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Congenital Heart Disease

Disease Details

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Description: Congenital heart disease refers to a range of structural heart defects present from birth that can affect the flow of blood through the heart and to the rest of the body.
Type: Congenital heart disease is a broad term for a range of heart abnormalities present at birth. The type of genetic transmission can vary depending on the specific condition but generally includes multifactorial inheritance (a combination of genetic and environmental factors), autosomal dominant inheritance, and autosomal recessive inheritance. Some forms are also associated with chromosomal abnormalities such as Down syndrome (trisomy 21).
Signs And Symptoms: Signs and symptoms are related to type and severity of the heart defect. Symptoms frequently present early in life, but it is possible for some CHDs to go undetected throughout life. Some children have no signs while others may exhibit shortness of breath, cyanosis, fainting, heart murmur, under-development of limbs and muscles, poor feeding or growth, or respiratory infections. Congenital heart defects cause abnormal heart structure resulting in production of certain sounds called heart murmur. These can sometimes be detected by auscultation; however, not all heart murmurs are caused by congenital heart defects.
Prognosis: The prognosis for congenital heart disease (CHD) varies widely depending on the type and severity of the defect, as well as the treatment received. Advances in medical and surgical care have significantly improved outcomes for many individuals with CHD. Some individuals may live normal or near-normal lives with appropriate medical management and regular follow-up, while others may experience complications requiring ongoing treatment and interventions. Early detection and individualized care plans are crucial for optimizing long-term outcomes.
Onset: Congenital heart disease (CHD) is present at birth. It encompasses a variety of heart defects that develop during fetal growth.
Prevalence: The prevalence of congenital heart disease (CHD) varies globally but is commonly estimated to affect approximately 1% of live births. This means that out of every 1,000 live births, about 8-12 babies are likely to be born with some form of CHD.
Epidemiology: Heart defects are among the most common birth defect, occurring in 1% of live births (2–3% including bicuspid aortic valve). In 2013, 34.3 million people had CHD. In 2010, they resulted in 223,000 deaths, down from 278,000 deaths in 1990.For congenital heart defects that arise without a family history (de novo), the recurrence risk in offspring is 3–5%. This risk is higher in left ventricular outflow tract obstructions, heterotaxy, and atrioventricular septal defects.
Intractability: Congenital heart disease is not uniformly intractable. While its complexity varies widely, many forms of congenital heart defects can be effectively managed or corrected with medical intervention, including surgeries, medications, and lifestyle changes. Advances in medical technology and treatment have significantly improved outcomes for many individuals. However, severe cases may present ongoing challenges and require continued care.
Disease Severity: Congenital heart disease (CHD) severity can vary widely depending on the specific type and complexity of the defect present. Some cases might involve minor defects that cause few or no symptoms, while others can be life-threatening and require immediate medical intervention.

There is no single scale for congenital heart disease severity; it often ranges from mild to severe:

1. **Mild**: Small defects that might not need treatment or only minor intervention, such as small septal defects.
2. **Moderate**: Defects that do require medical or surgical intervention but can be effectively managed, such as moderate valve abnormalities.
3. **Severe**: Complex conditions involving multiple defects that typically require multiple surgical procedures or long-term medical care, such as Hypoplastic Left Heart Syndrome or Tetralogy of Fallot.

Severity often determines the course of treatment, prognosis, and the level of monitoring required throughout the patient's life.
Healthcare Professionals: Disease Ontology ID - DOID:1682
Pathophysiology: Congenital heart disease (CHD) encompasses a variety of structural abnormalities of the heart and great vessels present at birth. The pathophysiology of CHD differs based on the specific type of defect, but it generally involves issues with the formation and separation of the heart chambers, valves, and arteries during fetal development.

Key points include:

1. **Obstructive Lesions**: These involve blockages or narrowing in blood flow, such as pulmonary stenosis, aortic stenosis, or coarctation of the aorta. This can lead to increased pressure in certain chambers of the heart and compensatory hypertrophy.

2. **Shunt Lesions**: These defects result in abnormal blood flow between the heart’s chambers or great vessels due to septal defects (e.g., atrial septal defect, ventricular septal defect) or patent ductus arteriosus. Depending on the pressure gradients, blood can flow from the left side to the right side of the heart (left-to-right shunt) or from right to left (right-to-left shunt), affecting oxygenation efficiency.

3. **Complex Cyanotic Lesions**: These severe forms involve both shunting and obstruction and lead to cyanosis. Examples include Tetralogy of Fallot, transposition of the great arteries, and truncus arteriosus. These conditions typically result in significant reductions in oxygenated blood being circulated, leading to cyanosis and other complications.

4. **Valvular Abnormalities**: Defects in the heart valves can lead to regurgitation or stenosis, impacting blood flow and increasing cardiac workload.

