When kids get a new heart through a transplant, their bodies might try to reject it. To check for this, doctors often use a test called a biopsy, which can be scary, risky, and costly. This study wants to see if we can use something called cardiac magnetic resonance imaging (CMR) and blood tests to find out about rejection without needing a biopsy. CMR is a special type of scan that takes pictures of the heart, while blood tests look for changes that might show rejection. This could make things easier and safer for kids with new hearts.

• Study uses non-invasive methods like CMR and blood tests to detect heart rejection.
• Participants need to be between 6 and 25 years old and have had a heart transplant.
• This study might help reduce the need for risky biopsies in the future.