Atrial septal defect: definition, causes, treatment, perspectives

An atrial septal defect is a congenital heart problem. According to the Centers for Disease Control and Prevention (CDC), it develops in about 1 in 1,859 babies in the United States.

It is a hole in the wall inside the heart known as the septum, which divides the left and right atrium. According to 2018 research, this condition is the third most common type of heart irregularity seen in newborns.

Small holes often repair themselves. But the doctors generally recommend surgical closure of medium or large defects even if they do not cause symptoms. This can help prevent problems or complications later in life.

To understand what an atrial septal defect is, it helps to know how the heart works.

Your heart is made up of four chambers. The two upper chambers are your left and right atria and the lower chambers are your left and right ventricles. The blood circulates in these chambers in a definite order:

  1. Oxygen-poor blood flows from your body to your right atrium.
  2. It then flows from your right atrium into your right ventricle, which pumps it to your lungs.
  3. The oxygen-rich blood then returns from your lungs to your left atrium.
  4. It flows from your left atrium to your left ventricle, which pumps it to the rest of your body.

This article will take a closer look at the different types of atrial septal defects, how they are diagnosed and treated, and what the outlook is for this type of heart disease.

Doctors divide atrial septal defects into four main categories, depending on where the hole is:

  • Ostium secundum defect. This is when the hole grows in the middle part of your septum. This is the most common type. According to a 2015 review, it represents about 75 percent of cases.
  • Ostium primum defect. In this case, the hole grows in the lower part of your septum. This type of interatrial communication accounts for approximately 15 to 20 percent of cases.
  • Venous sinus defect. With this type, the hole grows into the upper part of your septum. A Case Study 2019 suggests that sinus venous has a lower rate of spontaneous closure than other types.
  • Coronary sinus defect. This is when the hole grows in the wall that separates your left atrium from your coronary sinus. Coronary sinus defects are the rarest type.

An atrial septal defect is a congenital defect, which means that it is present from birth. According to CDCthe cause of most atrial septal defects is not known.

Every baby is born with an opening between the upper chambers of the heart. This hole carries blood away from the lungs while a baby is in the womb. Opening is no longer necessary once a baby is born and closes within weeks to months, depending on the American Heart Association (AHA). If the hole is larger than usual, it may not close after birth.

Mutations in genes may play a role in the development of certain heart defects. A combination of genetic factors and exposure to certain chemicals in the womb can also contribute to these changes.

Ostium primum defects occur frequently in people with Down syndrome or Ellis-van Creveld syndrome.

Symptoms of an atrial septal defect are often mild and usually not noticeable during infancy. the CDC says that some babies with severe birth defects may have symptoms such as:

  • frequent infections
  • fatigue when breastfeeding
  • caress

The most common sign in childhood, and often the only sign, is a heart murmur. Children with severe abnormalities, especially ostium primum abnormalities, may have symptoms such as:

A 2011 study found that up to 33.8 percent of adults with unrepaired atrial septal defects have heart palpations.

Early diagnosis and screening are important and usually lead to favorable outcomes, according to research 2020. Older studies found that 90 percent of people with untreated large atrial septal defects do not live to their 60th birthday.

Atrial septal defect is often not diagnosed until late childhood or adulthood. Small faults may cause no noticeable symptoms.

Atrial septal defects are most often diagnosed when a doctor listens to your heart through a stethoscope and detects a murmur.

If a doctor hears a murmur, they may order a special ultrasound of your heart called an echocardiogram. This type of diagnostic test uses sound waves to produce live images of your heart. This allows your doctor to see inside your heart, how well it is working and how blood is flowing through it.

Another diagnostic tool your doctor may order is a transesophageal echocardiogram. With this procedure, a thin probe will be passed down your throat into your the esophagus, which is close to the upper chambers of your heart. The probe will then use high frequency sound waves to produce detailed images of the structures inside your heart.

The severity of an atrial septal defect depends on:

  • hole size
  • how much blood goes through
  • in which direction the blood moves

The left side of your heart usually pumps blood to your body, while the right side pumps blood to your lungs. A hole between your atria can cause oxygenated blood to flow back into the right side of your heart.

This pooling of blood can increase pressure in the blood vessels that supply your lungs. For many years, this pressure can damage your heart and lungs.

Small holes less than 5 millimeters (about 0.2 inches) can heal on their own within a year of birth. Defects larger than 1 centimeter (about 0.4 inches) are most likely to require treatment to avoid complications later in life.

On half septal defects resolve on their own without treatment, according to a 2017 study. The other half require treatment with either a procedure called cardiac catheterization and percutaneous closure or open-heart surgery.

watchful waiting

When an atrial septal defect is diagnosed in a young child, doctors often recommend waiting carefully to see if the hole will close on its own. The doctor may prescribe medication to treat the symptoms during this time.

Cardiac catheterization

Doctors can use a procedure called cardiac catheterization to treat heart defects without opening the chest. During this procedure, your cardiologist inserts a thin, flexible tube into a blood vessel in your leg or neck. Then they thread it all the way to your heart and deploy a closure device to plug the hole.

This procedure has a lower risk of complications than open heart surgery but can only be used for ostium secundum defects.

open heart surgery

Open-heart surgery is usually performed from early childhood. Surgery may be necessary if the hole is large or is not an ostium secundum defect.

the AHA says small, unrepaired holes rarely cause problems later in life. They usually don’t require you to limit your physical activity or change your lifestyle.

People with larger defects are more likely to need treatment. Your cardiologist may recommend certain lifestyle changes until you can receive treatment and while you are recovering from your treatment.

You can usually return to your usual activities once you have fully recovered and have had a post-treatment checkup with your doctor. Once the hole is closed, follow-up surgery is rarely needed and you can live an active life.

An atrial septal defect is one of the most common congenital heart irregularities. It happens when there is a hole between the two upper chambers of the heart. If the hole is small, it may heal on its own. Larger holes may require treatment to prevent complications later in life.

Many people don’t know they have ASD until late childhood or adulthood. If you are diagnosed with an atrial septal defect, your doctor can provide more information about what type of defect it is and what treatment is right for you.

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