Atrial Septal Defect

An Atrial Septal Defect is an inherited heart defect that includes a hole in the atrial septum. There is an increase in the amount of blood that flows through the lungs which is because of the hole in the atrial septum. Small atrial septal defects usually close during infancy or early childhood and do not cause much of a concern. On the other hand, a large and long-term atrial septal defect can harm or damage the heart and lungs.

The four common types of Atrial Septal Defects are mentioned as following :

1. Sinus Venosus ASDs – These are located in the upper or lower back part of your atrial septum. Sinus venosus ASDs cause a defect in the right pulmonary vein or large veins in the heart also known as superior vena cava.
2. Primum ASDs – These are located in the lower part of your atrial septum. Infants that develop primum ASDs have higher chances of other heart defects as well. These primarily involve endocardial cushion defect, atrioventricular  septal defect, tricuspid valve defects and mitral valve defects. These are generally linked with Down Syndrome.
3. Secundum ASDs – These are located in the middle of your atrial septum. Usually, 80% of the ASD fall under the category of Secundum ASDs.
4. Unroofed Coronary Sinus – This is the rarest type of ASD bringing with itself less than 1% of ASDs. It also includes a distance in the form of an incomplete wall between your coronary sinus and your left atrium.

The signs and symptoms of Atrial Septal Defect may vary from person to person. Below are some known symptoms of ASD. Though, an atrial septal defect is present at birth but may not show any signs and symptoms until far into adulthood.

Symptoms of an ASD in children

Most children have no signs or symptoms while some other may show symptoms as follows – 

1. Being underweight
2. Growth Delays 
3. Recurrent respiratory infections

Children with larger ASDs may have symptoms that include:

1. Arrhythmias
2. Easily becoming fatigued when exercising
3. Trouble breathing

Symptoms of an ASD in adults

Adults with ASD may feel symptoms by age 40. Symptoms depend on how much the ASD has strained the heart and lungs. They include:

• Fatigue
• Shortness of breath with exercise
• Heart palpitations
• Fast heartbeat (tachycardia)
• Swelling in the arms and legs
• Blue skin color (cyanosis).

The diagnosis of Atrial Septal Defect is done through a physical examination alongside a few tests that keep a check on your heart’s functioning.

Your healthcare advisor will diagnose Atrial Septal Defect by conducting the following investigations:

1. Electrocardiography (ECG) – An ECG is a test that can be used to check your heart’s rhythm and electrical activity. It can be used to investigate symptoms of a possible heart problem, such as chest pain, dizziness and shortness of breath.
2. Chest X-Ray – The chest x-ray is performed to evaluate the lungs, heart and chest wall. It will also show if the blood vessels in your lungs are affected.
3. Transthoracic Echocardiography (TTE) – This is the most common type of echocardiogram, which is a still or moving image of the internal parts of the heart using ultrasound. It also depicts details related to pulmonary hypertension.
4. Transesophageal Echocardiography (TEE) – This is an ultrasound taken via esophagus. It depicts the size, shape and location of an ASD. It can also check your heart valves.
5. Intracardiac Echocardiography (ICE) – This is an ultrasound taken inside your heart which shows the size and shape of the ASD and the direction of the blood flow across it. A tiny camera is placed inside your heart via a peripheral vein.
6. Cardia CT Scan – In some cases, Cardiac CT scan or Heart MRI are performed for people with associated defects or less common forms of ASD. 

The actual cause of Atrial Septal Defect isn’t exactly fully known. Though, genetic changes often lead to heart defects that take place before birth. Some of the factors that may cause a risk of having a baby with congenital heart disease are as follows:

1. Alcohol consumption
2. Smoking and tobacco use
3. Taking certain prescription medications

There are some certain health conditions that may increase a baby’s risk of atrial septal defect. These factors involve :

1. German Measles infection during the first few months of pregnancy
2. Diabetes
3. Lupus
4. Alcohol or tobacco use
5. Illegal drug use like cocaine
6. Anti-seizure medications and drugs to treat mood disorders

For the treatment of atrial septal defect, surgery or percutaneous repair can be taken into consideration. The timing and type of ASD treatment depends on factors as follows-

1. ASD type and size 
2. Affect of ASD on your heart
3. Pulmonary hypertension, valve disease or coronary artery disease 

Usually, small ASDs don’t need repair. Whereas, larger ASD’s must be repaired even if there aren’t any signs and symptoms. If you show symptoms of heart or lung damage, repair is essential. Your Atrial Septal Defect doctor will ask you to undergo treatment in the following cases – 

1. The right side of your heart is bigger than normal.
2. There is significant flow of blood through the ASD.

You might consume some medications to treat the symptoms of ASD but there is no medication that can close the hole altogether.

In case you have pulmonary hypertension, you may need to take medication prior to your repair procedure. 

Percutaneous repair of ASDs

This kind of repair uses a device commonly known as a septal occluder which closes the hole in your atrial septum. This device is placed using a long, thin tube known as a catheter. The occluder is attached with the catheter, which is guided to your heart via a  vein in your groin.