arrhythmias.
Regardless of the situation, it’s important for one to continue seeing his/her doctor for follow-up care. Treatment may not cure the condition, but it can help maintain an active, productive life. It will also reduce ones risk for serious complications, such as heart infections, heart failure, and stroke.
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