EXERCISE TESTING IN PEDIATRIC HEART, HEART-LUNG, AND LUNG-TRANSPLANT RECIPIENTS

Cardiorespiratory responses to progressive exercise were examined in 3 8 children who had undergone heart (n = 16), heart-lung (n = 13), or d ouble-lung (n = 9) transplantation, and in 41 healthy controls. The fo ur groups were similar in age, but the control subjects and heart tran splant recipients were significantly larger than the heart-lung and lu ng recipients as assessed by body mass index (BMI). Time since transpl ant was significantly longer in the heart (601 days) compared with hea rt-lung (146 days) and lung (125 days) transplant groups. Physical wor k capacity and peak oxygen uptake were significantly reduced (43 to 64 % of predicted) in the three transplant groups compared with the contr ol group. Peak heart rate (percent predicted) was significantly higher in the control subjects (94%) compared with the heart (66%), heart-lu ng (70%), and lung (77%) transplant recipients. Peak minute ventilatio n was significantly higher in the control (72.9 L/min) and heart trans plant (51.0 L/min) groups than the heart-lung (37.4 L/min) and lung (4 1.3 L/min) transplant groups. The control group had a higher peak tida l volume than the three transplant groups, and a higher peak respirato ry rate than the lung transplant recipients. Correlational analysis re vealed that physical work capacity (PWC) was significantly related to heart rate at peak exercise (HRpeak) and minute ventilation at peak ex ercise (VEpeak) in the heart transplant recipients, BMI, VEpeak, and F EV(1) in the heart-lung transplant recipients, and BMI, HRpeak, VEpeak , FEV(1), and number of days posttransplant in the lung transplant rec ipients. In addition to these variables, physical deconditioning and f actors related to pharmacotherapy, infection, and rejection may also c ontribute to the decreased PWC observed in the transplant recipients.