This randomized phase IIb trial studies how well low-dose carvedilol works in preventing heart failure in cancer survivors exposed to high dose anthracyclines for management of childhood cancer. Patients who received high-dose anthracycline chemotherapy are at a much greater risk for developing heart failure compared to survivors who didn't get any anthracycline chemotherapy. Heart failure happens when the heart muscle has been weakened and can't pump blood as well as it should. Carvedilol may help lower the risk of cardiovascular complications.