Congenital Heart Disease

Congenital heart disease (CHD) encompasses various structural problems with the heart that are present at birth. These abnormalities arise when the heart or blood vessels fail to form correctly during foetal development, which can affect the normal functioning of the heart. In this article, we will explore the different aspects of congenital heart disease, including its causes, symptoms, types, and treatment options.

What is Congenital Heart Disease?

Congenital heart disease (CHD) refers to a group of heart defects that are present at birth. These defects occur when the heart or blood vessels near the heart do not develop normally during foetal development. CHD can affect various parts of the heart, such as the heart walls (septum), valves, or blood vessels, leading to disrupted blood flow and potential complications. The severity of CHD can range from minor defects that may not require treatment to complex conditions that necessitate immediate medical intervention. While some congenital heart defects may be detected during pregnancy or shortly after birth, others may not be diagnosed until adulthood.

There are several types of congenital heart diseases, each with varying degrees of severity and impact on the circulatory system. Here are some of the common types:

• Aortic valve stenosis (AVS): This condition involves the narrowing of the aortic valve, which controls the flow of blood from the heart to the rest of the body. AVS can lead to reduced blood flow and increased strain on the heart.

• Coarctation of the aorta (CoA): This defect involves the narrowing of the aorta, the main artery that carries blood from the heart to the rest of the body. CoA can cause high blood pressure in the upper body and reduced blood flow to the lower body.

• Ebstein's anomaly: This congenital heart defect involves the abnormal formation of the tricuspid valve and the right ventricle, leading to inadequate blood flow to the lungs. Symptoms may include cyanosis (bluish discolouration of the skin), fatigue, and shortness of breath.

• Patent ductus arteriosus (PDA): This condition occurs when the ductus arteriosus, a blood vessel that connects the aorta and pulmonary artery in the foetus, fails to close after birth, leading to excessive blood flow to the lungs. PDA can cause heart failure and pulmonary hypertension if left untreated.

• Pulmonary valve stenosis: This condition involves the narrowing of the pulmonary valve, which controls the flow of blood from the heart to the lungs. Pulmonary valve stenosis can cause reduced blood flow to the lungs and increased strain on the right ventricle.

• Septal defects: These defects involve holes in the septum, the wall of tissue that separates the heart's chambers, leading to abnormal blood flow between the chambers. The most common types are atrial septal defect (ASD) and ventricular septal defect (VSD).

• Single ventricle defects: These defects involve the underdevelopment of one of the heart's ventricles, leading to inadequate blood flow to the lungs and the rest of the body. Examples include hypoplastic left heart syndrome (HLHS) and tricuspid atresia.

• Tetralogy of fallot: This congenital heart defect involves four components: a ventricular septal defect, pulmonary stenosis, right ventricular hypertrophy, and an overriding aorta. Symptoms may include cyanosis, shortness of breath, and fainting.

• Total (or partial) anomalous pulmonary venous connection (TAPVC): This condition occurs when the pulmonary veins, which carry oxygenated blood from the lungs to the heart, are connected to the right atrium instead of the left atrium. TAPVC can lead to the mixing of oxygenated and deoxygenated blood, causing cyanosis and heart failure.

The symptoms of congenital heart disease can manifest differently depending on the type and severity of the defect. Some common signs and symptoms to look out for include:

• Irregular heartbeats (arrhythmias): Abnormal heart rhythms that can be detected through an electrocardiogram (ECG).

• Cyanosis: A bluish or greyish discolouration of the skin, lips, and fingernails due to low oxygen levels in the blood, particularly noticeable in cyanotic CHD.

• Shortness of breath: Difficulty breathing, especially during feeding in infants, which can lead to poor weight gain.

• Fatigue: Easily getting tired during physical activity or exercise, more commonly observed in older children and adults with CHD.

• Swelling (oedema): Accumulation of fluid in body tissues, causing swelling in the legs, abdomen, or areas around the eyes.

Congestive heart failure progresses through four stages (A, B, C, and D), from high-risk to advanced heart failure. These include:

• Stage A: Individuals are at high risk for developing heart failure but show no symptoms. Risk factors include hypertension, diabetes, coronary artery disease, metabolic syndrome, alcohol use disorder, a history of rheumatic fever, and exposure to certain cardiotoxic medications (such as doxorubicin).

