1990: Radio waves directed through a catheter correct a cardiac rhythm disorder called Wolff-Parkinson-White syndrome, marking the first pediatric non-surgical repair of a cardiac arrhythmia.

1996: Kathy Jenkins, MD, and James Lock, MD, develop the Webster-Jenkins basket catheter to provide rapid diagnostic information in mapping multiple sites of cardiac arrhythmias.

1999: The FDA approves the use of the CardioSEAL, a minimally invasive device developed at Children's to repair holes in the hearts of the most seriously ill heart patients. The device is implanted with a cardiac catheter.

1999: Simon Hoerstrup, MD, grows replacement heart valves from the cells of sheep, an advance expected to lead to more durable valves than the mechanical and animal valves used today.

2001: Children's Hospital Boston clinicians care for a hemophiliac patient with life-threatening heart disease, making him the world's first hemophiliac to be placed on extracorporeal membrane oxygenation, (ECMO) and only the second to undergo a heart transplant.

2001: Children's Hospital Boston performs the world's first successful fetal repair of hypoplastic left heart syndrome (HLHS) in a 19-week-old fetus, threading a cardiac catheter through the fetus's atrial valve and inflating a balloon to widen the opening.

2002: Laboratory Medicine investigator Nader Rifai, MD, co-authors a landmark study likely to alter federal guidelines for cardiovascular disease detection, showing that a simple and inexpensive blood test for C-reactive protein (CRP) - a substance produced in the liver when arteries become inflamed - is a more powerful predictor of a person's risk of suffering a heart attack or stroke than screening based on LDL cholesterol.

2002: HHMI investigator Mark Keating, MD, shows for the first time that zebrafish can regenerate heart muscle within two months after a severe injury. His team also identifies a possible genetic and molecular model for regeneration in zebrafish which could help direct further research that would benefit millions of people who suffer heart attacks or experience other forms of cardiac injury.

2002: Children's Hospital Boston is the first pediatric center to obtain a surgical robotic system. The first procedures were performed in March 2002; since then the Department of Cardiac Surgery has carried out many robotic-assisted operations.

2002: Children's Hospital Boston is the first to perform robot-assisted surgery to correct a Patent Ductus Arteriosus (PDA), a blood vessel present in fetal life that does not close properly, resulting in excess blood to the lungs.

2003: Children's Hospital Boston continues to perform fetal intervention to treat congenital heart defects. Since the hospital's first attempt in March 2000, the Cardiovascular Program's Fetal Program has performed 15 fetal interventions, including 11 aortic valve balloon dilations, creation of three atrial septal defects and one pulmonary valve dilation.

2003: Since the inception of the Heart Transplant Program in 1986, Children's cardiac surgeons have performed more than 150 heart transplants, making it one of the largest pediatric heart transplant programs in the country.