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Cardio-pulmonary exercise test (CPET) is becoming a key examination to assess physical capacity and disease severity in paediatric cardiology. The VE/VCO 2 slope has been increasingly used as a surrogate marker for morbidity and mortality in adult heart failure, pulmonary arterial hypertension and for adult patients with CHD. Nevertheless, the use of the VE/VCO 2 slope in children remains limited in the absence of reference values and clearly identified clinical determinants. This study aimed to compare the VE/VCO 2 slope in a paediatric cohort with CHD to that of age- and gender-adjusted healthy controls. We also intended to identify the clinical and CPET variables associated with VE/VCO 2 slope in this population. This cross-sectional study was carried out between November 2010 and September 2015 in two tertiary care paediatric cardiology reference centres. A total of 700 children were enrolled (399 CHD and 301 healthy controls). The mean VE/VCO 2 slope was significantly higher in CHD than in controls (31.6 ± 4.8 vs. 29.3 ± 4.8; P < 0.001). When considering CHD sub-groups, the VE/VCO 2 slope was impaired in single ventricle, complex anomalies of ventriculo-arterial connections, anomalies of the atrioventricular junctions and valves. The VE/VCO 2 slope according to the CHD physiological status was illustrated in the Fig. 1, it was higher in children with significant pulmonary regurgitation, tricuspid regurgitation, right ventricular hypertension and right ventricle outflow tract (RVOT) obstacle. In the CHD group, VE/VCO 2 slope increase was associated with BMI, the presence of a RVOT obstacle, the number of cardiac catheter procedures, as well as low age, FVC, tidal volume, and PetCO2 (Fig. 1). Increased VE/VCO 2 slope was predominantly in children with single ventricle and/or residual right heart abnormalities suggesting that maldistribution of pulmonary blood flow during exercise is an important CHD-unique determinant of VE/VCO 2 slope. [ABSTRACT FROM AUTHOR]

Background: Patient-ventilator asynchrony is common during noninvasive ventilation (NIV) with pressure support ventilation (PSV). We examined the effect of neurally adjusted ventilatory assist (NAVA) delivered through a facemask on synchronization in patients with acute respiratory failure (ARF).Methods: This was a prospective, physiologic, crossover study of 13 patients with ARF (median Pa(O(2))/F(IO(2)), 196 [interquartile range (IQR), 142-225]) given two 30-min trials of NIV with PSV and NAVA in random order. Diaphragm electrical activity (EAdi), neural inspiratory time (T(In)), trigger delay (Td), asynchrony index (AI), arterial blood gas levels, and patient discomfort were recorded.Results: There were significantly fewer asynchrony events during NAVA than during PSV (10 [IQR, 5-14] events vs 17 [IQR, 8-24] events, P = .017), and the occurrence of severe asynchrony (AI > 10%) was also less under NAVA (P = .027). Ineffective efforts and delayed cycling were significantly less with NAVA (P < .05 for both). NAVA was also associated with reduced Td (0 [IQR, 0-30] milliseconds vs 90 [IQR, 30-130] milliseconds, P < .001) and inspiratory time in excess (10 [IQR, 0-28] milliseconds vs 125 [IQR, 20-312] milliseconds, P < .001), but T(In) was similar under PSV and NAVA. The EAdi signal to its maximal value was higher during NAVA than during PSV ( P = .017). There were no significant differences in arterial blood gases or patient discomfort under PSV and NAVA.Conclusion: In view of specific experimental conditions, our comparison of PSV and NAVA indicated that NAVA significantly reduced severe patient-ventilator asynchrony and resulted in similar improvements in gas exchange during NIV for ARF.Trial Registry: ClinicalTrials.gov; No.: NCT01426178; URL: www.clinicaltrials.gov. [ABSTRACT FROM AUTHOR]

