Congenital heart disease is a general term for a problem with the structure of the heart or its major blood vessels that is present at birth. “Congenital” simply means existing from birth. There are many different types of CHDs, ranging from simple defects that may cause no problems to complex, life-threatening conditions that require immediate surgical intervention.

To understand what can go wrong, it is helpful to first picture a normal heart.

• A helpful analogy is to think of the heart as a sophisticated, two-sided, four-room house with a complex plumbing system designed to move blood.
  • The right side of the house (the right atrium and ventricle) receives “blue,” oxygen-poor blood from the body and pumps it only to the “oxygen-refilling station” (the lungs).
  • The left side of the house (the left atrium and ventricle) receives the fresh, “red,” oxygen-rich blood back from the lungs and pumps it out to the rest of the neighborhood (the body).
  • Valves act as perfect one-way doors between the rooms, and walls (septums) keep the blue and red blood completely separate.

A congenital heart defect is a problem with the house’s original construction blueprint. The error can occur in many different ways:

• Holes in the Walls: There can be a hole in the wall between the two upper rooms (an atrial septal defect, or ASD) or between the two lower rooms (a ventricular septal defect, or VSD), allowing blue and red blood to mix.
• Narrowed Doorways: A valve can be too narrow, stiff, or malformed (stenosis), making it hard for the heart to pump blood through it.
• Leaky Doorways: A valve may not close properly, allowing blood to leak backward (regurgitation).
• Faulty Plumbing: The main arteries leaving the heart can be switched (transposition of the great arteries), connected to the wrong rooms, or be completely missing.
• Underdeveloped Rooms: One of the main pumping chambers (a ventricle) may be critically underdeveloped (hypoplastic heart syndrome).

These defects are often categorized by whether they cause cyanosi, a bluish tint to the skin from a lack of oxygen.

• Acyanotic defects (like a simple VSD) do not typically cause cyanosis.
• Cyanotic defects (like Tetralogy of Fallot or transposition) cause blue blood to be pumped to the body, resulting in cyanosis.

In my experience, many parents are overwhelmed when they first hear their newborn has a heart defect but understanding that CHD varies widely in severity helps guide care and expectations.

The heart is one of the first organs to form during fetal development, undergoing a complex process of folding and dividing between the third and eighth weeks of pregnancy. CHD is caused by an error during this critical period of heart development.

In most cases, the exact cause is unknown. It is believed to be a multifactorial process, meaning it results from a complex interplay of genetic factors and potential environmental exposures. It is almost never the result of anything the parents did or did not do.

In my experience, most cases are idiopathic. No clear cause is identified but a family history of CHD does increase the risk.

A baby is born with CHD due to an error that occurred while their heart was forming in the womb. It is not contagious.

The primary risk factors include:

• Genetic and Chromosomal Syndromes: While most CHD is not part of a broader syndrome, it can be a feature of certain genetic conditions, such as Down syndrome (Trisomy 21), 22q11.2 deletion syndrome (DiGeorge syndrome), and Turner syndrome.
• Family History: Having a parent or a sibling with a congenital heart defect slightly increases the risk of having a child with CHD.
• Maternal Medical Conditions:
  • Pre-existing diabetes in the mother can increase the risk.
  • Rubella: A maternal infection with rubella (German measles) during pregnancy can cause heart defects.
  • Lupus: Women with this autoimmune disease have a slightly higher risk.
• Maternal Medication Use: The use of certain medications during pregnancy has been linked to an increased risk of heart defects. These include some anti-seizure medications, lithium, and isotretinoin for acne.
• Alcohol or Drug Use during pregnancy.

Clinically, I counsel parents that CHD is not caused by anything they did or didn’t do, although certain maternal infections, alcohol use, or poorly managed chronic conditions can contribute to risk.

Signs and symptoms of CHD depend entirely on the type and severity of the defect. Some mild defects may cause no symptoms for many years, while severe defects cause critical illness immediately after birth.

Signs in a Newborn or Infant

Severe or “critical” CHDs often present in the first few hours or days of life.

• Cyanosis: A persistent bluish discoloration of the skin, lips, and fingernails.
• Rapid Breathing (Tachypnea): Breathing much faster than normal.
• Difficulty Feeding: The baby may tire easily during feeding, sweat, or breathe rapidly while eating.
• Poor Weight Gain.
• A Heart Murmur: An extra or abnormal sound heard when a doctor listens to the heart with a stethoscope. While many murmurs are innocent, some can be a sign of a structural heart problem.

Signs in Older Children, Adolescents, and Adults

Milder defects may not be diagnosed until later in life.

• Becoming easily tired or short of breath during exercise or physical activity.
• An inability to keep up with peers during play.
• Swelling in the hands, ankles, or feet (edema).
• In some cases, fainting (syncope) during exertion.

