Atrioventricular canal defect can involve only the two upper chambers of the heart or all four chambers. In both types, extra blood flows into the lungs. Symptoms depend on whether the defect is partial or complete. Complete defect The condition affects all of the heart's chambers. Symptoms of a complete atrioventricular canal defect usually develop in the first weeks of life. Symptoms are generally similar to those of heart failure. They may include: 
Blue or gray skin color due to low oxygen levels
Difficulty breathing or rapid breathing
Excessive sweating
Fatigue
Irregular or rapid heartbeat
Lack of appetite
Poor weight gain
Swelling in the legs, ankles and feet
Wheezing
 Partial defect The condition affects only the two upper heart chambers. Symptoms of a partial atrioventricular canal defect may not appear until early adulthood. The symptoms may be due to complications such as heart valve problems, high blood pressure in the lungs or heart failure. Symptoms may include: 
Fatigue and weakness
Nausea and lack of appetite
Persistent cough or wheezing
Rapid or irregular heartbeat, also called an arrhythmia
Reduced ability to exercise
Shortness of breath
Swelling in the legs, ankles and feet
Chest pressure or pain