Humoral factors play an important role in the control of exercise hyperpnea. The role of neuromechanical ventilatory factors, however, is still being investigated. We tested the hypothesis that the afferents of the thoracopulmonary system, and consequently of the neuromechanical ventilatory loop, have an influence on the kinetics of oxygen consumption (Vo2), carbon dioxide output (Vco2), and ventilation (VE) during moderate intensity exercise. We did this by comparing the ventilatory time constants (τ) of exercise with and without an inspiratory load. Fourteen healthy, trained men (age 22.6 ± 3.2 yr) performed a continuous incremental cycle exercise test to determine maximal oxygen uptake (Vo2 max = 55.2 ± 5.8 ml·min-1·kg-1). On another day, after unloaded warm-up they performed randomized constant-load tests at 40% of their Vo2 max for 8 min, one with and the other without an inspiratory threshold load of 15 cmH2O. Ventilatory variables were obtained breath by breath. Phase 2 ventilatory kinetics (Vo2, Vco2, and VE) could be described in all cases by a monoexponential function. The bootstrap method revealed small coefficients of variation for the model parameters, indicating an accurate determination for all parameters. Paired Student's t-tests showed that the addition of the inspiratory resistance significantly increased the τ during phase 2 of Vo2 (43.1 ± 8.6 vs. 60.9 ± 14.1 s; P « 0.001), Vco2 (60.3 ± 17.6 vs. 84.5 ± 18.1 s; P « 0.001)and VE(59.4 ± 16.1 vs. 85.9 ± 17.1 s; P « 0.001). The average rise in τ was 41.3% for Vo2, 40.1% for Vco2, and 44.6% for VE. The τ changes indicated that neuromechanical ventilatory factors play a role in the ventilatory response to moderate exercise. [ABSTRACT FROM AUTHOR]

Tremendous progress in paediatrics has significantly improved the overall prognosis of chronic diseases and transferred the mortality from childhood to adulthood in an era where sedentary lifestyle, obesity and associated cardiovascular risk factors are rapidly increasing. The promotion of regular exercise is of utmost priority in the management of these patients. The cardiopulmonary exercise test (CPET) gives important prognostic information on functional capacity, haemodynamic response and can facilitate a safe decision-making process when prescribing exercise programs and sport participation for these children. Despite a growing interest in CPET and individualized rehabilitation programs for chronic diseases, we still face the lack of reference values for paediatric CPET and even more for "extreme" patients (especially in terms of weight). The main aim of this study is to define references values VO2 max and establish Z-scores in the paediatric population including extreme weights. This cross-sectional study was carried out between November 2010 and November 2020 in two tertiary care paediatric cardiology reference centres and included children referred for a non-severe functional symptom linked to exercise (murmur, palpitation or dyspnoea) or for a medical sports certificate. These children had a completely normal check-up, including physical examination, ECG, echocardiography and spirometry. 909 children were included, 213 were overweight/obese and 107 were underweight. For both sexes, the best model was logarithmic with the combination of height and BMI. The equations are cited in the Fig. 1. For the first time, we have paediatric reference values giving VO2 max Z-score that can be used for extreme weights. From this same cohort, we will soon publish the Z-score of the other CPET parameters and thus facilitate the interpretation of this paediatric examination and facilitate its use. [ABSTRACT FROM AUTHOR]

Objective We aimed to compare the cardiopulmonary fitness of children with congenital heart diseases (CHD) to that of age- and gender-adjusted controls. We also intended to identify clinical characteristics associated with maximum oxygen uptake (VO2 max ) in this population. Methods We included in a cross-sectional multicentre study a total of 798 children (496 CHD and 302 controls) who underwent a complete cardiopulmonary exercise test (CPET). The association of clinical characteristics with VO2 max was studied using a multivariate analysis. The study was approved by the South Mediterranean IV Ethics Committee (2009-A00423-54) and registered on ClinicalTrials.gov ( NCT01202916 ). Informed consent was obtained from all parents. Results Mean VO2 max in the CHD group and control represented 93 ± 20% and 107 ± 17% of predicted values, respectively. VO2 max was significantly lower in the CHD group, overall (37.8 ± 0.3 vs. 42.6 ± 0.4 mL/kg/min, P < 0.0001) and for each group ( P < 0.05) ( Table 1 ). The mean VO2 max decline per year was significantly higher in CHD than in the controls overall (−0.84 ± 0.10 vs −0.19 ± 0.14 mL/kg/min/year, P < 0.01), for males (−0.72 ± 0.14 vs. 0.11 ± 0.19 mL/kg/min/year, P < 0.01), and for females (−1.00 ± 0.13 vs. −0.55 ± 0.21 mL/kg/min/year, P = 0.05) ( Fig. 1 ). VO2 max was associated with body mass index, ventilatory anaerobic threshold, female gender, restrictive ventilatory disorder, right ventricle systolic hypertension, tricuspid regurgitation, the number of cardiac catheter or surgery procedures, and the presence of a genetic anomaly. Conclusions This comparative CPET study provided, for the first time, relevant values of VO2 max and their clinical determinants in the largest reported cohort of CHD children compared to a control group. Although the magnitude of the difference was not large, VO2 max among children with CHD was significantly lower than in normal children. We suggest performing CPET in routine follow-up of these patients. [ABSTRACT FROM AUTHOR]

