I have had difficult times finding this info. The only source I have found is from Child Magazine, who puts out listings every other year. I do not know how scientific it is, but I will paste the info below.
2005: <http://www.child.com/kids/health_nutrition/top_hospitals04.jsp>
CARDIAC CARE
1. The Children's Hospital of Philadelphia
Its heart center, the largest inpatient pediatric cardiac facility in the country, received more than $7 million in government research funding in 2003 -- the most of any children's hospital in our survey. A state-of-the-art cardiac intensive care unit opened last year.
2. Children's Hospital Boston
Performing more than 2,500 cardiac operations and procedures on kids each year, the most in the U.S., the hospital has pioneered techniques for correcting heart problems while babies are still in the womb.
3. Texas Children's Hospital
Its doctors have made important discoveries about the underlying genetic causes of heart disease in kids and adults, which help determine children at risk for the condition and identify better medications to treat it.
4. Children's Healthcare of Atlanta
Despite treating tough cases, the hospital has less than a 2% mortality rate for cardiac surgery, one of the lowest in our survey. The facility offers one of the largest pediatric heart transplant programs in the U.S.
5. Children's Hospital of Wisconsin
Last year, the hospital became only one of a handful of pediatric centers to successfully repair ventricular septal defects -- the most common congenital heart defect, in which one or more holes are present in the muscular wall that separates the right and left ventricles -- in the catheterization lab rather than opening up the heart for surgery.
2003: <http://www.child.com/kids/health_nutrition/top_hospitals03.jsp>
Top Hospitals for Pediatric Cardiology
1. The Children's Hospital of Philadelphia. With nearly 10,000 admissions and consultations and $10 million in cardiac research funding, it was first to develop the balloon catheter for the repair of heart defects.
2. Children's Hospital Boston. It boasts a low mortality rate for cardiac surgery -- just 1.6%, despite treating some of the toughest cases.
3. Texas Children's Hospital. Doctors have developed a tool to diagnose inflammation of heart muscle tissue and have mapped the genes that cause several cardiac defects.
4. Children's Healthcare of Atlanta. It leads the nation in pediatric heart transplants, boasting an 80% one-year survival rate.
5. C.S. Mott Children's Hospital. Its heart disease prevention clinic for kids focuses on ways to combat high cholesterol, high blood pressure, and obesity.