• Stage B: The left ventricle is structurally abnormal or not functioning well, but the individual has not yet experienced symptoms of heart failure.

• Stage C: Patients are diagnosed with congestive heart failure and currently show or have previously had symptoms such as fatigue and shortness of breath.

• Stage D: This final stage involves advanced heart failure with reduced ejection fraction (HFrEF), where severe symptoms persist despite treatment, requiring intensive management.

The various factors that can increase the likelihood of developing CHD include:

• Genetic factors: A family history of heart defects may indicate a genetic predisposition. Certain genetic syndromes, such as Down syndrome, are associated with a higher incidence of congenital heart disease.

• Maternal health conditions: Preexisting medical conditions in the mother, such as diabetes, lupus, or phenylketonuria (PKU), can increase the likelihood of CHD in the baby.

• Maternal infections: Exposure to certain viral infections like rubella (German measles) during pregnancy can affect heart development in the foetus.

• Medications and substances: The use of certain medications (such as valproate, carbamazepine and isotretinoin) and alcohol during pregnancy may disrupt normal heart formation.

• Environmental factors: Exposure to chemicals or radiation during critical periods of foetal development can potentially contribute to the development of CHD.

Several risk factors can increase the likelihood of a baby being born with congenital heart disease (CHD), including:

• Maternal diabetes, particularly type 1 and type 2 diabetes

• Genetic conditions such as Down syndrome, Turner syndrome, and Noonan syndrome

• Rubella infection during pregnancy, especially during the first trimester

• Consumption of alcohol and smoking during pregnancy

• Certain medications taken during pregnancy, such as lithium and isotretinoin

• Antenatal febrile illness

• Advanced maternal and paternal age

• Previous complications during pregnancy or a history of stillbirths/abortions

Congenital heart disease can lead to various complications that may have a lasting impact on a child's health and development. Some of the most common complications include:

• Congestive heart failure: Severe congenital heart defects can cause the heart to work harder, leading to congestive heart failure. Symptoms may include rapid breathing, poor weight gain, and fatigue.

• Endocarditis: Children with CHD are at a higher risk of developing endocarditis, an infection of the heart lining and valves. This condition can be life-threatening if not treated promptly with antibiotics.

• Pulmonary hypertension: Some congenital heart defects can cause increased blood flow to the lungs, leading to pulmonary hypertension. This condition can cause shortness of breath, fatigue, and chest pain.

• Arrhythmias: Abnormal heart rhythms, or arrhythmias, can occur in children with CHD due to the structural changes in the heart.

• Developmental delays: Children with congenital heart disease may experience developmental delays in areas such as growth, motor skills, and cognitive function.

• Neurodevelopmental disorders: Some children with CHD may be at a higher risk for neurodevelopmental disorders, such as attention deficit hyperactivity disorder (ADHD) or learning disabilities.

While not all cases of congenital heart disease can be prevented, there are several steps that prospective parents can take to reduce the risk of their child developing a congenital heart defect. These include:

• Preconception care: Women planning to become pregnant should consult with their doctor to discuss any pre-existing health conditions, such as diabetes, and ensure that they are well-controlled before conception.

• Prenatal vitamins: Taking prenatal vitamins containing folic acid before and during pregnancy can help reduce the risk of certain congenital heart defects, as well as other birth defects like spina bifida.

• Avoid teratogens: Pregnant women should avoid exposure to known teratogens, such as alcohol, tobacco, and certain medications, which can increase the risk of congenital heart defects and other birth defects.

• Manage chronic conditions: Women with chronic health conditions, such as diabetes or hypertension, should work closely with their doctor to manage these conditions throughout pregnancy, as poorly controlled chronic diseases can increase the risk of CHD.

• Prenatal screening: Regular prenatal check-ups and screenings, such as ultrasounds and foetal echocardiography, can help detect congenital heart defects early in pregnancy, allowing for better preparation and management of the condition.

• Genetic counselling: Families with a history of congenital heart disease or other genetic disorders may benefit from genetic counselling to understand their risk and make informed decisions about family planning.

