In a healthy heart, blood passes from the left atrium to the left ventricle, which pumps it out of the heart to circulate throughout the body. After passing through all the organs, it enters the heart again in the right atrium. Then it passes to the right ventricle, which pumps it out to circulate through the lungs.
An atrial septal defect is a hole in the wall (septum) between the right and left atria. It allows blood to travel from the left atrium to the right. This means excess blood is circulating in the right side of the heart, and in the lungs. This causes extra work for the right ventricle, which can cause it to enlarge. This is called cardiomyopathy, and it is usually not serious when associated with ASD. The overwork and heightened blood pressure (pulmonary hypertension), can also damage the blood vessels in the lung.
Only children with serious ASD will have symptoms, including shortness of breath, fatigue, decreased appetite, failure to gain weight normally and excess sweating. Most ASDs are mild, however, and cause no symptoms. In fact, 40 percent of ASDs will close within the infant’s first year, and up to 80 percent of small ones close in the first 18 months.
If the patient exhibits no symptoms, the physician will first detect ASD when he or she finds a heart murmur during a routine examination. Echocardiography, electrocardiography and chest x-rays will then be used as a follow-up to find the cause of the murmur. If necessary, the more invasive cardiac catheterization procedure will be performed, but usually echocardiography can provide the same information.
If treatment is required, it might be performed during the cardiac catheterization procedure. A device can be inserted through a large vein and it adheres to the hole, closing it. If that is not possible, open heart surgery may be necessary.
