Atrial septal defect
In patients with a congenital defect affecting the wall (septum) between the two atria, the upper chambers of the heart, blood flows from the left side into the right side of the heart. This abnormal circulatory pattern puts excessive strain on the right ventricle and may cause heart failure. Nowadays, this type of defect can be repaired using either open surgery or catheter-based procedures.
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What is an atrial septal defect?
The term atrial septal defect (ASD) refers to a "hole" in the wall between the top two chambers of the heart, the atria. ASD is one of the most common congenital heart defects, and is significantly more common in girls than in boys. Due to a pressure gradient between the two upper chambers of the heart, blood flows from the left atrium into the right atrium - over time, this places excess strain on the right atrium. Sometimes, ASD may occur in patients with congenital
What are the main symptoms?
In rare cases, an atrial septal defect will lead to poor growth and the development of heart failure in babies and young children. As a rule, symptoms associated with heart failure only develop once the patient reaches adolescence or, if the defect is a minor one, when the patient reaches middle age:
- Shortness of breath
- Reduced exercise capacity
- Cardiac arrhythmias
- In severe cases, normal pulmonary circulation may be impaired, leading to chronic oxygen deficiency in the body's tissues. Typical symptoms are the enlargement - "clubbing" - of the terminal segments of the fingers ("drumstick fingers") and curving of the nails ("watch-glass nails").
What are possible causes?
Atrial septal defect is a congenital heart defect. The condition is generally thought to be caused by a combination of different genetic and environmental factors. In most cases, however, the exact causes remain unclear.
Diagnosis of atrial septal defect
- Atrial septal defect produces characteristic heart sounds, which can be listened to using a stethoscope (auscultation). Auscultation, performed as part of screening tests during infancy, can therefore provide crucial information to prompt further investigation.
- Cardiac ultrasound scan (echocardiography): this test provides information on the nature and extent of the defect.
- Cardiac catheterization is particularly advised if other findings are inconclusive. In some cases, a heart defect may even be able to be repaired immediately, as part of the same catheter-based procedure.
Treatment for atrial septal defect
- Open heart surgery
- Catheter-based procedures
Open heart surgery
An atrial septal defect can be repaired with open heart surgery. Depending on the size of the defect, the surgeon may close the hole with sutures or with a patch made from pericardial tissue or synthetic material. This type of surgical procedure is performed using cardiopulmonary bypass (a heart-lung machine), and usually involves sternotomy (cutting through the patient's breastbone). In some cases, however, minimally-invasive procedures may be possible, with access via a small incision in the side of the chest ( between the ribs).
In some particularly severe cases, a heart transplant may be necessary.
Catheter-based procedures
An atrial septal defect may also be repaired using a special expandable umbrella-like device, which is positioned inside the atrium using a catheter inserted via a blood vessel in the groin. This type of procedure has gained importance over the past few years. Wherever possible, surgeons will now choose this type of procedure over conventional surgery. Catheter-based procedures are usually performed under general anesthesia.