Cardio-pulmonary exercise test (CPET) provides accurate evaluation of physical capacity and disease severity in children with congenital heart disease (CHD). However, in clinical practice, full participation to obtain optimal measure of VO2 max may be difficult. As an alternative, the oxygen uptake efficiency slope (OUES) is a reproducible and reliable parameter measured during CPET, which does not require a maximal exercise to be interpretable. This study aimed to evaluate the OUES of a large cohort of children with CHD, and to compare the results with those of healthy controls. We also intended to identify, in this specific population, the clinical and CPET variables associated with the OUES. This cross-sectional multicenter study enrolled 709 children (407 CHD and 302 healthy controls). The association of clinical characteristics with weight-normalized OUES (OUES kg) was studied using a multivariable analysis. The mean OUES kg was significantly lower in CHD than in healthy controls (respectively 38.6 ± 8.5 and 43.9 ± 8.5; P < 0.001). The OUES kg was predominantly affected in the most severe CHD. The OUES kg correlated well with VO2 max (r = 0.85, P < 0.001). The decrease of OUES kg was associated with increased age, increased BMI, number of cardiac catheter or surgical procedures, female gender and decreased FVC (Z-score). The OUES is significantly impaired in children with CHD and strongly correlates with VO2 max. The OUES has the same clinical determinants as VO2max and therefore may be of interest in submaximal exercise. [ABSTRACT FROM AUTHOR]

Impaired pulmonary function is an independent predictor of mortality in adult congenital heart disease (CHD), but has been scarcely studied in the paediatric CHD population. To compare the pulmonary function of children with CHD to healthy controls, and evaluate its association with clinical outcomes, exercise capacity, and quality of life. Cross-sectional multicentre study among 834 children (555 CHD and 279 control subjects) who underwent a complete spirometry and a cardiopulmonary exercise test (CPET). The 5th centile (Z-score = −1.64) was used to define the lower limit of normal. The association of clinical and CPET variables with spirometry was studied using a multivariate analysis. Children and their parents filled in the Kidscreen health-related quality of life questionnaire. Forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) Z-scores values were lower in children with CHD than controls (−0.4 ± 1.5 vs. 0.4 ± 1.3, P < 0.001 and −0.5 ± 1.4 vs. 0.4 ± 1.2, P < 0.001, respectively), without any obstructive airway disorder. Restrictive pattern was more frequent in CHD patients than in controls (20% vs. 4%, P < 0.0001). FVC Z-scores were predominantly impaired in complex CHD, such as heterotaxy (−1.1 ± 0.6), single ventricle (−1.0 ± 0.2), and complex anomalies of the ventricular outflow tracts (−0.9 ± 0.1). In multivariate analysis, FVC was affected by the age, the body mass index, the maximum oxygen uptake, the genetic anomalies, the number of cardiac surgery and cardiac catheter procedures. FVC and FEV1 correlated with self and proxy-related quality of life scores. These results suggest that pulmonary function should be monitored early in life, from childhood, in the CHD population. [ABSTRACT FROM AUTHOR]

