Atrial septal defect is a congenital heart defect wherein the wall that separates the upper chambers of the heart has a opening. Scroll down to find out more about the causes, symptoms and treatment of this medical condition.
The human heart is one of the most important organs of the circulatory system. It performs the vital function of pumping oxygenated blood to various parts of the body. A malfunctioning of the heart would therefore, have serious repercussions on one’s health. Though various types of heart diseases may occur due to poor lifestyle choices, a heart defect could also be congenital in nature.
An atrial septal defect (ASD) is one such congenital heart defect that is characterized by the presence of an opening in the septum. Septum refers to the muscular wall that partitions the heart into right and left side. An atrial septum is the muscular wall that separates the right atrium from the left atrium. This defect is bound to affect the flow of blood, and if the hole is quite large, one is most likely to experience a variety of distressing symptoms. Given below is some information on and how it can be treated.
Atrial Septal Defect
A fetus gets all the required nourishment from the mother, and develops in stages during the nine months. The human heart begins to develop in the third week and by the fourth week, the heart takes the form of a tube-like structure. By the sixth week, the heart even begins to pump blood. Since the lungs are not used for the exchange of oxygen and carbon dioxide yet, a small opening in the septum, helps in speeding up the flow of oxygenated blood that the fetus receives from the placenta. Thus, blood can bypass the lungs and the blood flow within the heart is facilitated with the help of this opening.
This opening is referred to as foramen ovale. This opening closes on its own at birth due to increased blood pressure on the left side of the heart. If the opening in the septum doesn’t close at this time, the child is diagnosed with patent foramen ovale. In common parlance, one may refer to it as a hole in the heart. If the hole is too small, this condition may not be symptomatic.
If this opening is large, blood would flow from the left atrium to the right atrium, and this may give rise to certain complications, especially later in life. It is believed that women who are exposed to certain harmful industrial chemicals during pregnancy, may give birth to a child with such a heart defect. Chromosomal defects, alcohol abuse, substance abuse or prolonged use of certain drugs also figure in the list of risk factors.
Before we move on to the symptoms of ASD, let’s understand how the heart works. The heart is divided into four chambers. As you already know, septum divides the heart into right and left side. The upper chambers are referred to as right atrium and left atrium, whereas the lower chambers are called right ventricle and left ventricle.
Once the deoxygenated blood from the veins moves into the right atrium, the tricuspid valve located between right atrium and right ventricle opens up, so as to allow the blood to move into the right ventricle. The blood is then pumped into the lungs. When the left atrium receives oxygenated blood from the lungs, mitral valve located between the left atrium and left ventricle opens, and blood passes into the left ventricle. This oxygen-rich blood is then circulated to the various parts of the body.
If an opening is present between the atrial septum, blood may bypass the lungs. If inadequately oxygenated blood travels to various parts of the body, one may become highly susceptible to cyanosis. Lack of oxygen supply to the brain could even make one susceptible to stroke or a brain attack. One could even suffer from congestive heart failure.
Heart murmurs or abnormal sounds from the heart could be caused by this congenital defect. The connection between ASD and murmurs may be attributed to the increased flow of blood into the lungs. Shortness of breath, respiratory problems and pulmonary hypertension may also result from pressure buildup due to irregular blood flow between the atria.
In a majority of cases, this condition may not be diagnosed until one suffers from a mini-stroke or other heart problem. A small perforation may not produce any symptoms, but a large hole can certainly cause problems. Chest X-ray or imaging procedures such as ECG, ultrasound or MRI are often conducted in order to diagnose this defect. Since a large hole in the septum can put a lot of burden on the heart as well as lungs, it’s essential that the perforation be repaired at the earliest through surgery. The surgery is performed under anesthesia, and an incision is made on the chest to get access to the heart.
The hole in the atrial septum can then be stitched and patched using a small piece of membrane. The incision is then sutured. A bypass machine is used until the defect is repaired. After the surgery, the heart-lung bypass machine is shut down. A surgical robotic system may even be used for correcting this defect. A specialized procedure called cardiac catheterization may also be used for correcting ASD.
Under this procedure, a catheter is inserted through the skin into a blood vessel in the leg and is moved until it reaches the heart. After the oxygen levels, blood flow as well as blood pressure are tested, a closure device is implanted over the hole to permanently seal the perforation in the atrial septum. The success rate of this surgery is high, and the heart tissue usually heals within six months.
Though this congenital defect may go unnoticed for a long time if the hole in the septum is small, a large perforation can pose serious health risks. If a child is born with this defect, it’s essential that this heart condition be monitored on a regular basis and the hole be repaired as per the advice of the cardiologist.