Single ventricle defects are birth defects that affect one of the heart’s ventricle chambers. The heart consists of four chambers, and the ventricle chambers are the lower chambers through which blood flows out of the heart. The affected chamber might be smaller, underdeveloped, or missing a valve. One out of 5 every 100,000 newborns are affected by this condition, and males and females are affected equally. Symptoms include: blue coloring of the skin, lips, and nails, rapid or labored breathing, rapid heart rate, and cold or clammy skin. They can be diagnosed using various medical tests such as: chest x-rays, electrocardiograms (EKG), cardiac ultrasounds, cardiac catheterization, or cardiac MRIs. Single ventricle defects are some of the most complex heart defects, and almost always require surgery to repair.