AUTHOR AND EDITOR INFORMATION

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INTRODUCTION

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Background

Congenital heart defects are common in children, with an incidence of approximately 8 cases per 1000 live births. These defects cause an array of problems in the primary care of children. An understanding of human embryology is essential for diagnosing these abnormalities and in planning long-term treatment.

Pathophysiology

Cardiac tissues are first detectable on the 18th or 19th day of fetal life. Cardiac development continues for the next several weeks. The atrial septum begins to form during the fourth week of gestation and is complete by the end of 5 weeks' gestation.

Classic model of cardiac development

According to the classic model of cardiac development, the process begins when a thin crescent-shaped membrane (septum primum) begins to form along the dorsal and cranial walls of the atrium. The space between the septum primum and the endocardial cushions (ostium primum) becomes progressively smaller as the septum primum grows toward the endocardial cushions. Before the ostium primum completely closes, small perforations develop in the anterosuperior wall of septum primum and ultimately coalesce to form a second interatrial communication, the ostium secundum. Meanwhile, the leading edge of the septum primum fuses with the endocardial cushions, and the ostium primum disappears.

Near the end of 5 weeks' gestation, the second phase of the process begins when a second crescent-shaped membrane (septum secundum) begins to form within the atrium to the right of the first septum. This membrane also begins to grow toward the endocardial cushions, covering the ostium secundum. However, the septum secundum remains incomplete. The foramen ovale is the opening remaining after the septum secundum completely forms.

The final phase of the process begins when the upper portion of the septum secundum proceeds to degenerate and finally disappears. The fully formed atria now have 2 overlapping but incomplete septae. The upper portion of the septum secundum covers the ostium secundum and creates a one-way valve allowing right-to-left shunting of blood in the fetus.

Van Praagh and Corsini model of cardiac development

Van Praagh and Corsini proposed another model of cardiac development.¹ According to their model, the septum primum (also known as the flap valve of the foramen ovale) grows from the portion of the left venous valve of the sinus venosus that is furthest left. As it extends from the most dorsal aspect of the atrium, the septum primum begins to meet the septum secundum, which is an invagination of the most rostral portion of the primitive atrium. The marginal edges of the septum primum eventually meet the left aspect of the septum secundum.

During embryonic and fetal life, the central portion of the septum primum billows into the left atrium due to the normal right to left shunting at the atrial level. After birth, the remainder of the septum primum adheres to the left aspect of the septum secundum.

Recent identification of an anomaly called deviated superior attachments of septum primum provides evidence in favor of the Van Praagh and Corsini model. Additional detailed morphologic analysis of murine cardiac development is needed to determine which model is correct.

Types of atrial septal defects

Four basic types of atrial septal defects (ASDs) are known. Patients who simultaneously have the first 3 types of ASD, as described below, are said to have common atrium.

The first type is an ostium secundum defect. The most common yet least serious type of ASD is an ostium secundum defect. This defect occurs in the area of the fossa ovalis and presumably results from excessive fenestration or resorption of septum primum, underdevelopment of septum secundum, or some combination of the 2 conditions.

In approximately one half of patients with left atrioventricular (AV) valve underdevelopment (ie, hypoplastic left heart syndrome or Shone complex), the superior attachments of the flap valve of the foramen ovale lie on the left atrial roof, well to the left of the septum secundum. Weinberg et al (1986) called this anomaly "(leftward and posterior) deviation of the superior attachments of septum primum."² This deviation is observed extremely rarely in patients with a normal-sized left AV valve. Of importance, the classic model does not explain its existence well. This type can be regarded as a variation of an ostium secundum defect, although it is most rigorously designated as a malalignment-type ASD.

A second variant of the ostium secundum defect is its association with an aneurysm of the atrial septum. This is thought to be due to redundancy of the valve of the fossa ovalis. It may be associated with mitral valve prolapse or atrial arrhythmias (see Media files 1-3).

The second type is an ostium primum defect. This ASD presumably results from failure of the endocardial cushions to close the ostium primum. Because endocardial cushions also form the mitral and tricuspid valves, ostium primum defects are virtually always associated with a cleft in the anterior mitral valve leaflet (see Media files 4-6).

