Atrial Septal Defect (ASD): Symptoms, Causes, Treatment, and Prevention

Many cases of ASD are considered idiopathic, which means no specific cause has been identified. However, several factors are known to increase the risk of a baby being born with ASD.

A healthy heart works efficiently, pumping oxygen-rich blood throughout the body. However, sometimes a baby is born with a heart condition that needs medical attention. One such condition is atrial septal defect (ASD).

Atrial septal defect (ASD) causes abnormal blood flow inside the heart, which affects how this vital organ performs. ASD can affect anyone, both children and adults, although its symptoms are often not immediately visible early in life.

It is important to learn more about ASD, including its types, symptoms, and treatment options, so that we can be more alert and responsive in dealing with this condition.

01 / Heart Disease

What Is Atrial Septal Defect (ASD)?

Atrial septal defect (ASD) is a congenital heart defect in which there is a hole in the atrial septum, the wall that separates the left and right atria of the heart. Normally, this septum prevents oxygen-rich blood from mixing with blood that carries carbon dioxide.

However, in people with ASD, the hole in the septum allows blood from both atria to mix, disrupting blood flow in the body. This can make the heart and lungs work harder than usual, which can potentially lead to further health problems if it is not properly treated.

Atrial septal defect (ASD) is one of the fairly common congenital heart defects, not only globally but also in Indonesia. In Indonesia, the prevalence of ASD is quite significant; ASD is the second most common congenital heart lesion among children after ventricular septal defect (VSD). According to estimates, the incidence of congenital heart disease (CHD) in Indonesia is around 32,000 to 40,000 cases each year, with ASD accounting for about 17% of these cases.

The following data gives an overview of the prevalence of ASD in Indonesia in the context of congenital heart disease as a whole:

Type of Congenital Heart Disease	Estimated Cases per Year	Percentage
Ventricular septal defect (VSD)	19,000 to 25,000	60%
Atrial septal defect (ASD)	5,440 to 6,800	17%
Other types	6,200 to 8,000	23%
Total	32,000 to 40,000	100%

Data sources show that globally, the prevalence of ASD is also quite high, estimated at around 1 in 2,000 live births. The condition is more common in females than in males, with a ratio of about 3:1.

Types of ASD

Atrial septal defect (ASD) can be divided into several types based on where the defect is located in the atrial septum. Each type has different characteristics and medical implications:

1. Ostium Secundum ASD: This is the most common type of ASD, occurring when there is a hole in the middle of the atrial septum, the dividing wall between the left and right atria. Ostium secundum ASD often causes no symptoms until adulthood and may be detected during a routine heart checkup. This hole allows oxygen-rich blood from the left atrium to mix with blood in the right atrium, which carries more carbon dioxide, increasing the volume of blood pumped to the lungs.
2. Ostium Primum ASD: This type of ASD involves a gap in the lower part of the atrial septum near where it joins the heart valves. This ASD is usually detected earlier, in childhood, and is often associated with other congenital heart defects, such as mitral or tricuspid valve abnormalities. Because of its location, ostium primum ASD can cause the heart valves to deteriorate, so treatment often requires further medical procedures.
3. Sinus Venosus ASD: This type of ASD is relatively rare and usually occurs in the upper part of the atrial septum, close to where the veins enter the right atrium. This hole can affect the direction of blood flow from the pulmonary veins to the heart, which sometimes causes other problems such as abnormal vein positioning. Diagnosing sinus venosus ASD may require more specific imaging procedures to get a detailed picture of the heart’s anatomy.

Each type of ASD has unique implications for blood circulation within the heart and may require a different treatment approach. That is why an accurate diagnosis and a consultation with a cardiologist are very important for determining the right treatment steps for people with ASD.

Causes of ASD

Atrial septal defect (ASD) is a congenital heart condition that occurs when the structure of the heart does not form completely during fetal development. The exact cause of ASD is still not fully understood, but several factors are thought to play a role in increasing the risk of this condition.

1. Known and Idiopathic Causes

Many cases of ASD are considered idiopathic, which means no specific cause has been identified. However, several factors are known to increase the risk of a baby being born with ASD:

• Genetics: A family history of congenital heart defects can increase a person’s likelihood of developing ASD. Some studies show a genetic link, in which mutations in certain genes can affect how the heart develops.
• Environmental Factors: Environmental factors during pregnancy, such as exposure to certain infections or the mother’s use of certain substances such as alcohol and illegal drugs, can affect the development of the baby’s heart.
• Maternal Health Conditions: Certain medical conditions in pregnant women, such as uncontrolled diabetes, can also increase the risk of congenital heart defects in the baby, including ASD.

