Atrial septal defect (ASD) is known as a congenital heart defect the location where the wall that separates the top heart chambers (atria) does not close totally. Congenital suggests the defect exists at beginning.
In fetal blood circulation, there's an opening in between the two atria (the upper chambers of the heart) allowing blood to bypass the respiratory system. This opening most often ends around the time the baby is delivered.

If the ASD is continual, blood is constantly flow from the left to the right atria. This is called a shunt. If a lot of blood moves to the right side of the heart, pressures in the lungs build-up. The shunt are usually reversed so that blood flows from right to left. Small atrial septal defects usually cause hardly any troubles and could be found much later in life. Many issues can occur if the shunt is large, however. In advanced and severe situations with large shunts the elevated pressure on the right side of the heart would end in turnaround of blood flow (now from right to left). This usually results in important shortness of breath.
In the course of normal growth and development of the fetal heart, it comes with an opening up in the wall (septum) isolating the left and right upper compartments of the heart. Commonly, the opening closes just before birth, but if it does not, the child is given birth to with a hole between the left and right atria. This abnormal opening is called an atrial septal defect and causes blood from the left atrium to flow (or "shunt") through the hole into the right atrium.

Differing kinds of atrial septal defects occur, and they can be categorised according to where in the separating wall these are discovered. The most normally found atrial septal defect, called secundum atrial septal defect, happens in the middle of the atrial septum and accounts for about 70 percent of all atrial septal defects.

Unnatural openings also form in the upper part of the atrial septum (called sinus venosus ASD) the location where the superior vena cava and right atrium join, and lower parts of the atrial septum (called primum ASD). A sinus venosus ASD usually requires the right upper pulmonary vein, while a primum ASD normally occurs together with an abnormality in the mitral valve and/or tricuspid valve, and leads to some blood leakage (regurgitation) back through the valves.

Atrial septal defects may appear by itself or in conjunction with other congenital heart problems, such as ventricular septal defect. They can be no more than a pinpoint or as large as the area where the entire septum ought to be situated.
Reasons

Abnormal openings in the atrial septum arise during fetal development. These irregularities will go undetected if the opening is small and makes no abnormal signs and symptoms. If the defect is large, oxygen-rich blood from the left atrium flows back to the right atrium and gets pumped back to the respiratory system again, creating more work for the heart and lungs. The right atrium may get bigger or enlarge to hold the extra blood.

In certain cases, an atrial septal defect can allow blood clots from the body to enter the brain and result in a stroke . Without treatment atrial septal defect can bring about pulmonary hypertension , chest infection, Eisenmenger's syndrome, atrial fibrillation, atrial flutter, stroke, or right-sided heart failure.

Symptoms

Somebody born with the atrial septal defect can have no symptoms in childhood, and the situation may go undetected into adulthood. Stunted growth may be a symptom of atrial septal defect. Various other signs that might develop over time include things like:

difficulty breathing
fainting
irregular heart beats or palpitations (abnormal heart beats that seem like fluttering in the chest)
inability to exercise without becoming over-tired
difficulty breathing with exercise or activity
Therapy
Twenty percent of atrial septal defects in children fix by themselves without treatments as soon as a child is two years older. If the opening fails to close on its own, it needs to be repaired to stop the pulmonary arteries from becoming thickened and blocked due to increased blood flow. If this condition (pulmonary vascular obstructive disease) remains without treatment, it could increase the risk of death by Twenty five %.