Atrial septal defect (ASD) is an abnormal hole in the wall between the two upper chambers of the heart, called the right and left atria. When this hole occurs, too much blood flows from the left atrium to the right atrium and through the right side of the heart. This excess blood flows through the right ventricle, pulmonary artery and into the lungs making the heart work harder. The extra blood flowing to the lungs creates a noise called a murmur.
Patent foramen ovales (PFOs) are when the opening that allows blood to bypass the nonfunctioning fetal lungs during development remains open after birth.
As a group, atrial septal defects are detected in 1 child per 1,500 live births. PFOs are quite common, appearing in 10 – 20% of adults, but because they are asymptomatic they often go undiagnosed. ASDs make up 30 to 40% of all congenital heart disease that is seen in adults.
The ostium secundum atrial septal defect accounts for 7% of all congenital heart lesions. This lesion is twice as likely to appear in a female than a male.
Small holes may close on their own by the time a child is 2 years old. In some people, the defect doesn’t cause symptoms until middle age. A very large defect may allow so much blood flow through it to cause congestive heart failure symptoms such as:
- Shortness of breath
- Easy fatigability
- Poor growth
A large ASD causes several problems. The heart works harder because it pumps extra blood to the lungs, which may cause the right side of your heart to enlarge resulting in irregular heartbeats called arrhythmias. If left untreated, atrial septal defect may cause problems in adulthood. These problems may include:
- Pulmonary hypertension – which is high blood pressure in the lungs
- Congestive heart failure – weakening of the heart muscle
- An increased risk of stroke
All ASDs larger than a few millimeters in diameter should be closed to prevent these problems.
In some children an ASD may close on its own without treatment. With a small atrial septal defect, this may be as high as 80 percent in the first 18 months of life. An ASD still present by 3 years of age will probably never close on its own.
Closure of an ASD in individuals under age 25 has been shown to have a low risk of complications, and individuals have a normal lifespan. Closure of an ASD in individuals between the ages of 25 and 40 who are asymptomatic but have a clinically significant shunt is controversial. Those that perform the procedure believe that they are preventing long-term deterioration in cardiac function and preventing the progression of pulmonary hypertension. Methods of closure of an ASD include surgical closure and percutaneous closure.
Following closure of an atrial septal defect, there should be no problems with physical activity and no restrictions. Regular follow-up appointments will be made with a cardiologist.