Atrioventricular septal defect natural history

Natural history
The true natural history of an atrioventricular septal defect is difficult to definitively determine. No record exists to detail the course of disease of an untreated complete atrioventricular septal defect. In patients with a moderate case of a partial or incomplete atrioventricular septal defect, patients may be asymptomatic in the first decade of life. During adolescence, left-to-right shunting and atrial arrhythmia may present. As continued development occurs in these patients, sinus node dysfunction may develop and can lead to exercise intolerance. More severe cases of partial or incomplete atrioventricular septal defects left untreated can lead to morbidity in infancy and early childhood.

In general, long-term survival of patients with all types of atrioventricular septal defects had an overall poor prognosis. Mortality was higher in complex atrioventricular septal defect cases. Approximately 80% of patients with a complete AVSD died by age 2. Other studies have observed a trend between survival in the first year of life and complexity of defect. In one study, 54% of infants with a complete atrioventricular septal defect survived the first 6 months, 35% survived into one year of life, and only 4% survived 5 years of life.

There is no evidence to suggest that the association between atrioventricular septal defects and Down syndrome correlates to equally grim outcomes. One study documented only 4 late deaths over a 27-year period in patients greater than 1 year of age with un-operated defects.

Complications
Common complications from atrioventricular septal defect include:
 * Congestive heart failure
 * Pulmonary vascular obstructive disease/Eisenmenger syndrome
 * Tachypnea
 * Cyanosis
 * Failure to thrive
 * Sinus node dysfunction
 * Hypertension in the lungs
 * Irreversible damage to the lungs

Prognosis
When treated with surgical repair, patients with atrioventricular septal defect have a minimal long-term morbidity. Complete atrioventricular septal defect repair is 3.6% and the 10-year survival rate is 81%. Some patients may live the first few years of their life without surgical intervention. The surgical survival rate for pediatric complete atrioventricular septal defect is 94% with an overall survival rate of 91% of patients repaired between 4-6 months of age.