2. Other Genetic and Health Factors

Studies show that ASD often occurs together with other genetic syndromes, such as Down syndrome *. In these conditions, a widespread genetic abnormality can affect how the heart’s structures form, increasing the risk of ASD. (* Source: Atrial Septal Defects in the Adult: Recent Progress and Overview)

The importance of comprehensive prenatal checkups cannot be overlooked, because early detection can help manage this condition from the start. A consultation with a genetics specialist may be needed if there are concerns about genetic risks in the family. With appropriate and timely treatment, many children with ASD can lead healthy, active lives.

02 / Heart Disease

Symptoms of Atrial Septal Defect (ASD)

The symptoms of ASD vary depending on the size of the defect, the patient’s age, and whether there are other heart abnormalities. Some people may have no symptoms at all, especially if the defect is small.

Symptoms in Children

In babies and children, the symptoms of atrial septal defect (ASD) may not be immediately visible because they often develop slowly. However, there are several signs parents can watch out for:

1. Shortness of Breath: The child may have difficulty breathing, especially during activity or when crying. This happens because the mixing of blood from both atria forces the heart and lungs to work harder.
2. Tiring Easily: Children with ASD may tire more quickly than their peers. This may be noticeable when they play or exercise.
3. Slow Growth: Some children with ASD may grow more slowly, including not gaining weight as expected for their age.
4. Recurrent Respiratory Infections: Frequent infections such as pneumonia or bronchitis may also indicate ASD, because abnormal blood circulation can weaken the lungs’ defenses.

Symptoms in Adults

In adults, the symptoms of ASD often go unnoticed until later in life because the body adapts to the condition. Symptoms that may occur include:

1. Palpitations: A fast or irregular heartbeat can occur due to an imbalance of blood flow within the heart.
2. Shortness of Breath During Exercise: Difficulty breathing or tiring quickly during physical activity is a common symptom caused by increased blood flow to the lungs.
3. Dizziness and Chronic Fatigue: People with ASD may feel mild dizziness and constant tiredness, which result from the heart working harder to maintain normal blood circulation.

When to See a Doctor

It is very important to consult a doctor promptly if you or your child show the symptoms mentioned above. Parents should stay alert and not ignore signs such as shortness of breath, extreme fatigue, or frequent respiratory infections.

Further tests such as echocardiography can be done to confirm the diagnosis and determine the right treatment steps. Detecting ASD early is very important to prevent further complications later in life.

03 / Heart Disease

Diagnosis of Atrial Septal Defect (ASD)

Diagnosing ASD involves several steps to confirm the presence and severity of the defect.

Physical Examination

A physical examination is an important first step. The doctor listens to the patient’s heartbeat with a stethoscope (auscultation). ASD often produces an abnormal heart sound or murmur, which can be a clue that a defect is present. The doctor also checks for other signs such as shortness of breath, cyanosis (bluish skin), and swelling in the legs.

Electrocardiogram (ECG)

An ECG is a simple test that records the heart’s electrical activity. In patients with ASD, an ECG may show changes in heart rhythm and in the pattern of electrical waves, which can indicate strain on the heart or arrhythmias related to ASD. However, an ECG alone is not always enough to diagnose ASD.

Echocardiography

Echocardiography is a noninvasive imaging test that uses sound waves to create images of the heart. It is the most important test for diagnosing ASD and assessing its severity. There are two main types of echocardiography:

• Transthoracic Echocardiography (TTE): This procedure is done from outside the chest and uses sound waves to create images of the heart. TTE can show the location and size of the hole in the atrial septum, as well as assess how the ASD affects blood flow and heart function. A transducer is placed on the patient’s chest to produce images of the heart.
• Transesophageal Echocardiography (TEE): TEE provides more detailed images than TTE. This procedure is done by inserting a transducer into the esophagus, bringing it close to the heart, to obtain clearer images of the heart’s structures. The transducer is placed in the esophagus to obtain more detailed images of the heart. This procedure requires light anesthesia and is more invasive than TTE. TEE is often done if TTE does not give adequate results.

Echocardiography allows the doctor to see the size and location of the defect, assess blood flow through the defect, and evaluate overall heart function.

Other Supporting Tests (If Needed)

In some cases, other supporting tests may be needed to obtain more detailed information or to evaluate related heart conditions. These tests may include:

• Cardiac Catheterization: An invasive procedure that involves inserting a thin catheter into a blood vessel to measure pressure and blood flow in the heart. Cardiac catheterization can provide more detailed information about the size and location of the defect, as well as assess the severity of the ASD.
• Cardiac CT Scan or MRI: Imaging tests that provide a detailed picture of the heart’s structure. They can help evaluate the overall anatomy of the heart and identify any other heart abnormalities.

