From the Guidelines
The most common types of atrial septal defects (ASDs) are ostium secundum, ostium primum, sinus venosus, and coronary sinus defects, with ostium secundum being the most prevalent, accounting for 70-75% of ASDs, as defined by the American College of Cardiology/American Heart Association task force on clinical data standards 1. The classification of ASDs is crucial for determining the appropriate management strategy, as each type has distinct anatomical locations, embryological origins, and associated cardiac anomalies that influence clinical presentation, diagnostic approach, and treatment options.
- Ostium secundum defects occur in the central portion of the interatrial septum at the fossa ovalis due to excessive resorption of the septum primum or deficient growth of the septum secundum.
- Ostium primum defects occur at the lower part of the atrial septum and are often associated with atrioventricular valve abnormalities as part of atrioventricular septal defects.
- Sinus venosus defects are located near the entry of the superior vena cava (superior type) or inferior vena cava (inferior type) and frequently associate with partial anomalous pulmonary venous return.
- Coronary sinus defects are the rarest form, involving a defect in the wall between the coronary sinus and the left atrium. Echocardiography, particularly transesophageal echocardiography, plays a significant role in the diagnosis and assessment of ASDs, as highlighted in the 2018 AHA/ACC guideline for the management of adults with congenital heart disease 1. The choice of treatment, whether percutaneous device closure or surgical repair, depends on the type of ASD, with secundum-type defects being amenable to percutaneous closure, while primum, sinus venosus, and coronary sinus ASDs require surgical closure due to the absence of appropriate rims for percutaneous device placement and the proximity of the atrioventricular valves and conduction system to the closure device 1.
From the Research
Types of Atrial Septal Defects
- There are four types of atrial septal defects (ASDs): ostium secundum, ostium primum, sinus venosus, and coronary sinus defects 2
- Ostium secundum defect is the most common type of ASD and accounts for 60-70% of all cases 3
- Ostium secundum ASD is amenable to percutaneous occlusion, while other types usually require surgical correction 2
Characteristics of Ostium Secundum ASD
- Ostium secundum ASD is characterized by a defect in the interatrial septum that allows pulmonary venous return to pass from the left to the right atrium 3
- Symptoms of ostium secundum ASD may be absent or subtle, and may take 30-40 years to develop 3
- Echocardiography can establish the size and location of the ASD, the magnitude and hemodynamic impact of the left-to-right shunt, and the presence and degree of pulmonary hypertension 3
Treatment Options for ASD
- Transcatheter closure of ASD using devices such as the Amplatzer septal occluder is a safe and effective treatment option for ostium secundum ASD 4, 5
- Surgical closure of ASD is also a safe and effective treatment option, but may be more suitable for complex cases or cases where transcatheter closure is not possible 6
- Transcatheter closure has been shown to have benefits over surgical closure, including lower complication rates and shorter hospital stay 6