ASD – Atrial Septal Defect

An atrial septal defect (ASD) is an opening or hole in the wall that separates the two upper chambers of the heart. This wall is called the atrial septum. The hole causes oxygen-rich blood to leak from the left side of the heart to the right side. This causes extra work for the right side of the heart since more blood than necessary is flowing through the right ventricle.

ASD Diagnosis
Most atrial septal defects (ASD) are discovered during childhood when a murmur, an extra heart sound is heard during a physical examination.
To help diagnose ASD in adulthood, your doctor also may suggest the following tests:

• Electrocardiogram (EKG or ECG), which records the heart’s electrical activity
• Chest X-ray to see the heart’s size
• Echocardiogram, which is an ultrasound examination of the heart
• In addition, your doctor may use a cardiac catheterization procedure to inject a dye into the heart and to see on a moving picture X-ray how the heart and aorta are functioning.

Risk Factors
It not known why atrial septal defects occur, but congenital heart defects appear to run in families and sometimes occur with other genetic problems, such as Down syndrome. If you have a heart defect, or you have a child with a heart defect, a genetic counsellor can estimate the odds that any future children will have one.
Some conditions that you have or that occur during pregnancy may increase your risk of having a baby with a heart defect, including:

• Rubella infection – Becoming infected with rubella (German measles) during the first few months of your pregnancy can increase the risk of foetal heart defects.
• Drug, tobacco or alcohol use, or exposure to certain substances – Use of certain medications, tobacco, alcohol or drugs, such as cocaine, during pregnancy can harm the developing foetus.
• Diabetes or lupus – If you have diabetes or lupus, you may be more likely to have a baby with a heart defect.
• Obesity – Being extremely overweight (obese) may play a role in increasing the risk of having a baby with a birth defect.
• Phenylketonuria (PKU) – If you have PKU and aren’t following your PKU meal plan, you may be more likely to have a baby with a heart defect.

ASD Complications
A small atrial septal defect usually does not cause any problems. Small atrial septal defects often close during infancy.
Larger defects can cause serious problems, including:

• Right-sided heart failure
• Heart rhythm abnormalities (arrhythmias)
• Increased risk of a stroke
• Shortened life span
Less common serious complications may include:
• Pulmonary hypertension – If a large atrial septal defect goes untreated, blood flow to your lungs increases thereby raising the blood pressure in the lung arteries (pulmonary hypertension).
• Eisenmenger syndrome – Pulmonary hypertension can cause permanent lung damage. This complication, called Eisenmenger syndrome, usually develops over many years and occurs uncommonly in people with large atrial septal defects.
• Treatment can prevent or help manage many of these complications.

ASD Prevention
Atrial septal defects can’t be fully prevented. But a few precautions can be taken by a regular visit to your doctor and by getting these done:

• Rubella testing and getting vaccination
• Review health conditions and medications.
• Reviewing family medical history and genetic predisposition

Symptoms

Many children have no symptoms and seem healthy. However, if the ASD is large, permitting a large amount of blood to pass through to the right side of the heart, the right atrium, right ventricle, and lungs will become overworked, and symptoms may be noted. The following are the most common symptoms of atrial septal defect. However, each child may experience symptoms differently. Symptoms may include:

• Child tires easily when playing

• Fatigue and sweating

• Swelling of legs, feet or abdomen

• Rapid breathing and shortness of breath

• Heart murmur – a swooshing sound which can be heard using a stethoscope.

The symptoms of an atrial septal defect may resemble other medical conditions or heart problems. Always consult your child's physician for a diagnosis.

Causes

The heart is forming during the first 8 weeks of fetal development. It begins as a hollow tube, then partitions within the tube that eventually become the septa (or walls) dividing the right side of the heart from the left. Atrial septal defects occur when the partitioning process does not occur completely, leaving an opening in the atrial septum.

It is believed that some congenital heart defects may have a genetic link, either occurring due to a defect in a gene, a chromosome abnormality, or environmental exposure, causing heart problems to occur more often in certain families. However doctors are unsure and find that atrial septal defects occur sporadically (by chance), with no clear reason for their development.

FAQ

What are the types of ASD?
There are five types: patent foramen ovale, ostium secundum defect, ostium primum defect, sinus venosus defect, and coronary sinus defect.

What are the symptoms of ASD?
Getting tired easily, shortness of breath, fast breathing, slow growth, respiratory infections. Heart arrythmias may or may not be present.

Is ASD life threatening?
ASD is not usually dangerous if corrected promptly but severe cases of atrial septal defects may lead to life-threatening complications such as chest pain, irregular heartbeats, abnormal enlargement of the heart, a “fluttering” of the heart (atrial fibrillation).

What are the treatment options available for ASD?
ASD can be repaired non surgically or by surgery. Non-surgical treatment uses closure devices called septal occluders which are inserted using catheters from large veins of the leg. This device seals the hole over which tissue grows eventually and the device becomes a part of the heart. ASD can be repaired surgically using tissue patches. In addition to this the doctor also prescribes blood thinning medications which needs to be taken for a period of 6-12 months depending upon the recovery status of the patient.

How can I prevent ASD from occurring?
ASD is a congenital disease which cannot be prevented.

What are the precautions to be taken in a child suffering from ASD?
Usually there is no exercise limitations. If you have other problems, such as an irregular heartbeat, PH, heart failure associated in a diagnosed case of ASD, the cardiologist may advice certain activity restrictions and life style changes.

If I (and adult) have an ASD, can I get pregnant?
Small sized ASDs usually don’t pose any problems if the you are trying to get pregnant but a female having larger unrepaired ASD with additional heart risk have an increased risk for complications during pregnancy and after delivery.

What are the complications that can arise if ASD is not treated?
Infection of the heart valves, congestive heart failure, arrythmias, stroke, pulmonary hypertension etc.

What is atrial septal defect?
It is cardiac congenital condition present at birth characterized by hole between the walls of the upper two chambers of heart. This communication between the two upper chambers of heart leads to increased work load on lung arteries which may get damaged if the hole is not fixed.