The third type is a sinus venosus defect. This ASD is found in the posterior aspect of the septum near the superior vena cava (where it may coexist with partial anomalous pulmonary venous connection of the right upper pulmonary vein) or the inferior vena cava (where it may coexist with partial anomalous pulmonary venous defect of the right lower pulmonary vein) (see Media file 7).

The fourth type is a coronary sinus septal defect. This least common type of ASD is called an unroofed coronary sinus or coronary sinus septal defect. A portion of the roof of the coronary sinus is missing; therefore, blood can be shunted from the left atrium into the coronary sinus and subsequently into the right atrium. This type is often associated with a left superior vena cava.

Left-to-right shunting

Clinical effects of isolated ASDs are usually related to left-to-right shunting. The magnitude of shunt is related to the size of the defect in the septum, to the relative compliance of the left-sided and right-sided cardiac chambers, and indirectly related to the resistance of the pulmonary and systemic circulations. At birth, the right and left ventricles are of equal thickness and similar compliance. In the first few days to weeks after birth, the pulmonary vascular resistance (PVR) remains mildly elevated and has not reached its nadir.

As impedance to pulmonary blood flow decreases and the right ventricle becomes more compliant, blood is able to flow to the pulmonary vascular bed more easily, and the atrial level left-to-right shunt increases. 

On occasion, the septal defect is small, with little left-to-right shunting. However, most defects that cause murmurs or symptoms are moderately large to large, and the size of the defect does little to limit left-to-right shunting. Approximately 15% of ostium secundum ASDs spontaneously close by age 4 years.

Frequency

United States

Research indicates that congenital heart disease (CHD) is diagnosed in 0.8% of children in the first year of life. ASD occurs in about 1 in 1500 live births, or approximately 7% of these children with CHD. About 15-30% of healthy adults have an unfused foramen ovale in which the valve functions normally but has failed to fuse. In these individuals, a cardiac catheter passed into the right atrium can pass into the left atrium through the foramen ovale (ie, probe-patent foramen ovale).

Mortality/Morbidity

In developed countries, mortality rate of ASD is low (<1%). Morbidity secondary to ASD is unusual and typically limited to 3 groups of patients, as follows:

• Perhaps 1% of infants with moderate or large (ie, nonrestrictive) ASDs but no ductus arteriosus have tachypnea and failure to thrive. In these individuals, the pulmonary artery pressure, when measured during catheterization or Doppler echocardiography, is at or near systemic level. Attempts to exclude mitral or left ventricular diastolic abnormalities as a cause of these hemodynamics must be undertaken; however, these attempts frequently yield equivocal data.
• Patients in whom ASDs go unrecognized until late childhood may develop arrhythmias (eg, atrial fibrillation) or pulmonary hypertension. ASDs that initially appear in middle-aged or elderly adults can indicate congestive heart failure (CHF).
• Patients with ASDs may have an embolic stroke as the initial presentation.

Sex

The female-to-male ratio is approximately 2:1.

Age

ASD, a congenital abnormality, is present at birth. However, in most cases, a murmur is not audible until the child is a few months old. Symptoms usually do not occur in individuals with ASD until late childhood, adolescence, or adulthood.

• Secundum type (ie, ostium secundum), sinus venosus, and unroofed coronary sinus defects are sometimes not diagnosed until the third decade of life.
• Ostium primum ASDs are usually diagnosed in the first few years of life because of mitral regurgitation murmur or an abnormal ECG.
• A common atrium (ie, a combination of sinus venosus, ostium secundum, and ostium primum defects) is usually diagnosed in the first few years of life because systemic venous blood and pulmonary venous blood often partially mix before entering each ventricle; this condition manifests as cyanosis. In addition, a common atrium may be associated with complex CHD, and patients may present relatively early because of other intracardiac abnormalities.

