Hemodynamic, not ventilatory, inefficiency is associated with high VE/VCO2 slope in repaired, noncyanotic congenital heart disease

Ventilatory efficiency in post-COVID-19 athletes

Limitation in exercise capacity has not been described in athletes affected by SARS-CoV-2 infection. However, patients who have recovered from COVID-19 without cardiopulmonary impairment show exaggerated ventilatory response during exercise. Therefore, we aimed to evaluate the ventilatory efficiency (VEf) in competitive athletes recovered from COVID-19 and to characterize the ventilation versus carbon dioxide relationship (VE/VCO2 ) slope in this population. Thirty-seven competitive athletes with COVID-19 were recruited for this study. All participants underwent spirometry, echocardiography, and cardiopulmonary exercise testing (CPET). z-FVC values and end-title pressure of CO2 (PET CO2 ) were lower in the third tertile compared with the first tertile: -0.753 ± 0.473 vs. 0.037 ± 0.911, p = 0.05; 42.2 ± 2.7 vs. 37.1 ± 2.5 mmHg, p < 0.01. VE/VCO2 slope was significantly correlated to maximal VCO2 /VE and maximal VO2 /VE: coefficient = -0.5 R2  = 0.58, p < 0.0001 and coefficient = -0.3 R2  = 0.16, p = 0.008. Competitive athletes affected by SARS-CoV-2 infection, without cardio-respiratory disease sequel, may present ventilatory inefficiency (ViE), without exercise capacity limitation. FVC is higher in athletes with better ventilatory performance during exercise, and increased VE/VCO2 slope is inversely correlated to max VCO2 /VE and max VO2 /VE.

Correlation between three-dimensional echocardiography and cardiopulmonary fitness in patients with univentricular heart: A cross-sectional multicentre prospective study

BACKGROUND

The prognosis of patients with a functional single ventricle has improved, with better cardiopulmonary fitness, health-related quality of life and survival. Conventional echocardiography remains the first-line technique in single ventricle follow-up. Three-dimensional (3D) echocardiography has shown recent value in congenital cardiology, but its ability to predict functional status in patients with a single ventricle remains unknown.

AIM

To evaluate, in patients with a single ventricle, the association between 3D echocardiography variables and functional status determined by cardiopulmonary fitness.

METHODS

Children and adults with a functional single ventricle were prospectively enrolled in this multicentre study. Cardiopulmonary fitness was assessed by cardiopulmonary exercise test, with measures of maximum oxygen uptake (VO_2max) and ventilatory efficiency (VE/VCO₂ slope). 3D echocardiography was performed with off-line reproducibility analyses, using TomTec Arena™ software. Health-related quality of life was assessed using the SF-36 questionnaire.

RESULTS

A total of 33 patients were screened, and 3D echocardiography analyses were feasible in 22 subjects (mean age 28±9years). 3D echocardiography ejection fraction correlated with percent-predicted VO_2max (r=0.64, P<0.01), VE/VCO₂ slope (r=-0.41, P=0.05), two-dimensional echocardiography ejection fraction (r=0.55, P<0.01) and health-related quality of life physical functioning dimension (r=0.56, P=0.04). 3D echocardiography indexed end-systolic volume correlated with percent-predicted VO_2max (r=-0.45, P=0.03) and VE/VCO₂ slope (r=0.65, P<0.01). 3D echocardiography reproducibility was good.

CONCLUSIONS

Single ventricle ejection fraction and volumes measured by 3D echocardiography correlated with cardiopulmonary fitness, as determined by two main prognostic cardiopulmonary exercise test variables: VO_2max and VE/VCO₂ slope. Despite good reproducibility, 3D echocardiography feasibility remained limited. 3D echocardiography may be of value in single ventricle follow-up, provided that the technique and analysis software are improved.

