Evolution of Cardiopulmonary Fitness in Children With Congenital Heart Disease
Evolution of Cardiopulmonary Fitness in Children With Congenital Heart Disease
With an incidence of 0.8 %, congenital heart disease (CHD) is the leading cause of congenital
 anomalies at birth. Medical advances in CHD have transferred the mortality from childhood to
 adulthood and today there are more adults with CHD than children. After focusing on survival,
 more attention is being given to health-related quality of life and secondary prevention in
 this population where warning signals are launched on the risk of sedentary lifestyle,
 obesity, cardiovascular risk 1.

 The cardiopulmonary exercise test (CPET), which is a non-invasive and dynamic examination, is
 becoming the gold standard to the follow-up 2 of these patients by allowing to quantify
 disease severity, to evaluate the quality of life 3, to give important prognostic information
 on functional capacity and haemodynamic response 4, to facilitate a safe decision-making when
 prescribing exercise programmes and sport participation for these children with CHD 5.

 In this context, in a cross-sectional study from 2010 to 2015, the investigators evaluated
 the cardiopulmonary fitness of children with CHD by comparing them with healthy children 6.
 In this study, 496 children with CHD compared to 302 healthy children were included. It
 showed that maximum oxygen uptake (VO2max) and ventilatory anaerobic threshold (VAT) are
 decreased in CHD children compared to healthy children, clinical determinants of decreased
 VO2max have been defined for CHD children. This study was proposed, despite the
 cross-sectional nature, an average decrease in annual VO2max (0,84 ml/kg/min per year) to
 make pediatric and congenital cardiologist aware of the need to a regular follow up for these
 patients.

 In this new study, the main objective was to know the real evolution of VO2max in these
 patients from this same cohort, with a longitudinal design, by collecting a new CPET carried
 out between 2015 and 2020 and compared these results to healthy pediatric population.

 The secondary objectives were: to know the evolution of the VAT, to define the clinical
 determinants in relation to the annual decrease of the VO2max. And to describe the population
 lost to follow-up in this retrospective study which represents current practice.
Longitudinal multi-center study from November 2010 to September 2020 in two pediatric CPET
 laboratories (center 1: M3C Regional Pediatric and Congenital Cardiology Centre, Montpellier
 University Hospital, France; center 2: Pediatric Cardiology and Rehabilitation Centre,
 Institut-Saint-Pierre, Palavas-Les-Flots, France).

 Two groups will be identify: CHD group and control group. The CHD group is made up of the
 children included in the first study6. From these 496 children with CHD, children with a
 second CPET more than one year from the first referral CPET were included. If several CPETs
 were performed in the follow-up, we retain the most distant CPET from the first. The patients
 included in the initial study were aged 5-18 years old and they were referred by their
 paediatric cardiologists to one of the two CPET laboratories after their annual medical
 check-up.

 The control group consisted of children referred for a nonsevere functional symptom linked to
 exercise (murmur, palpitation or dyspnoea) or for a medical sports certificate. These
 children were classified in the control group only after a completely normal check-up,
 including physical examination, ECG, echocardiography and spirometry. Children with any
 chronic disease, medical condition (cardiac, neurological, respiratory, muscular or renal),
 or medical treatment and those requiring any further specialised medical consultation were
 not eligible. We included controlled children from 2015-2020 period who will be added to the
 controlled patients of the initial study6. These patients only had one CPET.

 The main objective was to describe the annual evolution in VO2max for patients with CHD
 compared to control children.

 Secondary obectives were :

 -  describe the annual evolution of ventilatory anaerobic threshold (VAT) for patients with
 CHD compared to control children.

 -  define the clinical determinants in relation to the annual decrease of the VO2 max.

 -  describe the population lost to follow-up in this retrospective study which represents
 current practice
Inclusion criteria for CHD group :

 - children with CHD included in the first study carried out from 2010 to 2015 6 and who
 have had at least 1 CPET 1 year after the first.

 Inclusion criteria for control group :

 -  children referred for a nonsevere functional symptom linked to exercise (murmur,
 palpitation or dyspnoea) or for a medical sports certificate.

 -  completely normal check-up, including physical examination, ECG, echocardiography and
 spirometry.

 Exclusion criteria for control group:

 -  Children with any chronic disease, medical condition (cardiac, neurological,
 respiratory, muscular or renal)

 -  Children with any medical treatment

 -  Children requiring any further specialised medical consultation