Atrial Septal Defect Diagnosis, Treatment and Cost

The diagnosis of atrial septal defect (ASD) is usually based on a combination of symptom history, physical examination, and targeted cardiac investigations, which together help the cardiologist confirm the condition. ASDs can be detected before birth, during childhood (often incidentally via murmurs), or in adulthood and are managed based on their size, location, and whether they cause symptoms such as shortness of breath, fatigue, or recurrent chest infections.

To determine the most appropriate diagnostic approach, the cardiologist considers the following factors before selecting tests to diagnose atrial septal defect:

• Medical history
• Physical examination
  
  

Medical history

• In atrial septal defect, the medical history may reveal symptoms of left-to-right shunting and increased pulmonary blood flow. Patients may complain of breathlessness on exertion, easy fatigability, recurrent respiratory tract infections in childhood, poor growth, or palpitations in adulthood. 
• Some individuals remain asymptomatic for many years, with symptoms appearing later due to progressive right heart enlargement or pulmonary hypertension. These historical features raise suspicion of an underlying congenital cardiac defect such as ASD.

Physical examination

• Physical examination can provide important signs that raise suspicion of an atrial septal defect. On auscultation, the doctor may detect a characteristic, wide and fixed splitting of the second heart sound, caused by delayed pulmonary valve closure. A soft systolic ejection murmur may be heard due to increased blood flow across the pulmonary valve rather than the defect itself. 
• In long-standing cases, signs of prominent right ventricular impulse, elevated neck veins, or features of heart failure may be present. These findings prompt confirmatory testing with cardiac imaging.

✅Atrial Septal Defect (ASD) Tests

Based on the above information, a cardiologist recommends diagnostic tests to confirm the presence of an atrial septal defect and assess its size, direction of shunting, type, and possible complications such as right heart enlargement, pulmonary hypertension, or arrhythmias.

The following tests might be recommended for the diagnostic evaluation of atrial septal defects:

Prenatal diagnosis of atrial septal defect (before birth)

• Routine antenatal ultrasound
• Fetal echocardiography (18–24 weeks of gestation)

Postnatal diagnosis of atrial septal defect (after birth)

• Primary imaging studies
• Transthoracic echocardiogram (TTE) with colour Doppler
• Electrocardiography (ECG)
• Chest X-ray
• Advanced and confirmatory tests
• Transesophageal echocardiogram (TEE) 
• Cardiac computed tomography (CT) 
• Magnetic resonance imaging (MRI) scan
• Cardiac catheterisation
• Functional tests
• Exercise testing
  
  

Prenatal diagnosis of atrial septal defect (before birth)

Prenatal diagnosis focuses on identifying defects before birth to enable early counselling, monitoring, and postnatal management planning. Advances in fetal imaging allow the detection of structural heart abnormalities during routine antenatal care. Diagnosis is usually made using the following methods:

Routine antenatal ultrasound

• During a routine antenatal ultrasound, usually performed in the second trimester, the fetal heart is examined as part of the standard anomaly scan. An atrial septal defect may be suspected if there is an abnormal appearance or discontinuity of the atrial septum, disproportion in chamber sizes, or abnormal blood flow patterns. 
• However, small atrial septal defects can be difficult to detect on routine scans. Larger defects or indirect signs, such as right atrial or right ventricular enlargement, can raise suspicion and prompt referral for detailed cardiac evaluation.

Fetal echocardiography (18–24 weeks of gestation)

• Fetal echocardiography provides high-resolution images of the atrial septum and uses colour Doppler imaging to assess blood flow between the atria, performed between 18 and 24 weeks of gestation. If ASD is present, it is identified by directly visualising a defect or absence in the atrial septal tissue and by detecting abnormal predominantly left-to-right or bidirectional blood flow across the septum. 
• This technique can accurately define the type, size, and location of the atrial septal defect, as well as identify associated cardiac anomalies.
  
  

Postnatal diagnosis of atrial septal defect (after birth)

Postnatal diagnosis of ASD helps in identifying the defect after birth, particularly in infants or children who present with cardiac murmurs, recurrent respiratory infections, poor growth, or exercise intolerance.

Diagnosis of ASD is confirmed using the following approaches:

Primary imaging studies

• Transthoracic echocardiogram (TTE) with colour Doppler: This is the primary and most important imaging test for diagnosing an atrial septal defect, which provides direct visualisation of the interatrial septum. A defect appears as a discontinuity or opening in the septum between the right and left atria. Also, colour Doppler is important for the demonstration of abnormal blood flow across the atrial septum, showing left-to-right shunting. TTE also helps assess the size and type of ASD, enlargement of the right atrium and right ventricle, and increased pulmonary blood flow, all of which support the diagnosis.
  
• Electrocardiography (ECG): In patients with significant ASDs, the ECG may show features such as right axis deviation, right atrial enlargement, or right ventricular hypertrophy, reflecting chronic volume overload of the right heart. Certain ECG patterns, like incomplete right bundle branch block, are commonly associated with secundum-type ASDs. These electrical changes help suggest the diagnosis and indicate the physiological impact of the defect on cardiac function.
  
• Chest X-ray: Chest X-ray shows cardiomegaly, particularly enlargement of the right atrium and right ventricle, due to long-standing left-to-right shunting. Increased pulmonary blood flow can lead to pulmonary plethora(prominent pulmonary vascular markings due to increased pulmonary blood flow (perfusion) to the lungs), which is visible as prominent pulmonary vascular markings. And in advanced cases, signs of pulmonary hypertension may be present. 

