Atrial Septal Defect – Symptoms and Causes
What is an Atrial Septal Defect?
An atrial septal defect (ASD) is a congenital heart condition, meaning people are born with it. This condition creates a hole between the upper chambers of the heart. This opening causes more blood than normal to flow through the lungs.
Some small ASDs may be discovered accidentally and cause no problems. In certain cases, these holes close on their own during early childhood. However, larger ASDs that remain open for a long time can harm both the heart and lungs.
In these cases, surgical repair may become necessary to prevent complications.
Common ASD Types
Several types of atrial septal defects exist, each affecting different parts of the heart:
- Secundum ASD: The most frequent type, occurring in the middle section of the wall (atrial septum) between the upper heart chambers.
Primum ASD: Found in the lower portion of the wall between upper chambers, often appearing alongside other congenital heart issues.
Sinus Venosus ASD: A rare form typically located in the upper section of the wall between heart chambers, frequently accompanied by other structural heart abnormalities.
- Coronary Sinus ASD: An uncommon type where part of the wall separating the coronary sinus (part of the heart’s vein system) from the left upper heart chamber is missing.
Treatment options depend on the size and location of the defect, as well as the individual’s overall health condition.
Signs and Symptoms
People born with a hole in the wall between the heart’s upper chambers might not show any signs early in life. These symptoms often develop later, as they become adults.
Common symptoms include:
- Breathing difficulties, especially during physical activity
- Fatigue or feeling tired often, particularly after exercise
- Swelling in the legs, feet, or abdomen
- Irregular heartbeats
- Heart palpitations (feeling your heart skip, flutter, or pound)
When to Get Medical Help
Doctors often find serious heart defects around birth or during early childhood. Seek emergency medical attention immediately if your child has trouble breathing.
Contact a healthcare provider if you or your child experiences:
- Shortness of breath, particularly during physical activities
- Getting tired easily after exercise
- Swelling in the lower body or abdomen
- Heart palpitations or irregular heartbeats
These symptoms might indicate a heart problem that needs medical evaluation and treatment.
Why Atrial Septal Defects Happen
Atrial septal defects form during pregnancy as the baby’s heart develops. While the exact cause remains unclear, several factors may contribute to this heart structure problem:
- Genetic changes can affect how the heart forms
- Certain medical conditions in the mother
- Medications taken during pregnancy
- Smoking during pregnancy
- Alcohol misuse while pregnant
The Heart’s Normal Function
The heart contains four chambers that work together to pump blood throughout the body. The upper chambers (atria) and lower chambers (ventricles) have specific roles in this process.
Blood flows from the right side of the heart to the lungs where it collects oxygen. This oxygen-rich blood returns to the left side of the heart, which then pumps it through the aorta (the body’s main artery) and out to the rest of the body.
When someone has a large atrial septal defect, extra blood travels to the lungs. This forces the right side of the heart to work harder than normal.
Without treatment, this extra work causes the right side of the heart to enlarge and weaken over time. The increased blood flow can also raise pressure in the lung arteries, leading to a condition called pulmonary hypertension.
The heart’s normal structure includes a wall (septum) between the left and right atria. In atrial septal defects, an abnormal opening exists in this wall, disrupting the heart’s normal blood flow pattern.
Risk Factors
Several factors may increase the chance of a baby developing an atrial septal defect (ASD) during pregnancy:
- Getting rubella (German measles) in early pregnancy
- Maternal diabetes or lupus
- Drinking alcohol or using tobacco while pregnant
- Using cocaine during pregnancy
- Taking certain medications during pregnancy, especially those for seizures or mood disorders
ASD and other heart defects can run in families. If you or a family member was born with a heart problem, tell your healthcare provider.
Health Issues
Women with atrial septal defects (ASDs) should speak with healthcare providers before becoming pregnant. Proper medical guidance is essential during this time.
Small ASDs may not cause problems, as they often close naturally during infancy. However, larger holes between the heart’s upper chambers require careful monitoring.
For those with significant ASDs, doctors might recommend repair before pregnancy. This is because large defects can create complications during pregnancy, making it high-risk.
Potential complications of untreated ASDs include:
- Heart failure affecting the right side
- Irregular heart rhythms
- Stroke risk
- Shortened lifespan
- High blood pressure in lung arteries
If left untreated, the increased pressure in lung blood vessels can cause permanent damage. This serious condition, known as Eisenmenger syndrome, typically develops gradually over many years in people with large ASDs.
Prevention
There is no clear way to prevent atrial septal defect (ASD) since the exact cause remains unknown. However, proper prenatal care plays a key role in overall fetal health.
If you were born with an ASD and plan to become pregnant, schedule a health checkup first.
During your pre-pregnancy appointment:
- Discuss your current health conditions and medications. Health issues like diabetes and lupus need careful management during pregnancy.
Your doctor might need to adjust or stop certain medications before you conceive.
- Review your family health history. A family pattern of heart defects might suggest higher risks.
A genetic counselor can help assess your situation if heart defects run in your family.
- Get tested for German measles immunity. Also called rubella, this infection during pregnancy has been linked to heart defects in babies.
If you haven’t had rubella or been vaccinated against it, get the recommended vaccine before trying to conceive.
