Open Access
ARTICLE
Chronotropic Response and Pulmonary Function are Associated with Exercise Performance in Children and Adolescents with Repaired Tetralogy of Fallot Independent of Cardiac Function
Shivani M. Bhatt1,*, Michael L. O’Byrne2, Michael McBride2, Stephen M. Paridon2, Elizabeth Goldmuntz2, Laura Mercer-Rosa2
1 Children’s National Hospital, Washington DC, USA
2 Children’s Hospital of Philadelphia, Philadelphia, USA
* Corresponding Author: Shivani M. Bhatt. Email:
Congenital Heart Disease 2020, 15(2), 101-115. https://doi.org/10.32604/CHD.2020.011287
Received 29 May 2020; Accepted 19 June 2020; Issue published 23 June 2020
Abstract
Objective: The determinants of exercise capacity in repaired tetralogy of
Fallot (rTOF) are multifactorial and remain incompletely understood. This study
sought to evaluate the association of chronotropic response with exercise parameters
and investigate the determinants of heart rate reserve (HRR) in a cohort of children
and adolescents with rTOF.
Design: We retrospectively analyzed patients with
rTOF, age 8–18 years, who underwent cardiac magnetic resonance (CMR) and
cardiopulmonary exercise test (CPET) for research purposes. Linear regression
models were performed to test associations among clinical, CMR and CPET
parameters. Outcomes included percent-predicted maximum VO
2 (%mVO
2) and
HRR.
Results: A total of 148 patients were included (mean age 12.3 ± 3.1 years).
The majority of patients had TOF with pulmonary stenosis (80%) and underwent
transannular patch TOF repair (78%). Median age at surgical repair was 4.2 months
(IQR 1.2, 8.4). There was preserved RV ejection fraction (60.4 ± 8.3%) and
moderate pulmonary insufficiency (regurgitant fraction 35.2 ± 16.6 %). On
CPET, %mVO
2 was overall diminished (76.5 ± 17.9 %), and % predicted forced
vital capacity (FVC) was diminished on spirometry. HRR, FVC and ability to reach
maximum effort were independently associated with greater %mVO
2. FVC, net
forward flow in the main pulmonary artery/m
2
, and reaching maximum effort were
associated with greater HRR, independently of RV volume, degree of PI and RV
ejection fraction.
Conclusions: In patients with rTOF, HRR and pulmonary function
(FVC) are more important contributors to exercise performance than right
ventricular function. Interventions to improve chronotropic health and pulmonary
function should be explored.
Keywords
Cite This Article
Bhatt, S. M., O’Byrne, M. L., McBride, M., Paridon, S. M., Goldmuntz, E. et al. (2020). Chronotropic Response and Pulmonary Function are Associated with Exercise Performance in Children and Adolescents with Repaired Tetralogy of Fallot Independent of Cardiac Function.
Congenital Heart Disease, 15(2), 101–115. https://doi.org/10.32604/CHD.2020.011287