Atrial Septal Defect: Genetic Deformity

Atrial Septal Defect is characterized by an opening in the atrial septum, the wall that divides the upper right and left heart chambers. This defect has been noted, in one study, as effecting African Americans and Caucasian alike, but Native Americans are among the highest groups. Of course, these statistics have been questioned, by other studies that showed that Caucasians are less commonly effected by Atrial Septal Defect than any other race or ethnicity.

Correlated Birth Defects

This birth defect has been noted in newborns that have been diagnosed with other correlated birth defects.

  • Down Syndrome (Trisomy 13, 18, 21)
  • Fetal Alcohol Syndrome
  • DiGeorge Syndrome (immunodeficiency disease)
  • Velocardiofacial Syndrome (abnormality of the pharyngeal arch)

Other cardiac birth defects have also been noted, in conjunction with Atrial Septal Defect.

Categories and Types

  • Type I –  also known as Ostium Primum Septal Defect, which shows a deformity in the endocardial cushion section (ventricular and atrioventricular canal). This type is correlated with a cleft in one leaflet of the mitrial valve. 
  • Type II – also known as Secundum Atrial Septal Defect, which shows a deformity in the fossa ovalis (mideal section of the atrial septum). This is the most common type.
  • Sinus Venous is a defect in the inferior superior vena cava, where the right pulmonary veins enter the heart. This causes an abnormality in the way the blood drains from pulmonary veins, instead of draining into the left atrium, which is normal, the blood drains into the right atrium.
  • Coronary Sinus is a defect in the coronary sinus, which is the rarest form of Atrial Septal Defect.

Ventricular Septal Defect involves a hole or defect in lower portion of the septum.

Etiology

During the fetal development the heart, which begins in the embryonic period (begins at week 5 and ends at week 10) . The development of the heart starts out as a hollow tube, then extends out forming the walls or septa, which separates the right and left sides of the heart. The defect occurs, when the barrier does not close completely.

Genetic factors have also been linked to this congenital defect, but most cases have been noted, as having no genuine cause for their maturation.

Genetic Testing

Mutations in the NKX2-5 gene has been linked to Atrial Septal Defect7, it can be diagnosed with genetic testing.

Diagnostic Testing

While many children with this defect do not exhibit any symptoms, others may be plagued with innumerable symptoms. When the parent begins to notice their child having difficulty breathing, during activities. A cardiologist will order several diagnostic tests that are beneficial.

  • Electrocardiogram
  • Echocardiogram
  • Cardiac Catheterization
  • Chest X-ray

If the child does not present with any symptoms, it may take may years, before the symptoms will begin to appear. In this case a diagnosis will not be explored, until the symptoms begin to present themselves.

Dangers

Life threatening dangers may be inevitable, since the risk for heart rhythm disturbances are extremely high, but with the pacemaker implantation the individual will have a good prognosis. Heart failure may occur, if medical treatment is not provided.

 Symptoms

  • Fatigues during activities
  • Tachypnea (rapid breathing)
  • Dyspnea (shortness of breath)
  • Growth development may be altered
  • Frequent respiratory infections (strep, influenza, colds, whooping cough)
  • Arrhythmia (abnormal heart beat)
  • Murmurs
  • Stroke
  • Hypertension (high blood pressure)

These symptoms are caused by the defect, which allows oxygen rich and oxygen poor blood to mix. This in turn causes only a portion of the oxygen rich blood to be pumped back into the lungs, instead of out of the body. The right portion of the heart will have to work much harder to suffice the lungs, with enough oxygen rich blood.

Treatments

Many cardiologist may wait to see if the defect repairs itself, by closing on its own. In the cases that this does not occur, before the beginning of the child’s school years, the decision to perform surgery may be in question. This will artificially close the defect, but this will be based on how large the defect.

  • Medication management may include diuretics (Lasix), which will aid the kidneys in riding the body of excess fluids.
  • Cardiac implant closure device is possible through the cardiac catheterization procedure.