Advanced and confirmatory tests

• Transesophageal echocardiogram (TEE) : This allows clear visualisation of small or complex atrial septal defects that may be missed on transthoracic echocardiography. Colour Doppler imaging accurately demonstrates shunting of blood across the septum, confirming the presence, size, and exact location of the defect. TEE is especially valuable in adults, in suspected sinus venosus ASDs, and when planning device or surgical closure.
  
• Cardiac computed tomography (CT): This helps to identify an atrial septal defect by clearly outlining the anatomy of the interatrial septum and visualising abnormal communications between the atria. CT is useful when echocardiographic windows are poor or when assessing associated structural abnormalities. 
  
• Magnetic resonance imaging (MRI) scan: Cardiac MRI is a non-invasive tool that provides both anatomical and functional assessment of atrial septal defects. It can directly visualise the defect in the atrial septum and accurately measure right atrial and right ventricular enlargement caused by chronic left-to-right shunting. 
  
• Cardiac catheterisation: Cardiac catheterisation is an invasive confirmatory test used when non-invasive imaging is inconclusive or when pulmonary hypertension is suspected. An atrial septal defect is diagnosed by detecting an oxygen saturation step-up in the right atrium, indicating left-to-right shunting. The procedure also accurately calculates shunt size and directly measures intracardiac pressures and pulmonary vascular resistance, which is essential before deciding on ASD closure in complex or advanced cases.
  
  

Functional tests

• Exercise testing: Exercise testing plays an important role in evaluating the functional impact of the defect on the cardiovascular system. During graded exercise, patients with significant ASDs may demonstrate reduced exercise tolerance, early fatigue, or shortness of breath due to an inability to appropriately increase cardiac output.

✅Atrial Septal Defect Differential Diagnosis

Differential diagnosis is considered when patients present with signs such as a cardiac murmur, fixed splitting of the second heart sound, right heart enlargement, or signs of pulmonary overcirculation. Several congenital and acquired cardiac conditions can mimic the clinical and echocardiographic findings of ASD. Below are some important conditions that can mimic or resemble ASD symptoms: 

• Atrioventricular septal defect (AVSD, also called AV canal defect): This condition involves defects of both the atrial and ventricular septa along with abnormal atrioventricular valves. It may mimic an atrial septal defect because it produces left-to-right shunting and right-sided chamber enlargement, but it features a "goose-neck" deformity on echo and often AV valve regurgitation.
• Pulmonary stenosis: This causes right ventricular pressure overload and a systolic murmur that can resemble the findings of an atrial septal defect (ASD), though it typically shows a pressure gradient across the valve on echo/Doppler without interatrial shunting.
• Total anomalous pulmonary venous return (TAPVR): This particular condition can resemble atrial septal defect because it leads to right heart volume overload and increased pulmonary blood flow. The main difference is that pulmonary veins drain into the right atrium or systemic veins instead of the left atrium, with no interatrial communication on imaging.
• Tricuspid atresia: Tricuspid atresia may resemble severe ASD because blood must pass across the atrial septum to reach the left heart, sometimes producing cyanosis. However, it is characterised by the absence of the tricuspid valve and a hypoplastic right ventricle, confirmed by absent tricuspid inflow on echo. 
• Truncus arteriosus: This congenital anomaly can present with pulmonary overcirculation and heart failure symptoms, which are similar to ASD, but features a single arterial trunk and VSD.
• Ventricular septal defect (VSD): VSD may mimic ASD due to left-to-right shunting and increased pulmonary blood flow. However, the defect is located in the ventricular septum and typically produces a harsh pansystolic murmur, best heard at the left sternal border.
• Arrhythmias: Atrial arrhythmias such as atrial fibrillation or flutter (and supraventricular tachycardia in younger patients) can cause symptoms like dyspnea, palpitations, and reduced exercise tolerance, which may resemble ASD but lack shunting on echo.

✅Considerations of a cardiologist before treating atrial septal defect (ASD)

Before planning treatment for an atrial septal defect, a cardiologist analyses the factors listed below:

• Treatment decisions: These are influenced by a patient's age and the occurrence of symptoms such as dyspnea, recurring lung infections, or decreased exercise tolerance. Early closure in childhood can help prevent long-term problems. However, adult patients need to carefully weigh the risks and benefits, with closure typically recommended for defects >10 mm with right ventricular enlargement or symptoms.
• Associated cardiac and extracardiac anomalies: The cardiologist checks for associated congenital heart defects, valve abnormalities, or anomalous pulmonary venous return. These may alter the treatment approach and often require surgical rather than percutaneous repair.
• Risk of arrhythmias and stroke: Long-standing ASD increases the risk of atrial arrhythmias and paradoxical embolism. A history of stroke, transient ischemic attack, or atrial fibrillation strengthens the indication for closure, even in borderline cases, especially if Eisenmenger syndrome is developing.
• Suitability for device and surgical closure: Anatomical factors, such as rim adequacy around the defect, proximity to valves or venous structures, and overall septal morphology, determine whether transcatheter device closure is feasible or whether open surgical repair is safer.
• Patient comorbidities and overall health: Other medical conditions, including lung disease, renal dysfunction, or connective tissue disorders, are considered, as they may increase procedural risk or influence timing and method of intervention.

✅Atrial Septal Defect Treatment Goals

The main treatment goals for ASD are:

• To prevent long-term heart and lung complications: Treating ASD stops abnormal left-to-right blood flow, preventing right heart enlargement, pulmonary hypertension, arrhythmias, and heart failure.
• To ensure normal growth and function: Closure of the defect restores normal circulation, allowing proper heart and lung function and supporting normal growth and physical development, especially in children.
• To improve quality of life: Treatment reduces symptoms such as breathlessness and fatigue, improves exercise tolerance, and lowers the risk of future complications, leading to a better overall quality of life.