Recovery kinetics of heart rate and oxygen uptake in long-term survivors of acute leukemia in childhood.

Analysis of the recovery period following physical exercise has gained importance in evaluating cardiopulmonary capacity, not only in athletes but also in patients with proven or suspected heart failure. The purpose of this study was to apply these methods to long-term survivors of acute lymphoblastic leukemia (ALL) in childhood, who are at risk of developing anthracycline-induced cardiomyopathy. Nine children (mean age 12 years) and 10 adults (mean age 24 years) were included in the study after treatment for childhood ALL. Recovery of oxygen uptake and heart rate following maximal spiroergometric exercise was compared to that in 29 trained and untrained age-matched controls. The change in oxygen uptake (DeltaVO2) and heart rate (DeltaHR) between maximal effort and 60 s of recovery did not differ significantly, either between children after oncological therapy (DeltaVO2: 14.95 ml/kg, DeltaHR: 35 bpm) and healthy children (DeltaVO2: 15.85 ml/kg, DeltaHR: 37 bpm), or between adult former oncological patients (DeltaVO2: 13.1 ml/kg, DeltaHR: 27 bpm) and untrained adults (DeltaVO2: 15.7 ml/kg, DeltaHR: 31 bpm). There was, however, a significant difference in DeltaVO2 between trained adults (DeltaVO2: 24.5 ml/kg) and both untrained adult controls (DeltaVO2: 15.7 ml/kg, p=0.004) and adult patients (DeltaVO2: 13.1 ml/kg, p=0.0002). This difference was not detected for heart rate. In conclusion, the recovery period did not reveal a discernible difference in cardiopulmonary capacity between former ALL patients and untrained age-matched controls. We did confirm that heart rate and oxygen uptake recovery serve as indicators of physical fitness.