A hole in the heart atrial septal defect is a hole in the wall between the atria (the upper chambers of the heart). This hole allows blood to flow from the left atrium to the right atrium. The blood then mixes with oxygen-rich blood in the right ventricle and is pumped out to the body. The size of the hole in the atrial septal defect determines how much blood flows from the left atrium to the What are the symptoms of an Atrial Septal Defect? An atrial septal defect (ASD is a hole in the wall separating the upper chambers of the heart The symptoms of an ASD depend on how big the hole is and where it's located A small ASD may not cause any symptoms, while a large ASD can cause shortness of breath, fatigue, and irregular heartbeat ASDs are usually caused by a combination of genetic and environmental factors Most ASDs can be successfully treated with surgery or medications What causes an Atrial Septal Defect? An atrial septal defect (ASD is a hole in the wall between the upper chambers...