Although cardiopulmonary bypass (heart-lung machine) is a necessary component of heart surgery, it is not without consequences. Cardiopulmonary bypass initiates a potent inflammatory response secondary to the body's recognition of the abnormal environment of the heart-lung machine. This inflammatory response may lead to poor heart, lung and kidney function after the heart surgery. This is turn can lead to longer times on the ventilator (breathing machine), the need for higher doses of heart medications, a longer stay in the intensive care unit and even death. This is particularly true in infants less than one month of age due to their size and the immaturity of their organs. The appreciation of the post-cardiopulmonary bypass inflammatory response has resulted in a number of interventions directed at its reduction. No therapy has been recognized as the standard of care; however steroid therapy has been applied most often despite unclear evidence of a benefit. This study aims to determine if steroids improve the outcomes of babies undergoing heart surgery.