CLINICAL

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History

• Infants and young children with atrial septal defects (ASDs) are typically asymptomatic.
• Most ASDs are diagnosed after a suspicious murmur is detected during a routine health-maintenance examination.
• Even in symptomatic children with ASDs, clinical manifestations are often subtle and nonspecific. Some children with ASDs have poor weight gain, they remain somewhat small, and they may have exertional dyspnea or frequent upper respiratory tract infections.
• Relatively severe symptoms, such as arrhythmia, pulmonary artery hypertension, and pulmonary vascular obstructive disease (PVOD), are rare in children with ASDs. Some infants and young children with large defects may present with symptoms of congestive heart failure (CHF), especially if they have an associated lesion (eg, patent ductus arteriosus) or lung disease (eg, bronchopulmonary dysplasia and/or chronic lung disease).

Physical

Most children with ASDs are asymptomatic. In developed countries, the diagnosis is usually made during an evaluation of a suspicious murmur or during an evaluation of fatigue and exercise intolerance. ASDs that are not diagnosed in childhood can result in problems in adulthood.

• Upon initial evaluation, many children with ASDs appear completely healthy; however, careful physical examination often yields clues to the diagnosis.
• Patients with ASDs may have a precordial bulge, a prominent right ventricular cardiac impulse, and palpable pulmonary artery pulsations. All of these are signs of increased blood flow through the right side of the heart and pulmonary vascular bed.
• Upon auscultation of the individual with ASD, the first heart sound may be normal or split. The sound associated with closure of the tricuspid valve may be accentuated if blood flow across the pulmonic valve is increased and leads to a midsystolic pulmonary ejection murmur. This sound is best appreciated at the upper left sternal border and may be transmitted to the lung fields.
• Although the second heart sound may be normal in newborns with ASDs, it becomes widely split and fixed over time as pressures on the right side of the heart decrease. This fixed splitting occurs as the result of increased capacitance in the pulmonary vascular bed, leading to low pulmonary impedance and, therefore, a long hangout interval after the end of right ventricular systole. Fixed splitting of S2 is an important diagnostic finding in atrial-level shunting.
• A large shunt increases flow across the tricuspid valve, and the patient with ASD is likely to have a mid-diastolic rumble at the left sternal border.
• Mitral valve prolapse occurs with increased frequency in the presence of ASD and may be caused by compression of the left side of the heart secondary to enlargement of the right side.
• • In patients with mitral valve prolapse, an apical holosystolic or late systolic murmur often is heard radiating to the axilla.
  • A midsystolic click may be present, but this murmur can be difficult to detect in some patients with ASDs.
• Pulmonary vascular resistance (PVR) may increase through childhood, adolescence, and adulthood, resulting in PVOD. The rise in PVR and pulmonary artery pressure results in right ventricular hypertrophy, which, in turn, reduces right ventricular compliance and may subsequently reduce the degree of left-to-right shunting.
• • Upon physical examination, patients may have a prominent right ventricular impulse, but the previously noted diastolic tricuspid flow rumble and the systolic ejection murmur in the pulmonic area may be diminished.
  • The wide splitting of the second heart sound may narrow, and the pulmonic component of the second heart sound may become loud, with intensity equal to that of the aortic component.
• In all patients with common atrium, right-to-left shunting occurs, resulting in cyanosis, although this may be mild due to preferential streaming of blood across the respective atrioventricular (AV) valves.
• In adults with an unrecognized ASD, the left-to-right shunt may worsen if systemic arterial hypertension develops. The result may be left ventricular hypertrophy, reduced left ventricular compliance, and increased left-to-right shunt.

Causes

Although many cases of ASD are sporadic, ASD clearly has a genetic component and may be associated with genetic syndromes.