The choice of supporting tests will be based on the patient’s symptoms, physical examination findings, and the results of the ECG and echocardiography.

04 / Heart Disease

Treatment of Atrial Septal Defect (ASD)

Treatment options for atrial septal defect (ASD) depend on several factors, including the size of the defect, the patient’s age, the symptoms experienced, and overall heart health.

Nonsurgical Treatment (If Applicable)

Some cases of atrial septal defect (ASD) can be managed without surgery, especially if the hole is small and does not cause significant health problems. In these situations, regular monitoring by a cardiologist may be enough to make sure no complications develop. Nonsurgical treatment may also involve the use of medications to control symptoms or complications, such as medications to reduce the heart’s workload or to treat an irregular heartbeat. Patients with a small ASD, no symptoms, or a high risk for surgery may be suitable for this approach.

ASD Surgery

If the ASD causes symptoms or a risk of serious complications, a surgical procedure may be needed. There are two main methods for closing an ASD:

• Transcatheter Device Closure of ASD (Percutaneous Closure): This procedure is minimally invasive and is done through a catheter inserted into a blood vessel in the groin. A small device is used to close the hole in the atrial septum. This method is suitable for holes of certain shapes and sizes and often allows faster recovery than open surgery.
• Open Heart Surgery (Surgical Closure): This is used for more complex cases or if the hole is too large to be managed with a catheter. In this surgery, the surgeon opens the chest and uses stitches or a patch to close the hole. It is a more invasive procedure with a longer recovery time, but it is often necessary so that the hole can be closed properly.

Postoperative Care

After undergoing an ASD closure procedure, whether transcatheter or open heart surgery, patients will need comprehensive postoperative care to support their recovery. This may include:

1. Rest: Getting enough rest is very important to allow the heart and body to recover. The recommended length of rest will vary depending on the type of procedure and the patient’s condition.
2. Medications: Patients may need medications to manage pain, prevent infection, or treat other complications. These medications may include anticoagulants, antibiotics, or other medications prescribed by the doctor.
3. Regular Checkups: Regular checkups and evaluations are very important to monitor the healing process, detect potential complications, and make sure the heart is functioning normally. The doctor will provide an appropriate follow-up schedule.
4. Physical Activity: The doctor will provide guidance on when and how the patient can gradually resume physical activity. It is important to avoid strenuous physical activity until sufficient recovery has been achieved.

Regular monitoring by medical staff is very important to make sure there are no postoperative complications and that the heart is working well after the ASD has been corrected.

05 / Heart Disease

Complications of Atrial Septal Defect (ASD)

Although ASD closure can help many patients, there are potential complications, both short-term and long-term.

Short-Term Complications

After undergoing a procedure to close an atrial septal defect (ASD), several short-term complications may occur, although they are generally rare and manageable. These complications include:

• Bleeding: Bleeding at the catheter insertion site (in transcatheter procedures) or at the surgical incision site (in open heart surgery) is a risk to watch out for.
• Infection: Infection can occur at the catheter insertion site or the surgical area. Preventing infection with antibiotics and proper sterile technique is very important.
• Reactions to Anesthesia: Allergic reactions or other side effects of anesthesia can occur in procedures that require anesthesia.
• Arrhythmias: Heart rhythm disturbances can occur temporarily after the procedure. ECG monitoring and appropriate treatment are needed if a significant arrhythmia occurs.
• Thrombosis (Blood Clots): The formation of blood clots in the heart or blood vessels is a rare but serious complication. Anticoagulants (blood thinners) may be given to reduce this risk.
• Pulmonary Embolism: A blood clot that breaks loose and travels to the lungs.

Long-Term Complications

If ASD is not treated, several long-term complications can occur, including:

• Pulmonary Hypertension (PHT): Increased blood pressure in the arteries of the lungs. This is caused by increased blood flow through the lungs due to the ASD. Severe PHT can lead to heart failure.
• Heart Failure: The heart has difficulty pumping blood effectively. This can happen if the ASD places an excessive workload on the heart over a long period.
• Stroke: ASD can increase the risk of stroke by allowing blood clots to form that can travel to the brain.
• Arrhythmias: Heart rhythm disturbances can develop over the long term, including atrial fibrillation (irregular beating of the upper heart chambers).
• Infective Endocarditis: An infection of the inner lining of the heart.

Although these complications are rare, especially after successful ASD closure, it is important to understand the potential risks and to have regular checkups and monitoring to detect complications early.

06 / Heart Disease

Prevention of Atrial Septal Defect (ASD)

Preventing ASD is a challenge because most cases are caused by genetic factors or unknown causes.

