Participants in this group will receive echocardiogram imaging before cycles 1, 5, 9, and 13 of trastuzumab (or every 3 months) and another echocardiogram after completion of trastuzumab (within 100 days after completion of HER2-TT).

The Judicious Imaging Group will get split into two separate subgroups, intermediate-risk or low-risk, depending on their risk of heart failure, which will determine how many echocardiograms they will receive. The low-risk subgroup will get an echocardiogram once every 6 months (before cycles 1 and 9 and after the completion of trastuzumab). The intermediate-risk subgroup will get an echocardiogram approximately once every 4 months (before cycles 1, 6, and 12 and after completion of trastuzumab).

12-lead echocardiogram