Les arythmies ventriculaires gauches représentent une des principales causes de décès chez les patients atteint de la Dystrophie Musculaire de Duchenne (DMD). Dans le muscle squelettique, nous avons mis évidence une augmentation de la s-nytrosylation du canal calcique de type 1 du réticulum sarcoplasmique (RS), le récepteur à la ryanodine (RyR1), à l’origine d’une augmentation de la fuite spontanée du Ca2+ du RS (Bellinger et al (2009), Nature Med,). L’objectif de ce travail, a été de déterminer si une s-nytrolsylation accrue de l’isoforme cardiaque du RyR (RyR2) pouvait rendre compte des arythmies ventriculaires chez des souris déficientes en dystrophine, les souris mdx. En western blot, l’augmentation de la s-nytrosylation du RyR2 dans les cœurs de souris mdx apparaît dés l’ages de 40 jours. Cette s-nytrosylation est associée à la dissociation de la sous-unité régulatrice du RyR2, la calstabin 2 (ou FKBP12.6), et est à l’origine d’une augmentation de la fuite spontanée du Ca2+ du RS, mesurée par microscopie confocale (Fluo-4) sur des cardiomyocytes ventriculaires isolés. 10 jours de traitement par voie orale avec le S107 (Rycal) qui stabilise la liaison de la calstabin 2 avec le RyR2, empêche la fuite du Ca2+ du RS, normalise la signalisation Ca2+, et prévient le déclenchement d’arythmies induit par une stimulation adrénergique que ce soit au niveau cellulaire (Isoprenaline : 100nM) ou in vivo (Isoprenaline : 2mg/kg). En conclusion, dés les premiers stades de la pathologie, la s-nytrosylation du RyR2 induit la dissociation de la calstabin 2 du RyR2 et augmente la fuite diastolique de Ca2+ ce qui dans des conditions de stress augmente la prévalence des arythmies. Une normalisation précoce de la fonction du RyR2 apparaît comme une cible thérapeutique nouvelle dans la prévention des phénomènes arythmogénes au cours de la DMD. [Copyright &y& Elsevier]

Objectives – The aim of the present study was to investigate the influence of a short distance triathlon (1.5 km swim, 40 km cycle, and 10 km run) on respiratory muscle performance.Methods and results – Nine male triathletes underwent the measurement of respiratory muscle strength (maximal expiratory and inspiratory pressures), and respiratory muscle endurance (Time limit), before the competition (Pre-T), at the end (Post-T) and 24 h later (post-T-24 h). The results showed, 1) the absence of significant difference in maximal expiratory pressure (P > 0.05), 2) a significant decrease in maximal inspiratory pressure and time limit at Post-T and Post-T-24 h (P < 0.05).Conclusion – We concluded that a short distance triathlon induced an inspiratory muscle fatigue, showed by a significant decrease in strength and endurance of these muscles. [Copyright &y& Elsevier]

Objectifs Les scores de QDV sont corrélés à la VO2max chez l’adulte insuffisant cardiaque. Une telle corrélation n’a pas été établie en cardiopédiatrie. Matériels et méthodes Deux cent deux enfants belges et français porteurs d’une cardiopathie congénitale (CC) âgés de 8 à 18 ans ont effectué une VO2 (tapis roulant n = 96, cycle ergomètre n = 106). La sévérité de la CC a été stratifiée en 4 groupes. Tous les enfants et les parents ont rempli le Kidscreen, questionnaire générique de QdV. Les parents ont signé un consentement éclairé (ClinicalTrials.gov # NCT01202916 ). Résultats VO2max, seuil ventilatoire, pente VE/VCO2 et pouls d’oxygène étaient corrélés à la sévérité de la CC. Le bien-être physique était corrélé à VO2max (enfants : r = 0,27, p < 0,0001 et parents : r = 0,43, p < 0,0001) et seuil ventilatoire (parents : r = 0,22, p < 0,01 et enfants : r = 0,31, p < 0,0001). Dans le groupe « tapis roulant », la corrélation était forte entre VO2max et bien-être physique (parents : r = 0,57, p < 0,0001 et enfants : r = 0,40, p < 0,0001). Conclusions VO2max et seuil ventilatoire sont corrélés à la qualité de vie des enfants porteurs de CC dans la dimension physique. Dans un essai clinique cardiopédiatrique, nous suggérons d’utiliser les scores physiques estimés par les parents comme critère de jugement. [ABSTRACT FROM AUTHOR]