Abstract
Cardiopulmonary exercise tests (CPET) focusing on analyses of heart rate (HR) responses and chronotropic incompetence (CI) could provide early information about treatment’s negative cardiac effects. We examined childhood acute lymphoblastic leukemia (ALL) survivors’ HR response during maximal CPET and identified survivors with CI. A total of 250 childhood ALL survivors underwent a CPET on ergocycle to assess their HR response. We used a multiparametric structure of three methods to assess survivors’ CI, as follows: 1) age-predicted HRmax (APMHR): failure to achieve 85% of the APMHR at the peak of CPET; 2) HR reserve (HRR): failure to achieve 80% of the HRR at the peak of CPET; and 3) metabolic chronotropic relationship (MCR): failure to reach an MCR slope ratio >0.8 at each stage of the CPET. Among 250 childhood ALL survivors, 216 survivors performed a maximum CPET. We observed that 73 males and 74 females did not achieve their predicted HRmax. We found that 6 survivors did not achieve 85% of their APMHR (80.9 ± 3.9%) and had an MCR below 80% (53.9 ± 13.8%). In addition, 16 survivors did not achieve 80% of their HRR (71.0 ± 7.4%) and among them, 15 survivors had an MCR below 80% (61.0 ± 12.1%). Survivors with CI had a significantly lower cardiorespiratory fitness than those without CI. This study shows that survivors are at risk of developing altered HR responses and CI many years after the end of their cancer treatments. These findings highlight the importance of early detection of cardiac damage due to cancer treatments.
Acknowledgements
We appreciate the assistance of Ariane Levesque (McGill University) and Audrey Harvey (Université de Montréal) for their review of the article in the English language.
Declaration of conflicting interests
The authors report no conflicts of interest.
Data availability statement
Our data are not deposited in publicly available repositories. However, the datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.