XVIVO Heart Box (XHB) With Supplemented XVIVO Heart Solution (SXHS) Continued Access Protocol (CAP)

This study is evaluating a device called the XVIVO Heart Box, which is used to keep a donor heart alive and healthy outside the body during transport to a transplant recipient. It uses a special preservation solution to maintain the heart in better condition before surgery. The goal is to continue providing access to this technology while additional safety and effectiveness data are collected. **You may be eligible if...** - You are 18 years or older - You are listed and waiting for a heart transplant - You have signed an informed consent form **You may NOT be eligible if...** - You have previously had a solid organ or bone marrow transplant - You need a transplant of multiple organs at the same time - You are currently enrolled in another investigational study - The donor heart does not meet certain standard criteria (such as age limits or donation after cardiac death criteria) Talk to your doctor to see if this trial is right for you.