Atrial septal defect ostium secundum

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Atrial septal defect ostium secundum are ASDs at the level of fossa ovalis. It accounts for 75% of all atrial septal defects.

During fetal development, the septal wall may fail to fuse causing an atrial septal defect to arise. An ostium secundum atrial septal defect is one such type of malformation arising from the irregular development of the foramen ovale, septum secundum or septum primum. It is the most common type of atrial septal defect.

Although atrial septal defect ostium secundum defects occur sporadically, they are associated with and occur with higher frequency in certain genetic disorders.

Ostium secundum atrial septal defects are the most common form of atrial septal defect. They constitute approximately 60%-75% of all the atrial septal defects and account for 6%-10% of all congenital heart defects.

Most individuals with an uncorrected secundum ASD are asymptomic or experience minimal symptoms through early adulthood. About 70% of all ostium secundum ASD patients’ develop symptoms by the time they are in their 40s. Symptom onset and severity is largely dependent upon the size of the defect. Without intervention prior to the development of Eisenmenger’s syndrome, the mortality rate for symptomatic adults is greater than 50%. Possible complications include atrial fibrillation, pulmonary hypertension and stroke.

Echocardiography may be used as a diagnostic tool in the evaluation of an atrial septal defect. Common malformations of the septal wall include: ostium primum, ostium secundum, sinus venosus, and patent foramen ovale. Uncommonly, a defect may occur in the coronary sinus. Specific characteristics exist in echocardiography to identify these various classifications of atrial septal defects.

Definitive treatment of atrial septal defect involves surgical closure of the defect. Medical therapy has a limited role in the management of ASD, and is often used to manage complications like arrhythmia, congestive heart failure and other comorbidities associated with atrial septal defects such as stroke and migraine.

The decision to surgically close an atrial septal defect depends upon many contributing factors including the type of defect, the size of defect, the amount of left-to-right shunting, the development or worsening of symptoms, the presence of pulmonary hypertension and the presence of any associated anomalies.

Surgical closure is the commonest treatment method for atrial septal defect and has been the gold standard for many years. Many surgeons prefer more minimally invasive techniques over the conventional sternotomy to avoid potentials for additional complications. Special consideration must be taken into account for the age of the patient and the size of the defect involved. Surgical closure is indicated for patients with primum, sinus venosus and coronary sinus type of atrial septal defects. However, ostium secundum atrial septal defects are commonly treated by percutaneous closure. With uncomplicated atrial septal defect, (without pulmonary hypertension and other comorbidities) the post-surgical mortality is as low as 1%.

Percutaneous device closure is commonly performed to close an ostium secundum type of atrial septal defect and patent foramen ovales. It is still not FDA approved for closure of other forms of atrial septal defects such as primum, sinus venosus and coronary sinus. With proper patient selection at experienced centers, it has been found to be as successful, safe and effective as surgical closure. Additionally, it has been associated with fewer complications and a reduced length of stay compared to surgical closure. ^[1]

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editors-In-Chief: Priyamvada Singh, M.B.B.S. [2]; Cafer Zorkun, M.D., Ph.D. [3]; Assistant Editor-In-Chief: Kristin Feeney, B.S. [4]

During fetal development, the septal wall may fail to fuse causing an atrial septal defect to arise. An ostium secundum atrial septal defect is one such type of malformation arising from the irregular development of the foramen ovale, septum secundum or septum primum. It is the most common type of atrial septal defect.

• The septum secundum is semilunar in shape. It grows downward from the upper wall of the atrium immediately to the right of the primary septum and foramen ovale. Shortly after birth the septum secundum fuses with the primary septum and through this means the foramen ovale is closed. Sometimes the septal fusion is incomplete and the upper part of the foramen remains patent.

• The limbus fossae ovalis denotes the free margin of the septum secundum. The ostium secundum (or foramen secundum) is a foramen in the septum primum. It should not be confused with the foramen ovale, which is a foramen in the septum secundum. It can arises from an enlarged foramen ovale, inadequate growth of the septum secundum, or excessive absorption of the septum.

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Although atrial septal defect ostium secundum defects occur sporadically, they are associated with and occur with higher frequency in certain genetic disorders.

Most of ostium secundum ASDs occur sporadically. However, ostium secundum ASD has been found to occur with increased frequency in association with some genetic disorders including:

• Holt-Oram (heart-hand) syndrome
• Down syndrome
• Noonan syndrome
• Treacher Collins syndrome
• Thrombocytopenia-absent radii (TAR) syndrome
• Mitral valve prolapse: 10% to 20 % of individuals with ostium secundum ASDs also have mitral valve prolapse.^[1]

Template:WH Template:WS CME Category::Cardiology

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editors-In-Chief: Priyamvada Singh, M.B.B.S. [2]; Cafer Zorkun, M.D., Ph.D. [3]; Assistant Editor-In-Chief: Kristin Feeney, B.S. [4]

Ostium secundum atrial septal defects are the most common form of atrial septal defect. They constitute approximately 60%-75% of all the atrial septal defects and account for 6%-10% of all congenital heart defects.

It forms 30-40% of all congenital heart disease in patients aged 40 or older.

A female preponderance, with a female-to-male ratio of 2:1 has been found in the studies.

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Most individuals with an uncorrected secundum ASD are asymptomic or experience minimal symptoms through early adulthood. About 70% of all ostium secundum ASD patients’ develop symptoms by the time they are in their 40s. Symptom onset and severity is largely dependent upon the size of the defect. Without intervention prior to the development of Eisenmenger’s syndrome, the mortality rate for symptomatic adults is greater than 50%. Possible complications include atrial fibrillation, pulmonary hypertension and stroke.

As many atrial septal defect ostium secundum patients are asymptomatic, it is common to survive into adulthood without any need for intervention. Many atrial septal defects smaller than 8 mm in diameter close spontaneously during infancy. Spontaneous closure is uncommon in children and adults. During adulthood there can be the onset of symptoms and an altered life expectancy. Beyond 40-50 years of age, survival without intervention is under 50% with a mortality rate of about 6% per year.

Atrial septal defect ostium secundum is associated with complications such as

• Atrial fibrillation
• Pulmonary hypertension
• Heart failure
• Stroke

The prognosis for most atrial septal defect patients, especially prior to the age of 40, is positive. As atrial septal defect patients age, symptoms and complications may advance and influence quality of life. With surgical intervention, the mortality rate is less than 1% for atrial septal defect patients under 45. Surgical intervention in older populations is equally promising and can result in longer longevity and improvements in quality of life. Left untreated, the prognosis for atrial septal defect patients is significantly less favorable and may lead to earlier death.

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