Max Mitchell, M.D., a congenital cardiac surgeon,and Kathryn Collins, M.D., a pediatric cardiologist specializing in electrophysiology, reviewed the child’s history to determine her next treatment steps. Atbirth, her tricuspid valve that normally controls blood flow from the right atrium to the right ventricle was not formed, preventing blue blood from getting to her right ventricle and out to her lungs. The main pulmonary artery was also too small to provide adequate blood supply to her lungs. A hole between the right and left atria, known as an atrial septaldefect, allowed a mix of oxygen-rich and oxygen-poor blood to be pumped through her body. To address these issues and enable the child to grow, a shunt had been placed in her as a neonate between the pulmonary artery and the aorta allowing blood to get to the lungs. And at 12 months of age, she underwent a bi-directional Glenn procedure, the first in a two-stage surgical strategy that by passes the heart entirely and pumps blood returning from the tissues directly to the lungs. After the Glenn procedure, Dr. Mitchell and his colleagues determined that the child was a candidate for the next stage of surgery known as the Fontan procedure, the second in the two-stage surgery.
However, a successful Fontan procedure is highly dependent on a normal heart rhythm and heart rate.The arrhythmia associated with WPW syndromehad to be addressed either prior to surgery in the catheterization lab or at the time of surgery. In addition, it was imperative that her accessory electrical pathway be ablated prior to completionof the surgery because it would be impossible to address in a catheterization laboratory after the Fontan procedure, and because all the venous connections from her body to her heart would no longer exist. This would leave no route to get a catheter to the accessory pathway. Dr. Collins attempted to ablate the accessory pathway in the catheterization laboratory but was unable to contact the accessory pathway due to the markedly abnormal anatomy. As a result, she approached Dr.Mitchell to gauge the feasibility of a surgical ablation at the time of the planned Fontan operation.