‘Hole in heart’ defect explained
What exactly does ‘hole in heart’ mean?
Atrial septal defect (ASD) is a congenital disorder (i.e. present at birth) of the heart that involves a hole in the wall (septum) that divides the two upper chambers of the heart.
The defect causes freshly oxygenated blood in the upper left chamber of the heart (or left atrium) to flow into the upper right chamber (right atrium) of the heart, causing mixing of oxygenated and deoxygenated blood. If the hole is large, the extra volume of blood that is pumped from the right side of the heart can lead to the following:
- Weakening of right side of the heart.
- Overfilling of lungs and overworking of heart.
- Increased blood pressure in lungs, leading to pulmonary hypertension.
What are the causes of the disorder?
A normal heart is divided into four chambers – two upper chambers known as atria (and separated from each other by the atrial septum) and two lower chambers known as ventricles (separated from each other by the ventricular septum). At birth, the two atria are connected through a small opening known as the foramen ovale, which gets sealed gradually with time through the formation of the atrial septum.
However, atrial septal defects occur if the atrial septum is not formed completely during foetal development or does not close the hole properly. Prolonged opening of the foramen ovale results in the excessive blood flow to the lungs and high blood pressure.
It is suggested that the disorder takes place at about five weeks of pregnancy when heart development generally takes place. Genetics and environmental factors are also thought to play a role in development of the disorder.
What one needs to know about symptoms or signs?
A person might not show any symptoms of ASD if s/he do not suffer from any other heart defect or have a small defect (less than 5 mm), or if the symptoms develop at around 30 years of age or later.
Commonly occurring symptoms of ASD include:
- Heart murmur (whooshing sound heard through a stethoscope)
- Shortness of breath
- Heart palpitations
- Swelling of feet, legs or abdomen
- Bluish skin colour
Which specialist should be consulted in case of any of the signs and symptoms?
A routine examination may detect abnormal heart sounds like a murmur, which is caused by turbulent flow of blood. A general practitioner will refer an affected person to a cardiologist for further investigation of the heart. Alternatively, the affected adult or their child may visit a cardiologist if they experience any of the symptoms listed above.
What are the screening tests and investigations done to confirm or rule out the disorder?
Based on the symptoms, physical examination and tests for the heart, the doctor will determine the size and severity of the atrial septal defect. Following tests may be conducted to diagnose ASD:
- Echocardiogram – Often the first test done for ASD, an electrocardiogram converts sound waves to video images of the heart. This allows the doctor to measure pumping strength of the heart chambers, valves and signs of heart defects.
- ECG – This method can identify heart rhythm problems by monitoring electrical activity of the heart.
- Cardiac catheterization – The doctor can check the heart’s pumping action and functioning of heart valves by inserting a catheter into a blood vessel in the groin or arm and guiding it to the heart.
- Coronary angiography – This method is used on patients aged 35 years or more. Blood flow through the heart’s arteries is determined using a special dye and x-rays.
Diagnosis during pregnancy
For pregnant women, foetal echocardiography will be conducted as part of routine antenatal examinations. An ultrasound scanner creates a picture of the baby’s heart, which is useful in identifying any congenital heart disease.
What treatment modalities are available for management of the disorder?
Treatment of ASD depends on the size of the hole in an adult or a child’s heart. Small defect may not require any treatment as these may close on its own during childhood. However, in cases of large septal defects, medication and surgery may be required.
- Medications – Medications do not treat the hole, but relieve some symptoms and reduce risk of complication post surgery. Patients may be prescribed medicines for keeping their heart beat regular (beta blockers and digioxin) or reducing the risk of blood clots (anticoagulants like warfarin and aspirin).
- Surgery – Surgical repair, for both children and adults, involves plugging the opening between the atria, through two methods:
- Cardiac catheterization – A plug or patch is guided through a catheter put in a blood vessel (groin) and placed at the site of the hole. Heart tissue grows around the mesh and seals it permanently.
- Open-heart surgery – Performed under general anaesthesia, the surgeon will stitch or use patches to seal the hole.
What are the known complications in management of the disorder?
Congenital heart diseases like ASD are prone to further problems like:
- Developmental issues in children – Delay in development, learning difficulty due to poor oxygen supply during early life that affects brain development.
- Respiratory tract infections
- Pulmonary hypertension
- Heart rhythm problem and heart failure
- Blood clots
- Sudden cardiac death
What precautions or steps are necessary to stay healthy and happy during the treatment?
If a patient suffers from other heart defects too, s/he may be prone to developing infective endocarditis (infection due to growth of bacteria on the surface of the heart). Antibiotics may be required before any surgical or dental procedures.
What are the dietary and physical activity requirements during the course of the treatment?
It is essential to keep one’s heart healthy by taking a diet rich in fruits, vegetables and whole grains, and avoiding cholesterol, saturated fats and sodium rich foods. Affected persons can discuss the permissible level of physical activity for their condition with their doctor.
Is there any risk to other family members of having the disorder?
Congenital heart defects run in families and may have a genetic linkage with disorders like the Down’s syndrome. The doctor can guide people about the chances of having children with a heart defect if they or their older children suffer from one. Further, a rubella infection and consumption of alcohol or drugs during pregnancy can harm the foetus and increase the risk of having a baby with ASD.
How can the disorder be prevented from happening or recurring?
It is not possible to prevent atrial septal defects but one can take precautions and guidance on immunity, current health condition and family medical history from a health care provider if planning a pregnancy in the near future.
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“Congenital heart disease,” NHS.UK, http://www.nhs.uk/Conditions/Congenital-heart-disease/Pages/Introduction.aspx
“Atrial Septal Defects,” WebMD.com, WebMD Medical Reference from the National Organization of Rare Disordershttp://www.webmd.com/heart-disease/atrial-septal-defects
“Atrial septal defect (ASD),” MedlinePlus, http://www.nlm.nih.gov/medlineplus/ency/article/000157.htm
“Atrial septal defect (ASD),” Mayoclinic.com, Mayo Clinic Staff, http://www.mayoclinic.com/health/atrial-septal-defect/DS00628