An atrial spetal defect, also called interauricular communication, is some sort of physical communication of blood between the two upper chambers of the heart (the atria) that should not be there. It happens more often in girls. There are four types of these defects, coronary sinus defect being the least common. The heart delivers blood to itself through a special vessel called the coronary artery, and the blood then comes back to the heart through the coronary sinus. Atrial septal defect of the coronary sinus is a diversion of blood at the mouth of the coronary sinus due to absence of the walls that usually separate the sinus from the left atrium. Children with the defect usually have rapid breathing, shortness of breath, fatigue, sweating, palpitations, frequent respiratory infections, and poor growth. At about 30-40 years of age, other symtpoms like infections and heart failure may occur, so the defect should be closely monitored. Usually the cause is a random and not genetic, but a third of children also have a genetic disorder like Down's syndrome, characterized by intellectual disability, peculiar facial features, and growth delays. A physical examination may be enough to diagnose this defect, but sometimes a chest x-ray or echocardiogram are necessary. In an echocardiogram, high frequency sounds called ultrasounds are sent into the tissues of the heart and as they reflect back to the echo machine, they give the physician a visual picture of the heart. Sometimes medication can be used to close the opening, however open heart surgery may be necessary to close the hole is required if the patient has severe symptoms.