For much of the last year, Riley Stearns was No. 1 on the pediatric heart transplant list for his blood type as he walked the halls of the intensive care unit of the University of Minnesota Amplatz Children's Hospital. His mother, Peggy Zappa, pushed a ventricular assist machine, known as a Berlin heart, that kept his weakened heart pumping as he battled with dilated cardiomyopathy. Riley turned 4 last month, still hooked to the machine, but surrounded by family, friends and nurses who all came to love his extraordinary patience, endearing smile and stylish Mohawk hairdo. Riley never left the hospital. He died earlier this month when, according to his family, one of the machine's tubes ruptured. Riley's pediatric cardiac surgeon, Dr. James St. Louis, said his case underscores the need to heighten awareness of heart transplant donation in children. At his funeral, Riley's mom said "this is a happy day," because Riley could finally run free.