• Ostium secundum ASD is typically a part of the Holt-Oram syndrome, which is caused by mutations in the T-box transcription factor TBX5.³ This autosomal dominant disease also includes absent or hypoplastic radii and first-degree heart block.
• Ostium secundum, ostium primum ASD, or both may occur alone or with other lesions as part of other genetic syndromes, such as trisomy 21 (Down syndrome). For unknown reasons, sinus venosus defects are rare in Down syndrome, making common atrium similarly rare in this population.
• An autosomal dominant form of familial ASDs with incomplete penetrance has been detected.
• • Mutations in NKX2.5, a homeodomain-containing transcription factor, have been associated with ASDs with and without AV block.⁴ Additionally, mutations in GATA4, an important regulator of cardiac development, have been associated with ASDs.
  • Interactions between GATA4 and NKX2.5 and interactions between GATA4 and TBX5 may be the root of the cardiac defects seen with GATA4 mutations, which establishes a link among these genes.
  • Interestingly, a missense mutation in myosin heavy chain 6 (MHY6) has also been identified with an autosomal dominant form of ASD. MHY6 was previously described in late-onset hypertrophic cardiomyopathy. This gene is highly expressed in the developing atria and appears to be influenced by TBX5 and GATA4 mutations, again establishing a link between several genes.
  • The prognostic implications of the involvement of a sarcomeric protein with ASDs has yet to be fully elucidated. Further genetic analysis will likely yield other mutations and genetic links associated with familial ASDs.
• ASDs are found in children with fetal alcohol syndrome.

DIFFERENTIALS

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WORKUP

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Lab Studies

• In general, no specific laboratory studies are available to aid in the diagnosis of an atrial septal defect (ASD).
• Determinations of brain natriuretic peptide (BNP) levels may be helpful in infants and in some children with large ASDs and congestive heart failure (CHF) when their clinical symptoms are equivocal. BNP levels are elevated in patients with CHF.

Imaging Studies

• Plain radiographic findings in ASD are nonspecific but include right atrial and right ventricular dilatation, pulmonary artery dilatation, and increased pulmonary vascular markings. In general, an enlarged right atrium leads to overall cardiomegaly on the anteroposterior (AP) radiograph. Pulmonary artery dilatation results in a prominent hump between the aortic knob and the left ventricular contour on the AP radiograph. Although pulmonary vascular obstructive disease (PVOD) is rare, if it develops, the main pulmonary artery becomes large and the lung fields become oligemic.
• Two-dimensional and Doppler echocardiography have revolutionized the diagnosis of ASDs. These studies can effectively reveal both the extent of the defect and the degree of left-to-right shunting. In small patients, the anatomy is observed especially well on subcostal views; the anomaly called deviated superior attachments of septum primum is reliably observed with only the modified subcostal left oblique view.
• In older children, large adolescents, or adults, transesophageal echocardiography may be required to document an ASD because of limited transthoracic echocardiographic windows. This is particularly true if sinus venosus and unroofed coronary sinus type ASDs are present. Transesophageal echocardiogram may also be useful in small children with poor echocardiographic windows.
• Cardiac MRI may be useful in the diagnosis of sinus venosus or coronary sinus defects in both children and older individuals with poor echocardiographic windows.
• • In experienced hands, cardiac MRI can easily depict anomalous pulmonary venous drainage associated with sinus venosus defects and a left superior vena cava, which is often associated with coronary sinus defects.
  • In general, older children do not require sedation for cardiac MRI (this is not the case with transesophageal echocardiography).
  • Cardiac MRI can also be used to calculate the effective left to right shunt (Qp:Qs) and quantitate right ventricular volumes.
  • It generally should not be used in attempts to further define atrial septal anatomy when entertaining the possibility of percutaneous device closure because transesophageal echocardiography defines the margins of the ASD much more effectively. Additionally, cardiac MRI is not readily available at all centers and requires a considerable amount of technical expertise.
• CT angiography is a quick and effective means to identify pulmonary venous abnormalities associated with sinus venosus defects or to rule out suspected anomalous pulmonary venous return identified on echocardiography prior device closure. In children, similar to cardiac MRI, it is not an adequate modality to evaluate the atrial septal anatomy when assessing for the possibility of percutaneous closure. Additionally, CT angiography comes with the added side effect of radiation.
• In some instances, cardiac catheterization is needed to provide further hemodynamic information prior to intervention. Pulmonary-to-systemic flow can be accurately determined when symptoms and results of other imaging modalities do not correlate. Additionally, calculations of pulmonary vascular resistance can be performed if pulmonary hypertension is a concern. Ideally, a mechanism should be in place to perform percutaneous device placement if the defect is suitable for closure at the time of the hemodynamic catheterization.