The Effects of Exercise Training on Cardiopulmonary Exercise Testing and Cardiac Biomarkers in Adult Patients with Hypoplastic Left Heart Syndrome and Fontan Circulation

Background: Several studies have shown that adult patients with Hypoplastic Left Heart Syndrome (HLHS) and Fontan circulation have a reduced exercise tolerance that affects daily life. Recent studies have investigated the effects of aerobic exercise training in patients with univentricular heart; however, this research topic is still poorly studied. The aim of this study was to evaluate the effects of an aerobic exercise training program on cardiopulmonary exercise testing parameters and cardiac biomarkers in patients with HLHS. Methods: We enrolled 12 patients with a mean age of 24 ± 2.5 years (range 22−27 years), 50% male, with HLHS at Bambino Gesù Children’s Hospital IRCCS. All patients underwent a cardiopulmonary test and blood sampling before (T0) and after (T1) a 4-week aerobic exercise program. Cardiac biomarkers hs-cTnT, NT-proBNP, ST2, GDF-15 were studied. Results: Data analysis demonstrated an increase in cardiorespiratory performance after 4 weeks of aerobic exercise training activity. In particular, the data showed a significant improvement in test duration (p < 0.05), heart rate at rest (p < 0.05), heart rate recovery 1 min (p < 0.05), VO2 max (p < 0.01) and oxygen uptake efficiency slope (p < 0.05). At the same time, the data showed a significant reduction in NT-proBNP and ST2 values (p < 0.01 and p < 0.05, respectively) and a significant increase in GDF-15 (p < 0.01). No significant changes were found between the hs-cTnT values. Conclusions: Our study demonstrated the 4-week efficacy of an aerobic training program in improving cardiorespiratory performance and cardiac biomarker values in adult patients with HLHS and Fontan circulation. More studies with larger numbers of patients will be needed to confirm these data.

L-Arginine Improves Endurance to High-Intensity Interval Exercises in Overweight Men

The effects of acute consumption of L-Arginine (L-Arg) in healthy young individuals are not clearly defined, and no studies on the effects of L-Arg in individuals with abnormal body mass index undertaking strenuous exercise exist. Thus, we examined whether supplementation with L-Arg diminishes cardiopulmonary exercise testing responses, such as ventilation (VE), VE/VCO2, oxygen uptake (VO2), and heart rate, in response to an acute session of high-intensity interval exercise (HIIE) in overweight men. A double-blind, randomized crossover design was used to study 30 overweight men (age, 26.5 ± 2.2 years; body weight, 88.2 ± 5.3 kilogram; body mass index, 28.0 ± 1.4 kg/m2). Participants first completed a ramped-treadmill exercise protocol to determine VO2max velocity (vVO2max), after which they participated in two sessions of HIIE. Participants were randomly assigned to receive either 6 g of L-Arg or placebo supplements. The HIIE treadmill running protocol consisted of 12 trials, including exercise at 100% of vVO2max for 1 min interspersed with recovery intervals of 40% of vVO2max for 2 min. Measurements of VO2 (ml·kg-1·min-1), VE (L/min), heart rate (beat per min), and VE/VCO2 were obtained. Supplementation with L-Arg significantly decreased all cardiorespiratory responses during HIIE (placebo+HIIE vs. L-Arg+HIIE for each measurement: VE [80.9 ± 4.3 L/min vs. 74.6 ± 3.5 L/min, p < .05, ES = 1.61], VE/VCO2 [26.4 ± 1.3 vs. 24.4 ± 1.0, p < .05, ES = 1.8], VO2 [26.4 ± 0.8 ml·kg-1·min-1 vs. 24.4 ± 0.9 ml·kg-1·min-1, p < .05, ES = 2.2], and heart rate [159.7 ± 6.3 beats/min vs. 155.0 ± 3.7 beats/min, p < .05, d = 0.89]). The authors conclude consuming L-Arg before HIIE can alleviate the excessive physiological strain resulting from HIIE and help to increase exercise tolerance in participants with a higher body mass index who may need to exercise on a regular basis for extended periods to improve their health.

