Atrial Septal Defect: The hole in the heart that can be missed

Jun 09, 2019 Dr Zulfikar Bux, Features / Columnists

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By Dr Zulfikar Bux

Assistant Professor of Emergency Medicine

An atrial septal defect (ASD) is a hole in the septum between the heart’s two upper, or collecting, chambers (atria). The septum is a wall that separates the heart’s left and right sides.

Everyone is born with a natural hole between the collecting chambers of the heart. This hole is known as the foramen ovale. It is very important while the baby is in the womb as it directs oxygen-rich blood from the mother’s placenta towards the baby’s brain and heart.
After birth, this opening is no longer needed and closes itself in most individuals. However, in up to one in five healthy adults, a small opening may remain. This is known as a patent foramen ovale.
The ASD is larger than a patent foramen ovale and may or may not be in the same place as the natural hole. ASDs are the third most common heart defect that babies can be born with and account for 10% of heart defects. While there are other holes that occur in the heart, ASDs are often subtle and go unnoticed until later in life.
Today we will discuss this subtle but worrisome condition.

WHAT ARE SYMPTOMS OF AN ATRIAL SEPTAL DEFECT?
Many babies born with atrial septal defects don’t have associated signs or symptoms. In adults, signs or symptoms may begin around age 30, but in some cases signs and symptoms may not occur until decades later.
Atrial septal defect signs and symptoms may include:
• Shortness of breath, especially when exercising
• Fatigue
• Swelling of legs, feet or abdomen
• Heart palpitations or skipped beats
• Stroke
• Heart murmur, a whooshing sound that can be heard through a stethoscope

WHAT ARE THE PROBLEMS WITH AN ATRIAL SEPTAL DEFECT?
ASDs usually do not cause any problems in childhood. Many defects which are small will close as the child grows. However, the child needs to be under regular follow-up of a heart specialist. If the hole does not close itself then it needs to be closed. This is usually done at around 4-5 years of age.
Large ASDs allow a significant amount of blood to leak from the left collecting chamber of the heart to the right collecting chamber and then into the right pumping chamber. This gradually stretches and damages the right side of the heart. That is why these defects are closed in a planned manner at about 5 years of age.
However, ASDs are not always diagnosed in childhood. Therefore, adults with undiagnosed ASD can present with shortness of breath, especially with exercise. They can also experience a feeling of having a ‘thumping’ heart (palpitations) because of heart rhythm problems.
HOW IS AN ATRIAL SEPTAL DEFECT DIAGNOSED?
Diagnosis of an ASD can occur when someone presents with the above symptoms recurrently or upon a doctors’ examination. The doctor will hear an abnormal sound called a “murmur” when he listens to the heart. The doctor will follow up with an ultrasound of the heart called an echocardiogram. The echocardiogram will give more details on the size of the ASD and help determine the type of surgery that will be needed.
WHAT CAN BE DONE TO HELP?
Babies and children with small holes just need regular check-ups by a children’s heart specialist. Many of the small holes close on their own. If the hole has not closed by 5 years of age, it can be surgically closed. Most holes can be closed by a keyhole procedure, using a small blocking device. The device is inserted through a blood vessel so there is no need for open heart surgery. Some holes, because of their large size or their location, cannot be closed by keyhole procedure. These holes require open heart surgery. All these procedures are done in specialist units dealing with children’s heart surgery.
WHAT IS THE OUTLOOK LIKE WITH AN ASD?
Most children in whom the hole is found during childhood do very well. In many, the hole closes on its own. If the hole closes on its own or is closed during childhood, then the function of the heart usually remains normal.
If the hole is not closed, then regular follow-up is needed. However, there are usually no problems and the person can lead a normal life with no restriction of activity. When the hole is diagnosed late in life, there may have been some damage to the heart’s pumping ability. Then there may be some symptoms such as shortness of breath and the feeling of having a ‘thumping’ heart (palpitations). Closing the hole usually produces some improvement but some symptoms may persist.
This article is dedicated to a little champ that is close to me and has an ASD. She has more heart than any kid I know. You got this little champ!

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