Other Tests

• ECG most commonly demonstrates right-axis deviation, right ventricular hypertrophy, and an rSR' or rsR' pattern in the right precordial leads. The QRS duration is usually normal. However, the ECG may be normal, especially in infants and in young children with small defects (see Media file 8).
• Left-axis deviation with a superiorly oriented counterclockwise frontal-plane loop suggests an ostium primum ASD (see Media file 9).
• All types of ASD can result in prolonged PR intervals. This prolongation of internodal conduction may be related to the increased size of the atrium and a long internodal distance (which is a result of the defect).

Procedures

• Cardiac catheterization is rarely necessary in the preoperative evaluation of a child with ASD.
• Cardiac catheterization may be necessary if pulmonary hypertension is suggested to document PVR and to assess the response of PVR to vasodilator substances. It may also be necessary to evaluate associated lesions, especially in patients with more than one left-to-right shunt.
• • Findings on catheterization include a step-up in oxygen saturation from the superior vena cava to the right atrium (usually >10%), slightly increased right ventricular pressures, a small pressure gradient across the pulmonary valve (due to increased flow across a fixed valve orifice) and normal to mildly increased pulmonary artery pressures. If a large defect is present, the mean pressures in the right and left atria are identical.
  • The above being said, catheter-based interventions for the closure of selected secundum ASDs have become most common in pediatric patients. Although catheterization is rarely needed for diagnosis, it may be useful from a treatment standpoint. See Treatment for further details.

TREATMENT

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Medical Care

Medical therapy is of no benefit in children with asymptomatic atrial septal defects (ASDs).

• With the exception of ostium secundum types, ASDs are structural defects that do not spontaneously close. Surgical closure is ultimately required for most ASDs, other than ostium secundum ASDs. An ostium secundum ASD that measures 6 mm in diameter or smaller in the patient's first year of life is likely to spontaneously close; however, such closure is substantially slower than that of a typical small, muscular ventricular septal defect.
• Infants who are severely affected with an ASD and who develop congestive heart failure (CHF) may be treated as any other child with CHF from a left-to-right shunt. This treatment, which includes diuretics, digoxin, and afterload reduction, is covered in other articles.
• Arrhythmias associated with ASD are similarly uncommon in childhood but have become increasingly common with age. In fact, the development of atrial fibrillation may trigger CHF in adults with ASD who are younger than 40 years. Arrhythmias may result from atrial distention, and these individuals may require antiarrhythmic therapy until the ASD is repaired.
• Some children with an ASD develop recurrent respiratory tract infections, which may be poorly tolerated.
• Bacterial endocarditis prophylaxis is not necessary for the typical patient with an isolated ASD, regardless of the type of ASD. Prophylaxis is recommended prior to surgical repair if the ASD is part of complex cyanotic congenital heart disease (CHD).  Endocarditis prophylaxis is recommended for 6 months following either surgical or percutaneous repair of ASDs and, in some instances, may be recommended for longer in patients with residual mitral valve abnormalities after surgical repair of primum ASDs. For more information see Antibiotic Prophylactic Regimens for Endocarditis.⁵

Surgical Care

Definitive therapy for an ASD has historically been limited to surgical closure. However, with the advent of transcatheter techniques, many children undergo successful treatment in the cardiac catheterization laboratory.