Primary Prevention

Completely preventing atrial septal defect (ASD) before birth is quite difficult because ASD is a congenital defect caused by various factors, including genetic and environmental factors during fetal development. However, there are several steps that can be taken to support the overall health of the fetus:

• Prenatal Care: It is important for pregnant women to receive good, regular prenatal care. Regular pregnancy checkups help the doctor monitor the development of the fetus and detect abnormalities as early as possible.
• Healthy Lifestyle: Pregnant women are advised to avoid smoking, alcohol, and illegal drugs, and to make sure they eat a balanced, nutrient-rich diet. This may minimize the risk of congenital heart defects.
• Health Control: Maternal medical conditions such as diabetes should be well controlled during pregnancy. Regular blood sugar checks and following medical advice are very important in reducing pregnancy risks that can affect the baby’s heart.

Secondary Prevention

Secondary prevention emphasizes the importance of detecting and treating ASD early to prevent further complications:

• Early Detection: Examinations using modern imaging technology such as echocardiography allow ASD to be diagnosed at an early age, even while the baby is still in the womb. This early detection is very important so that treatment can be given as early as possible to prevent complications.
• Early Treatment: If ASD is detected, a consultation with a pediatric cardiologist is very important to determine the right treatment or monitoring plan. ASD closure through a medical procedure can be done when needed, to help maintain heart function and reduce the risk of long-term complications such as pulmonary hypertension or heart failure.

With these primary and secondary prevention steps, the risk of serious complications from ASD can be minimized, and children can lead healthier lives.

07 / Heart Disease

Comparing ASD in Children and Adults

Atrial septal defect (ASD) can affect both children and adults, but its symptoms, diagnosis, and treatment can differ between these two age groups.

	Children	Adults
Symptoms	Often more obvious, and may include shortness of breath, tiring easily, stunted growth, recurrent respiratory infections, and a heart murmur that is clearly heard during auscultation. Some children may develop cyanosis (bluish skin) if the ASD is large enough.	Often more subtle and may go unnoticed until adulthood. Symptoms may include palpitations (a fast or irregular heartbeat), shortness of breath during exercise, dizziness, chronic fatigue, and reduced exercise tolerance. A heart murmur may not always be clearly heard.
Diagnosis	Made when a baby or young child is examined because of obvious symptoms or as an incidental finding during a routine physical examination. Echocardiography is the main imaging test to confirm the diagnosis.	ASD is often diagnosed after unexplained symptoms appear, through imaging tests such as echocardiography. In some cases, ASD is found by chance during a medical examination for another condition. An ECG and additional tests such as TEE or cardiac catheterization in more complicated cases can be used for a more accurate diagnosis.
Treatment	In children with a significant ASD, closure is usually recommended as early as possible to prevent long-term complications and ensure normal development of the heart and lungs. A transcatheter method or open heart surgery is chosen based on the size and location of the defect.	The decision to close an ASD in adults depends on the size of the defect, the symptoms present, and the severity of possible complications. If the ASD is small and causes no symptoms, monitoring alone may be done. However, if the ASD causes significant symptoms or complications such as pulmonary hypertension, closure is usually recommended. A transcatheter method or open heart surgery can be used depending on the patient’s condition and the characteristics of the defect.

Keep in mind that every case of ASD is unique. A cardiologist will evaluate each patient individually to determine the most appropriate treatment plan based on factors such as age, symptoms, the size of the defect, and the patient’s overall health.

08 / Heart Disease

Conclusion

Atrial septal defect (ASD) is a congenital heart defect characterized by a hole in the atrial septum, the wall that separates the right and left upper chambers of the heart. The size and location of this hole vary, and this affects the severity of symptoms and the need for treatment. Although some people with a small ASD may have no symptoms, this condition can cause serious complications if left untreated.

The symptoms of ASD can vary depending on age and the size of the defect. In children, symptoms may be more obvious, while in adults, symptoms are often more subtle and only appear later in life. Diagnosing ASD usually involves a physical examination, an ECG, and echocardiography, with other supporting tests that may be needed in some cases.

Treatment for ASD can involve observation (in certain cases) or a medical intervention to close the defect, either through a transcatheter procedure or open heart surgery. The choice of treatment method depends on several factors, including the size and location of the defect, the patient’s age, and their overall health. After an ASD closure procedure, postoperative care is needed to support optimal recovery and prevent complications.

The Importance of Early Detection and Treatment

Early detection and treatment of ASD are very important to prevent serious long-term complications, such as pulmonary hypertension, heart failure, stroke, and arrhythmias. Routine health checkups in children and timely medical evaluation when symptoms appear can help detect ASD as early as possible. Appropriate treatment may help improve patients’ quality of life and reduce the risk of illness and death associated with untreated ASD.