At the University of Chicago Medicine Comer Children's Hospital, we provide the most advanced treatment options for infants, children and teens suffering from heart failure. Congestive heart failure occurs when the heart muscle is unable to deliver enough nutrient-rich blood to meet the body’s need for oxygen. In babies and young children, this may happen when a valve defect allows too much blood to pass through the lungs, overwhelming the body. In older children and teens, heart failure often results from a weakened or damaged heart muscle. During heart failure, the heart keeps pumping, but not as efficiently.