• The most common surgical approach to the defect is primary repair with suture closure or with patch repair (generally with glutaraldehyde treated autologous pericardium or fabric made of polyester fiber [Dacron]).
• Not all children with an ASD are candidates for surgery, which is only indicated for those children with clinically significant left-to-right shunting.
• • In general, a pulmonary-to-systemic flow ratio of 1.5:1 or more is considered the principal indication for surgical repair. Shunting less than this in children with small defects and in those with existing pulmonary hypertension may be observed.
  • Because cardiac catheterization is rarely necessary, echocardiographic evidence of right atrial and right ventricular enlargement is usually considered evidence of a clinically significant left-to-right shunt and an indication for surgical closure of the ASD.
• Surgery is ideally performed in children aged 2-4 years and has a low mortality rate. However, surgery may be performed earlier than this if the child has evidence of CHF.
• Newer, minimally-invasive surgical techniques have been developed. These improve cosmetic appearances and decrease hospital stays. These techniques are ideally suited for simple closure of a secundum ASD.
• The surgical mortality rate is low in patients with uncomplicated ASDs. In an experienced pediatric center, the mortality rate should be less than 1%.
• Postoperative morbidity in individuals with ASDs is almost exclusively due to accumulation of pericardial fluid (postpericardiotomy syndrome), which occurs in approximately one third of patients. On occasion, tamponade occurs and requires pericardiocentesis. Pericardial effusion should be suspected in any pediatric patient who undergoes postsurgical repair of an ASD and who presents with chest pain, fever, shortness of breath, or general malaise. In young children, symptoms may be nonspecific and include irritability and decreased appetite.
• Transcatheter approaches to ASD closure have gained acceptance in the pediatric population.
• • Secundum ASDs are currently the only subtype of ASD that are amenable to this approach.
  • Such techniques require individuals with considerable expertise in the field of interventional pediatric cardiology and cooperation between the interventionalist and the noninvasive imaging specialists.
  • Benefits of the transcatheter approach include its minimal invasiveness, the lack of median sternotomy, the avoidance of cardiopulmonary bypass, and the relatively quick recovery time. Potential drawbacks and concerns include residual shunting around the device, embolization during placement requiring surgical intervention, lack of adequate septal rims to properly seat the device, long-term safety concerns, and the need for specific technical expertise and equipment. Although relatively new, transcatheter approaches for ASD closure are becoming prevalent, and studies are showing a high success rate.

Consultations

• Diagnosis of an ASD in a newborn or an older child should prompt consultation with a pediatric cardiologist.
• Almost all newborns have a small left-to-right shunt at the foramen ovale, as detected during echocardiography in the neonatal period. In the absence of a murmur or other signs of a true ASD on subsequent well-child care visits, consultation with a cardiologist is probably not necessary, although review of the initial echocardiogram report is prudent to verify the description of the defect.

Activity

• Children with ASDs generally have no restrictions on their activity.
• Children with compensated CHF with an ASD are candidates for surgical or catheter-based intervention and should be able to resume normal activity after the defect is corrected.

MEDICATION

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Medication is not currently a component of care for this condition. See Treatment.

FOLLOW-UP

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Further Inpatient Care

• Please refer to the sections regarding the specific subtypes of atrial septal defect (ASD) for potential inpatient issues.

Further Outpatient Care

• Provide routine medical care with special attention to signs of congestive heart failure (CHF) or increased pulmonary vascular resistance (PVR). Most patients with an ASD are asymptomatic and require only routine well-child care until they undergo elective surgical repair or transcatheter device placement for their defects.
• Most children with uncomplicated ASDs are followed up by their primary care provider and receive follow-up with a pediatric cardiologist every year or every other year. Children who require medical intervention are seen by a cardiologist more frequently than this.

Transfer

• An isolated ASD almost never causes clinically significant problems in the neonatal period or in infancy.
• Refer a child who is to have elective ASD surgical repair to a pediatric center with experience in performing cardiopulmonary bypass and surgical ASD closure in young children.
• A patient with an ostium primum ASD may have associated severe AV valve insufficiency and may require earlier surgical intervention. Refer this patient to a center with experience in the evaluation and repair of this problem.
• Any attempt at closure with a transcatheter device should be performed at a center with experience in pediatric interventional cardiology with surgical support.

Complications

• ASD is usually an asymptomatic disease. However, children with ASDs are at increased risk for several complications, such as endocarditis (if associated mitral valve insufficiency is present) and respiratory tract infections, which are less well tolerated in children with ASDs than in children without ASDs.
• Children with clinically significant and untreated ASDs are at risk for various cardiac complications, including CHF, pulmonary hypertension, and arrhythmias. However, these cardiac complications generally manifest in adulthood.

Prognosis

• The prognosis for a child with an ASD is good; the rate of surgical mortality is less than 1%. Many children are candidates for catheter-based device implantation, which also carries a very low procedural morbidity and mortality.
• Ostium secundum defects may spontaneously close. The likelihood of spontaneous closure appears to be closely related to the initial size of the defect. Some studies show that defects do not occur with ostium primum, sinus venosus, or coronary sinus defects.
• Certain patients with ostium primum ASDs and an abnormal mitral valves may require a second operation for mitral valve dysfunction later in their lives.