Clinically, I always consider CHD in a newborn with a heart murmur, low oxygen levels, or poor weight gain. Some milder forms may not be detected until later in childhood.

Thanks to advances in medical imaging, many serious heart defects are now diagnosed before a baby is even born.

Prenatal Diagnosis

• Fetal Ultrasound: A routine anomaly scan during the second trimester of pregnancy can often detect a major structural heart problem.
• Fetal Echocardiogram: If a problem is suspected, a maternal-fetal medicine specialist or pediatric cardiologist will perform a fetal echocardiogram. This is a detailed, specialized ultrasound that focuses solely on the baby’s heart, providing clear images of its structure and blood flow. A prenatal diagnosis is invaluable, as it allows the medical team to plan for a safe delivery at a specialized center with a pediatric cardiac team ready to care for the baby immediately after birth.

Postnatal Diagnosis

• Newborn Pulse Oximetry Screening: In many hospitals, a simple, painless test is performed on all newborns before discharge. A small sensor is placed on the baby’s hand and foot to measure the oxygen level in their blood. A low oxygen level is a major red flag for a critical congenital heart defect.
• Physical Examination: The diagnosis is often first suspected when a pediatrician hears a heart murmur or notices cyanosis during the newborn exam.
• Echocardiogram: An echocardiogram is the gold standard and most important tool for diagnosing CHD after birth. This non-invasive ultrasound provides detailed, moving pictures of the heart’s chambers, valves, and blood vessels, allowing a cardiologist to precisely identify the defect and assess its severity.
• Other Tests: A chest X-ray, an electrocardiogram (ECG), and in more complex cases, a cardiac MRI or cardiac catheterization may also be used.

In my experience, prenatal ultrasounds sometimes catch major defects, but postnatal evaluation is often needed to fully understand the nature and severity of the heart problem.

Treatment of CHD is highly individualized and depends on the specific type and severity of the defect. A pediatric cardiologist manages care and, when needed, a congenital heart surgeon at a specialized center.

1. Observation

Simple defects, such as a small ASD or VSD, may not put any strain on the heart and may not require any treatment at all. Some small holes may even close on their own over time. These conditions are simply monitored with periodic check-ups.

2. Medications

Medications cannot fix a structural defect, but they can be used to manage the symptoms or complications. This can include diuretics to reduce fluid buildup or drugs to help the heart pump more efficiently.

3. Cardiac Catheterization Procedures

For certain types of defects, a minimally invasive procedure can be performed. A cardiologist threads a thin tube (a catheter) through a blood vessel in the groin up to the heart.

• Device Closure: For some ASDs and VSDs, a special mesh device can be deployed through the catheter to plug the hole.
• Balloon Valvuloplasty: A catheter with a balloon on its tip can be inflated inside a narrowed valve to stretch it open.

4. Open-Heart Surgery

For most moderate to complex CHDs, open-heart surgery is required to repair the defect. The timing of the surgery depends on the specific condition.

• Some repairs are done in infancy, while others may be done later in childhood.
• For the most complex defects, such as Hypoplastic Left Heart Syndrome, a series of three planned open-heart surgeries over the first few years of life may be necessary to completely re-route the blood flow.

5. Lifelong Care

It is crucial to understand that even after a successful surgical repair, a person with a history of CHD requires lifelong follow-up care with a cardiologist who specializes in congenital heart disease. As these individuals grow into adulthood, they will transition their care to an Adult Congenital Heart Disease (ACHD) specialist.

Clinically, I emphasize a team-based approach, pediatric cardiologists, surgeons, and often geneticists collaborate to personalize care, especially for complex conditions like Tetralogy of Fallot or hypoplastic left heart syndrome.

A diagnosis of congenital heart disease is a challenging and emotional start to a family’s journey. It is a path that often involves complex medical procedures, hospital stays, and a lifetime of specialized care. However, it is also a path illuminated by incredible hope. The progress in pediatric cardiology and congenital heart surgery over the past half-century has been one of the great triumphs of modern medicine. Procedures that were once considered impossible are now performed routinely. Clinically, I’ve found that early diagnosis, parental support, and regular follow-up are the cornerstones of managing congenital heart disease effectively.

Centers for Disease Control and Prevention (CDC). (2024). Facts about Congenital Heart Defects. Retrieved from https://www.cdc.gov/ncbddd/heartdefects/facts.html

American Heart Association. (n.d.). About Congenital Heart Defects. Retrieved from https://www.heart.org/en/health-topics/congenital-heart-defects/about-congenital-heart-defects

National Heart, Lung, and Blood Institute (NHLBI). (2022). Congenital Heart Defects. Retrieved from https://www.nhlbi.nih.gov/health/congenital-heart-defects