The specific molecular and genetic mechanisms can include mutations in critical genes responsible for heart development, environmental factors, or a combination of both. The abnormal heart structure alters normal hemodynamics, impacting systemic and pulmonary circulation, which might result in symptoms such as cyanosis, heart failure, growth retardation, or arrhythmias, depending on the severity and type of defect.
Carrier Status: Congenital heart disease is not typically associated with a carrier status, as it is a structural defect in the heart present at birth and not usually inherited in a simple Mendelian fashion. Some forms can be linked to genetic conditions which might have carrier states, but this depends on the specific syndrome or genetic mutation involved.
Mechanism: There is a complex sequence of events that result in a well formed heart at birth and disruption of any portion may result in a defect. The orderly timing of cell growth, cell migration, and programmed cell death ("apoptosis") has been studied extensively and the genes that control the process are being elucidated.
Around day 15 of development, the cells that will become the heart exist in two horseshoe shaped bands of the middle tissue layer (mesoderm), and some cells migrate from a portion of the outer layer (ectoderm), the neural crest, which is the source of a variety of cells found throughout the body. On day 19 of development, a pair of vascular elements, the "endocardial tubes", form. The tubes fuse when cells between then undergo programmed death and cells from the first heart field migrate to the tube, and form a ring of heart cells (myocytes) around it by day 21. On day 22, the heart begins to beat and by day 24, blood is circulating.At day 22, the circulatory system is bilaterally symmetrical with paired vessels on each side and the heart consisting of a simple tube located in the midline of the body layout. The portions that will become the atria and will be located closest to the head are the most distant from the head. From days 23 through 28, the heart tube folds and twists, with the future ventricles moving left of center (the ultimate location of the heart) and the atria moving towards the head.On day 28, areas of tissue in the heart tube begin to expand inwards; after about two weeks, these expansions, the membranous "septum primum" and the muscular "endocardial cushions", fuse to form the four chambers of the heart. A failure to fuse properly will result in a defect that may allow blood to leak between chambers. After this happens, cells that have migrated from the neural crest begin to divide the bulbus cordis, the main outflow tract is divided in two by the growth a spiraling septum, becoming the great vessels—the ascending segment of the aorta and the pulmonary trunk. If the separation is incomplete, the result is a "persistent truncus arteriosus". The vessels may be reversed ("transposition of the great vessels"). The two halves of the split tract must migrate into the correct positions over the appropriate ventricles. A failure may result in some blood flowing into the wrong vessel (e.g.overriding aorta). The four-chambered heart and the great vessels have features required for fetal growth. The lungs are unexpanded and cannot accommodate the full circulatory volume. Two structures exist to shunt blood flow away from the lungs. Cells in part of the septum primum die creating a hole while muscle cells, the "septum secundum", grow along the right atrial side the septum primum, except for one region, leaving a gap through which blood can pass from the right artium to the left atrium, the foramen ovale. A small vessel, the ductus arteriosus allows blood from the pulmonary artery to pass to the aorta.
Treatment: CHD may require surgery and medications. Medications include diuretics, which aid the body in eliminating water, salts, and digoxin for strengthening the contraction of the heart. This slows the heartbeat and removes some fluid from tissues. Some defects require surgical procedures to restore circulation back to normal and in some cases, multiple surgeries are needed.Interventional cardiology now offers minimally invasive alternatives to surgery for some patients. The Melody Transcatheter Pulmonary Valve (TPV), approved in Europe in 2006 and in the U.S. in 2010 under a Humanitarian Device Exemption (HDE), is designed to treat congenital heart disease patients with a dysfunctional conduit in their right ventricular outflow tract (RVOT). The RVOT is the connection between the heart and lungs; once blood reaches the lungs, it is enriched with oxygen before being pumped to the rest of the body. Transcatheter pulmonary valve technology provides a less-invasive means to extend the life of a failed RVOT conduit and is designed to allow physicians to deliver a replacement pulmonary valve via a catheter through the patient's blood vessels.Many people require lifelong specialized cardiac care, first with a pediatric cardiologist and later with an adult congenital cardiologist. There are more than 1.8 million adults living with congenital heart defects.
Compassionate Use Treatment: For congenital heart disease (CHD), compassionate use and off-label or experimental treatments may be considered in specific circumstances. These treatments are generally considered when conventional therapies are inadequate or unavailable. Here are some examples:

1. **Compassionate Use Treatment:**
- **Medication:** Certain medications not yet approved for CHD but showing promise in clinical trials may be available under compassionate use protocols.
- **Devices:** Experimental cardiac devices, such as novel types of stents or valves, might be accessible through compassionate use to improve heart function or correct structural anomalies.