Patient Education

• Focus patient education on ensuring that the family and caregivers understand potentially serious symptoms so that they seek prompt medical attention when necessary.
• In addition, reassurance is often needed because of the stigmata associated with the diagnosis of congestive heart disease (CHD).
• Children may be unnecessarily restricted from activity.
• Education regarding care of an ASD and its complications also should include input from the cardiologist and cardiac surgeon.

MISCELLANEOUS

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Medical/Legal Pitfalls

• Failure to diagnose an atrial septal defect (ASD) in a child referred for evaluation of a murmur is a pitfall. A second examination is often necessary at a later time, especially if the initial examination is difficult in a young child or infant. However, in such circumstances, the family must be reliable regarding follow-up. In such circumstances, if findings on the repeat examination are still equivocal, echocardiography is warranted.
• Recommending closure of an ASD in a patient with pulmonary hypertension and advanced pulmonary vascular disease in whom repair of the defect is unlikely to yield benefit or likely to worsen the patient's condition is another pitfall.
• Recommending a transcatheter approach in a patient with a primum, sinus venosus, or coronary sinus ASD is a pitfall.

Special Concerns

• In the rare instance that a child has a hemodynamically significant ASD and ECG evidence of Wolff-Parkinson-White Syndrome, consideration should be given to performing an electrophysiologic study to evaluate the accessory pathway prior to closure of the ASD, either percutaneously or surgically. This is due to the possibility of a left-sided accessory pathway, which may be difficult to access after closure of the ASD.

MULTIMEDIA

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Media file 1:  Subcostal echocardiographic view of a child with a secundum atrial septal defect (ASD). Note the position of the defect in the atrial septum. RA = Right atrium; LA = Left atrium; SVC = Superior vena cava.
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Media type:  Echo

Media file 2:  Subcostal long-axis view of the same child as in Media file 1 with a secundum atrial septal defect (ASD). RA = Right atrium; LA = Left atrium; RUPV = Right upper pulmonary vein.
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Media type:  Echo

Media file 3:  Parasternal short axis view of a child with a secundum atrial septal defect (ASD). RA = Right atrium; LA = Left atrium; AO = Aorta.
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Media type:  Echo

Media file 4:  Apical echocardiographic view of a primum atrial septal defect (ASD). Note the position of the defect when compared with a secundum ASD. RA = Right atrium; LA = Left atrium; RV = Right ventricle; LV = Left ventricle.
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Media type:  Echo

Media file 5:  Apical echocardiographic view of a primum atrial septal defect (ASD). Note that the atrioventricular valves are at the same level (instead of mild apical displacement of the tricuspid valve), which is seen in the spectrum of atrioventricular canal defects. RA = Right atrium; LA = Left atrium; RV = Right ventricle; LV = Left ventricle.
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Media type:  Echo

Media file 6:  Apical color Doppler echocardiographic view of a primum atrial septal defect (ASD). Note the flow across the defect from the left atrium to the right atrium (RA), and note the mitral regurgitation (MR) through a cleft in the anterior leaflet of the mitral valve. MV = Mitral valve; LV = Left ventricle.
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Media type:  Echo

Media file 7:  Subcostal short-axis view of a child with a sinus venosus atrial septal defect (ASD). Note the position of the defect compared with that of a secundum or primum ASD. Also note the anomalous position of the right upper pulmonary vein (RUPV). RA = Right atrium; LA = Left atrium.
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Media type:  Echo

Media file 8:  ECGs from a child with a secundum atrial septal defect (ASD). Note the right-axis deviation and rSR' pattern in lead V1.
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Media type:  ECG

Media file 9:  ECG from a child with a primum atrial septal defect (ASD). Note the left-axis deviation with a counterclockwise vector of depolarization (small q waves in leads I and aVL) and right ventricular hypertrophy and/or volume overload (rSR' pattern and upright T wave in lead V1).
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Media type:  ECG

REFERENCES

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• References

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Article Last Updated: Oct 30, 2008