The hypothesis of this study is a nutrition preoperatively in infants and children undergoing elective cardiac surgery with cardiopulmonary bypass leads to improvement in nutritional status, intervention, and that this results in good postoperative results.

If this hypothesis is confirmed, there will be subsidies for systematic implementation of nutritional interventions in patients seen in service.

Inclusion Criteria:

• Patient with congenital heart disease requiring elective surgical correction;
• Age> 30 days and ≤ 5 years, with the aim of excluding the neonatal period, which are operated children with complex heart defects, and older children, where the time living with the disease damages the myocardium and the pulmonary circulation, leaving only children with fewer serious and, in general, are less subjected to complex surgery diseases.

Exclusion Criteria:

• Chronic gastrointestinal diseases (defects, malabsorption, celiac disease, inflammatory bowel disease, diabetes mellitus);
• Patients with other organic defects that may compromise the growth and / or nutritional status;
• Patients undergoing emergency surgery;
• Request of parents or guardians at any time;
• Patients receiving exclusive breastfeeding;
• Died during the study period;
• Patients using cardiac pacemaker or other electrical or electronic device that interferes with the reading of the electrical bioimpedance.