The V̇e/V̇co2 slope: a useful tool to evaluate the physiological status of children with congenital heart disease

Cardiopulmonary exercise test (CPET) is becoming a key examination to assess physical capacity and disease severity in pediatric cardiology. The V̇e/V̇co₂ 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 congenital heart disease (CHD). Nevertheless, the use of the V̇e/V̇co₂ slope in children remains limited in the absence of reference values and clearly identified clinical determinants. This study aimed to compare the V̇e/V̇co₂ slope in a pediatric cohort with CHD to that of age- and gender-adjusted healthy controls. We also intended to identify the clinical and CPET variables associated with V̇e/V̇co₂ slope in this population. This cross-sectional study was carried out between November 2010 and September 2015 in two tertiary care pediatric cardiology reference centers. A total of 700 children were enrolled (399 CHD and 301 healthy controls). The mean V̇e/V̇co₂ slope was significantly higher in the CHD subjects than in healthy subjects (31.6 ± 4.8 vs. 29.3 ± 4.8; P < 0.001). The V̇e/V̇co₂ slope was higher in children with significant pulmonary regurgitation, tricuspid regurgitation, right ventricular hypertension, and right ventricle outflow tract (RVOT) obstacle. In the CHD group, V̇e/V̇co₂ slope increase was associated with body mass index, the presence of a RVOT obstacle, the number of cardiac catheter procedures, as well as low age, forced vital capacity, tidal volume, and [Formula: see text]. Increased V̇e/V̇co₂ 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 V̇e/V̇co₂ slope.NEW & NOTEWORTHY Using V̇e/V̇co₂ slope is useful for children with congenital heart disease. V̇e/V̇co₂ slope is sensitive to pulmonary blood flow maldistribution during exercise, this concerns congenital heart disease with pulmonary regurgitation, tricuspid regurgitation, right ventricular hypertension, and right ventricle outflow tract obstacle. V̇e/V̇co₂ slope is a good parameter to follow single ventricles and right heart residual lesions (tetralogy of Fallot; pulmonary atresia; truncus arteriosus…).

Does Restrictive Lung Function Affect the Exercise Capacity in Patients with Repaired Tetralogy of Fallot?

Patients with repaired Tetralogy of Fallot (rTOF) have decreased exercise capacity (XC) and restrictive lung function (RLF). Our objective was to determine the association between RLF and impaired XC in patients with rTOF. This was a single center retrospective review of patients with rTOF who underwent a cardiopulmonary treadmill exercise testing and spirometry from 2005 to 2015. Patients with a respiratory exchange ratio ≥ 1.05 and peak heart rate > 90% of predicted value were included. Forced vital capacity (FVC) and Forced expiratory volume in 1st second of forceful expiration (FEV₁) were used to classify the lung function. Exercise parameters such as peak oxygen uptake (VO₂), % of predicted VO₂ (%VO₂), Metabolic equivalents (METS), and exercise time (ET) were compared between the two groups (i) compared patients with normal lung function (normal FEV₁, FVC, and FEV₁/FVC > 80%) (ii) RLF (FVC < 80%, normal or increased FEV₁/FVC > 80%). In our cohort (n = 151, 52% male, mean age ± SD of 22.3 ± 9.1 years), patients with RLF (n = 73) compared to those with normal lung function (n = 86) had a lower peak VO₂ (30.8 ± 8.6 vs. 36.6 ± 9.8 mL/kg/min; p < 0.001) and shorter exercise time (9:23 ± 1:78 vs. 10:23 ± 1:62 min, p < 0.001). On multivariate regression analysis, RLF was independently associated with reduced XC (VO₂%) (β-coefficient - 0.182, p < 0.02) after controlling for age and gender. RLF is common in patients with rTOF and is associated with decreased XC. The contribution of RLF to reduced XC in this population should be considered prior to therapeutic decisions.

A prospective 5-year study of exercise performance following Melody valve implant

BACKGROUND

The long-term benefits of Melody valve implant for right ventricular outflow tract conduit obstruction or insufficiency on exercise capacity are undefined.

