This study aims to more accurately assess cardiac function, ventilation and exercise capacity in a non-invasive fashion, and to better characterize exercise intolerance in the setting of three populations of individuals with chronic diseases of childhood (acute lymphoblastic leukemia (ALL), chronic lung disease (CLD) of prematurity, and post-heart transplant (HT))
Acute lymphoblastic leukemia survivor, OR living with chronic lung disease of prematurity, OR living with heart transplant
8-25 years old
Height: ≥ 48 inches
Ambulatory without assistance
ALL specific: received cranial radiation, bone marrow transplant recipients
Investigator or patient's primary physician deems the patient unsuitable for the study
History of malignancy, CLD or HT or any other diagnosis which may reduce cardiorespiratory function
Investigator deems the patient unsuitable for the study