2. **Off-label Treatments:**
- **Medications:** Drugs approved for other cardiovascular conditions but used off-label in CHD patients, such as sildenafil (originally for erectile dysfunction but sometimes used for pulmonary hypertension in CHD).
- **Beta-blockers and ACE inhibitors:** Though primarily used for hypertension and heart failure, they may be prescribed off-label to manage symptoms or complications related to CHD.

3. **Experimental Treatments:**
- **Stem Cell Therapy:** Investigational use of stem cell therapy to repair damaged heart tissue and improve heart function in CHD patients.
- **Gene Therapy:** Experimental approaches attempting to correct genetic defects responsible for certain types of CHD.

These options are typically considered as part of a clinical trial or under specific regulatory permissions to ensure patient safety and effectiveness. Always consult with a specialized cardiologist to explore these options.
Lifestyle Recommendations: For individuals with congenital heart disease, lifestyle recommendations typically include:

1. **Regular Medical Follow-ups**: Maintain consistent check-ups with a cardiologist to monitor heart health and manage any complications.
2. **Physical Activity**: Engage in appropriate exercise as recommended by a healthcare provider. Some may need tailored exercise plans to avoid excessive strain on the heart.
3. **Healthy Diet**: Follow a heart-healthy diet rich in vegetables, fruits, whole grains, and lean proteins. Limit saturated fats, trans fats, cholesterol, and sodium.
4. **Avoid Tobacco**: Do not smoke or use tobacco products, as they can exacerbate heart issues.
5. **Moderate Alcohol Intake**: If allowed by a healthcare provider, consume alcohol in moderation.
6. **Dental Hygiene**: Maintain good dental hygiene and regular dental check-ups to prevent infections that could affect the heart.
7. **Stress Management**: Employ techniques such as meditation, yoga, or other relaxation methods to reduce stress levels.
8. **Medication Adherence**: Follow prescribed medication regimens strictly to control symptoms and prevent complications.
9. **Awareness of Symptoms**: Be vigilant about recognizing and promptly addressing any new or worsening symptoms.

These recommendations should be individualized based on the specific type and severity of congenital heart disease, alongside professional medical advice.
Medication: There is a variety of medications used to manage symptoms and complications of congenital heart disease, which can vary depending on the specific condition and severity. Common medications may include:

- **Diuretics:** Help reduce excess fluid in the body and decrease the workload on the heart.
- **Beta-blockers:** Manage abnormal heart rhythms and decrease blood pressure.
- **ACE inhibitors:** Relax blood vessels and lower blood pressure, improving heart function.
- **Anticoagulants/Antiplatelets:** Prevent blood clots that can lead to stroke or other complications.
- **Digoxin:** Strengthens heart muscle contractions and helps regulate heart rhythms.

The exact medication regimen must be tailored to the individual by a healthcare professional.
Repurposable Drugs: Drug repurposing involves finding new therapeutic uses for existing medications. For congenital heart disease (CHD), certain drugs originally approved for other cardiovascular conditions may be considered for repurposing:

1. **Sildenafil** - Originally used for erectile dysfunction and pulmonary hypertension, it can improve exercise capacity and hemodynamics in patients with CHD-associated pulmonary arterial hypertension.
2. **Bosentan** - This endothelin receptor antagonist, initially developed for pulmonary arterial hypertension, can benefit CHD patients with associated pulmonary hypertension.
3. **Beta-blockers (Propranolol)** - Often used for arrhythmias, they can help manage specific arrhythmias in CHD patients.
4. **ACE inhibitors (e.g., Enalapril)** - Commonly used for hypertension and heart failure, they may benefit CHD patients by reducing cardiac workload and improving heart function.

It is essential to consult healthcare professionals for personalized medical advice before considering any repurposed drugs.
Metabolites: For congenital heart disease, no specific metabolites are universally associated as biomarkers for the diagnosis across all forms of the condition. However, some studies have suggested that certain metabolic changes, such as alterations in amino acids, lipids, and energy metabolism pathways, might be indicative of the disease. Further research is ongoing to better understand these metabolic profiles and their potential diagnostic or therapeutic applications.
Nutraceuticals: There is limited evidence on the efficacy of nutraceuticals in managing or treating congenital heart disease (CHD). Nutraceuticals, which include dietary supplements, functional foods, and herbal products, are sometimes considered for their potential benefits on overall cardiovascular health. However, they should not replace standard medical treatments. Always consult with a healthcare professional before starting any new supplement regimen for managing CHD.
Peptides: Congenital heart disease (CHD) refers to a range of structural abnormalities of the heart present at birth. Peptides and nanoparticles (nan) are emerging as potential therapeutic and diagnostic tools for congenital heart disease. Peptides can be used for targeted drug delivery, tissue repair, and regeneration. Nanoparticles, on the other hand, offer potential in imaging, targeted therapy, and even gene editing, providing less invasive and more effective treatment options. Research in these areas is ongoing to enhance the management and outcomes of CHD.