METHODS

As part of the Melody valve clinical trial, 136 patients with congenital heart disease underwent serial cardiopulmonary exercise testing prior to, 6 months after, and annually for up to 5 years postimplant.

RESULTS

Mean age at Melody valve implantation was 22.4 ± 0.9 years (range 7-53 years). The 95 patients who completed the study protocol provide the basis of this report. An initial improvement in % predicted workload was present at 6 months postimplant; however, at the final (5 year) follow-up, sustained or further improvements in workload were not demonstrated for the entire cohort compared to baseline. By subgroup analysis, age <17 years at implant and pulmonary regurgitation as the primary lesion were variables associated with sustained improvement in exercise performance. There were sustained improvements in the ventilatory equivalents for O₂ (minute ventilation/O₂ intake, P = .01) and CO₂ (minute ventilation/CO₂ output, P < .01) at the ventilatory anaerobic threshold at the study conclusion. Improvements in forced vital capacity were also observed during the study but not sustained at the final follow-up.

CONCLUSIONS

A cautious appraisal of the cardiovascular benefits of Melody valve implant on sustained improvements in exercise performance appears warranted. Although the observed changes in pulmonary function suggest improved restrictive lung physiology and more efficient gas exchange, after an initial increase in % predicted performance, neither sustained nor further improvements in exercise performance were observed, except in specific patient subgroups.

The Role of Cardiopulmonary Exercise Testing for Decision Making in Patients with Repaired Tetralogy of Fallot

Tetralogy of Fallot is the most common form of cyanotic congenital heart disease. As a result of the surgical strategies employed at the time of initial repair, chronic pulmonary regurgitation (PR) is prevalent in this population. Despite sustained research efforts, patient selection and timing of pulmonary valve replacement (PVR) to address PR in young asymptomatic patients with repaired tetralogy of Fallot (rToF) remain a fundamental but as yet unanswered question in the field of congenital heart disease. The ability of the heart to compensate for the chronic volume overload imposed by PR is critical in the evaluation of the risks and benefits of PVR. The difficulty in clarifying the functional impact of PR on the cardiovascular capacity may be in part responsible for the uncertainty surrounding the timing of PVR. Cardiopulmonary exercise testing (CPET) may be used to assess abnormal cardiovascular response to increased physiologic demands. However, its use as a tool for risk stratification in asymptomatic adolescents and young adults with rToF is still ill-defined. In this paper, we review the role of CPET as a potentially valuable adjunct to current risk stratification strategies with a focus on asymptomatic rToF adolescents and young adults being considered for PVR. The role of maximal and submaximal exercise measurements to identify young patients with a decreased or borderline low peak VO₂ resulting from impaired ventricular function is explored. Current knowledge gaps and research perspectives are highlighted.

[Cardiac rehabilitation for children and adults with congenital heart disease]

Advances in heart surgery over the past 30 years have significantly improved the prognosis of congenital heart diseases (CHD). Therefore, the epidemiology of CHD has changed dramatically with a shift of mortality from pediatrics to adulthood and an increased prevalence of complex CHD. Today, caregivers and patients focus their interests to new perspectives: improving the quality of life, practicing sports, improving psychosocial care. Cardiac rehabilitation is completely integrated in these new therapeutic strategies. The starting point is the cardiopulmonary exercise test (CPET), with the measurement of oxygen uptake, or "VO2". CPET is now recommended in the follow-up of the adults with CHD. Maximum oxygen uptake correlates to the quality of life of children and adults with CHD. The principles of the rehabilitation in patients with heart failure may usually be applied to CHD patients. Some studies in complex CHD showed improvement of VO2 and quality of life after rehabilitation, without any adverse events. However few physicians have the experience in rehabilitation among CHD patients, especially children. Randomized trials on cardiac rehabilitation in adult and pediatric CHD patients are essential to increase the level of evidence and lead to specific guidelines in this population.