Diagnosing congenital heart disease involves a combination of physical examinations, imaging studies, and other diagnostic tests. The following are some of the most common methods used to diagnose CHD:

• Physical examination: A thorough physical examination, including listening to the heart and lungs, can help detect signs of congenital heart disease, such as a heart murmur or abnormal pulse.

• Pulse oximetry screening: This non-invasive test measures the oxygen saturation in a newborn's blood and can help identify some critical congenital heart defects that may not be apparent during a physical examination.

• Echocardiogram: An echocardiogram is an ultrasound of the heart that allows healthcare professionals to visualise the heart's structure and function. This test can help diagnose most congenital heart defects and guide treatment decisions.

• Electrocardiogram (ECG): An ECG records the heart's electrical activity and can help detect abnormal heart rhythms or other signs of congenital heart disease.

• Chest X-ray: A chest X-ray can show the heart's size and shape and help identify any changes in the lungs that may be related to congenital heart disease.

• Cardiac catheterization: In some cases, a thin tube called a catheter may be inserted into the heart through a blood vessel to measure pressure and oxygen levels and to visualise the heart's structure more clearly.

• Magnetic resonance imaging (MRI): Cardiac MRI can provide detailed images of the heart and surrounding blood vessels, helping to diagnose complex congenital heart defects.

The treatment for congenital heart disease varies based on the type and severity of the defect, as well as the patient’s overall health. Some of the options include:

• Medications: Medications for congenital heart disease include diuretics (e.g., furosemide) to reduce fluid buildup, beta-blockers (e.g., metoprolol) to manage heart rate, and anticoagulants (e.g., warfarin, aspirin) to prevent blood clots.

• Surgery: Surgical intervention for significant congenital heart defects ranges from simple repairs to complex procedures, addressing issues like septal defects and narrowed blood vessels. This includes reconstructive surgery for conditions such as tetralogy of Fallot or transposition of the great arteries.

• Catheter-based procedures: Less invasive than traditional surgery, catheter-based interventions can be performed to treat certain defects. Techniques may include balloon angioplasty to widen narrowed vessels and the use of closure devices to seal holes in the heart.

• Heart transplant: In severe cases where other treatments are ineffective, heart transplantation may be considered, particularly for individuals with end-stage heart failure due to congenital defects.

Living with congenital heart disease involves several key considerations, including:

• Adults with congenital heart disease need lifelong follow-up care with a cardiologist trained in treating adults with these conditions.

• Patients should be aware of the signs and symptoms of congenital heart defects to watch for and know when to contact their healthcare team.

• Participating in cardiac rehabilitation programs can help regain strength and reduce the risk of future heart problems.

• Taking antibiotics before dental work or surgery can prevent endocarditis, a serious infection of the heart's inner lining.

• Staying up-to-date on flu and pneumonia vaccinations is crucial for individuals with congenital heart disease.

If you or your child experiences any signs or symptoms of congenital heart disease, it is essential to consult a doctor promptly. Some common symptoms that warrant medical attention include:

• Shortness of breath, especially during physical activity or at rest

• Fatigue or tiring easily during physical activity

• Swelling in the ankles, feet, or abdomen

• Heart palpitations or irregular heartbeats

• Chest pain or discomfort

• Fainting or dizziness

• Bluish discolouration of the skin, lips, or fingernails (cyanosis)

In some cases, congenital heart defects may not cause noticeable symptoms until adulthood. Adults who have been diagnosed with a congenital heart defect should maintain regular check-ups with a cardiologist specialising in adult congenital heart disease to monitor their condition and address any potential complications.

• Congenital heart disease refers to a range of heart defects present at birth, affecting the heart's structure and function.

• Common types of congenital heart defects include ventricular septal defect, atrial septal defect, tetralogy of Fallot, and patent ductus arteriosus.

• Symptoms of congenital heart disease may include shortness of breath, fatigue, swelling, heart palpitations, chest pain, fainting, and cyanosis.

• Treatment for congenital heart disease depends on the type and severity of the defect and may include medications, surgical interventions, catheter-based procedures, or lifestyle modifications.

• Regular monitoring, symptom awareness, cardiac rehabilitation, infection prevention, and staying up-to-date on vaccinations are essential for individuals living with congenital heart disease.

• If you or your child experiences symptoms of congenital heart disease, consult a doctor promptly for proper diagnosis and treatment.