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Background: Patients with moderate aortic stenosis (AS) may experience symptoms and adverse outcomes. The aim of this study was to determine whether patients with moderate AS exhibited objective evidence of exercise limitation, compared with age and sex matched controls and if so, to determine which echocardiographic parameters predicted exercise ability. Methods: This was a prospective case control study of patients with moderate AS (peak velocity (Vmax) 3.0–3.9 m/s, mean gradient (MG) 20-39mmHg, aortic valve area (AVA)1.1-1.5cm2) and left ventricular ejection fraction (LVEF) ≥ 55%. All patients underwent cardiopulmonary stress echocardiography. Results: 25 patients with moderate AS (Vmax 3.5 ± 0.2mmHg, mean gradient 28 ± 5mmHg, AVA 1.2 ± 0.1cm2, LVEF 61 ± 4%) were compared with 25 controls. % predicted oxygen uptake efficiency slope (OUES), % predicted O2 pulse and VO2 at anaerobic threshold (AT) were significantly lower in patients compared with controls (OUES 79 ± 15 vs. 89 ± 15%, p = 0.013). VO2 did not significantly differ between cases and controls. Conclusion: Objective measures of exercise capacity including OUES, O2 pulse and VO2 at AT are significantly lower in patients with moderate AS compared with controls, suggesting that these parameters may be more useful than VO2 where patients may be unable to complete a maximal exercise test. Risk stratification using cardiopulmonary exercise echocardiography may help to identify patients with moderate AS who are at increased risk of cardiovascular events and should be considered for more intensive surveillance and intervention. Trial registration: Clinical trial number MRC 0225 IRAS 207395. [ABSTRACT FROM AUTHOR]

Background: Wild-type transthyretin cardiac amyloidosis (ATTRwt) is an infiltrative disease leading to restrictive cardiomyopathy. We aimed to characterise exercise capacity in ATTRwt and to identify predictors of cardiopulmonary fitness, focusing on echocardiographic and clinical parameters. Methods: We studied 110 ATTRwt patients from a prospective single-centre registry (2020-2024) by cardiopulmonary exercise testing (CPET). Besides CPET, all patients underwent comprehensive clinical assessment including follow-up for mortality. In 32 patients follow-up CPET after 1 year was available. Results: In ATTRwt, reduced aerobic capacity (pVO2 16 [13–18] ml/kg/min), and ventilatory inefficiency (VE/VCO2 slope 35 [30–43]) were common. In the multivariable regression analysis, we identified TAPSE/sPAP ratio as predictive for pVO2 (p = 0.019) and ventilatory efficiency (p = 0.004), while left ventricular ejection fraction or measures of left ventricular hypertrophy were not predictive. Concordantly, TAPSE/sPAP ratio assessed at baseline predicted pVO2 at 1-year follow-up (p = 0.009). Furthermore, patients with a TAPSE/sPAP ratio below the median of 0.38 mm/mmHg presented a higher risk of all-cause death (p = 0.009). Conclusion: In ATTRwt the TAPSE/sPAP ratio, a marker of right ventricular coupling, was an independent predictor of aerobic capacity assessed by CPET, at baseline and after 1 year, highlighting the importance of right ventricular assessment for risk stratification. [ABSTRACT FROM AUTHOR]

Background: Cardiopulmonary Exercise Testing (CPET) provides detailed insights into athletes' cardiovascular and pulmonary function, making it a valuable tool in assessing recovery and injury risks. However, traditional statistical models often fail to leverage the full potential of CPET data in predicting reinjury. Machine learning (ML) algorithms offer promising capabilities in uncovering complex patterns within this data, allowing for more accurate injury risk assessment. Objective: This study aimed to develop machine learning models to predict reinjury risk among elite soccer players using CPET data. Specifically, we sought to identify key physiological and performance variables that correlate with reinjury and to evaluate the performance of various ML algorithms in generating accurate predictions. Methods: A dataset of 256 elite soccer players from 16 national and top-tier teams in Iran was analyzed, incorporating physiological variables and categorical data. Several machine learning models, including CatBoost, SVM, Random Forest, and XGBoost, were employed to predict reinjury risk. Model performance was assessed using metrics such as accuracy, precision, recall, F1-score, AUC, and SHAP values to ensure robust evaluation and interpretability. Results: CatBoost and SVM exhibited the best performance, with CatBoost achieving the highest accuracy (0.9138) and F1-score (0.9148), and SVM achieving the highest AUC (0.9725). A significant association was found between a history of concussion and reinjury risk (χ² = 13.0360, p = 0.0015), highlighting the importance of neurological recovery in preventing future injuries. Heart rate metrics, particularly HRmax and HR2, were also significantly lower in players who experienced reinjury, indicating reduced cardiovascular capacity in this group. Conclusion: Machine learning models, particularly CatBoost and SVM, provide promising tools for predicting reinjury risk using CPET data. These models offer clinicians more precise, data-driven insights into athlete recovery and risk management. Future research should explore the integration of external factors such as training load and psychological readiness to further refine these predictions and enhance injury prevention protocols. [ABSTRACT FROM AUTHOR]

Objectives: This study aims to evaluate the therapeutic effect of Vericiguat through cardiopulmonary exercise testing (CPET) in patients with chronic heart failure and reduced ejection fraction (HFrEF). Methods: A prospective observational study was conducted from May 2022 to May 2023, focusing on patients with HFrEF admitted to our hospital. Eligible patients were sequentially numbered and enrolled based on specific inclusion and exclusion criteria. They were divided into two groups: one receiving standard heart failure therapy and the other receiving standard therapy plus Vericiguat. Data were collected at baseline and at 1, 3, and 6 months post-discharge, including NT-proBNP, sST2, and echocardiographic assessments. All patients underwent CPET before discharge and again six months post-discharge for within-subject comparisons. Results: The study enrolled 158 patients, with 79 in each treatment arm. No significant baseline differences were observed in the Weber Functional Classification or CPET parameters. At six months, the Vericiguat group exhibited a significant reduction in patients classified as C (from 31.6 to 7.5%) and D (from 31.6 to 3.7%), with P values less than 0.05. Additionally, Vericiguat significantly improved Peak Oxygen Consumption (from 14.24 ± 6.21 to 19.03 ± 4.87 ml/kg/min) and Anaerobic Threshold (from 10.48 ± 3.82 to 13.48 ± 3.31 ml/kg/min). Compared to the standard treatment group, the Vericiguat group demonstrated significantly higher Peak Oxygen Consumption, Anaerobic Threshold, and a lower Carbon Dioxide Equivalent Slope, with P values all below 0.05. Conclusions: Vericiguat safely enhances exercise tolerance, as evaluated by CPET, in high-risk patients with HFrEF. [ABSTRACT FROM AUTHOR]

Background: In patients with chronic coronary syndromes (CCS), increased ventilation/carbon dioxide production ( V ̇ E/ V ̇ CO2) slope has been found to predict disease progression and mortality, similarly to patients with heart failure (HF); however, increased chemosensitivity, a well-established predictor for mortality in patients with HF, has rarely been assessed in patients with CCS. Method: Patients with CCS, HF with reduced ejection fraction (EF < 50%), healthy controls (45+ years), and young healthy adults (<35 years) were recruited. For patients, a V ̇ E/ V ̇ CO2 slope ≥36 was an inclusion criterion. The Duffin rebreathing method was used to determine the resting end-expiratory partial pressure of carbon dioxide (PETCO2), ventilatory recruitment threshold (VRT), and slope (sensitivity) during a hyperoxic (150 mmHg O2) and hypoxic (50 mmHg O2) rebreathing test to determine the central and peripheral chemosensitivity. Results: In patients with CCS, HF, controls, and young healthy adults, median V ̇ E/ V ̇ CO2 slopes were 40.2, 41.3, 30.5, and 28.0, respectively. Both patient groups had similarly reduced hyperoxic VRT (at PETCO2 42.1 and 43.2 mmHg) compared to 46.0 and 48.8 mmHg in the control and young healthy adults. Neither hypoxic VRT nor hyper- or hypoxic slopes were significantly different in patients compared to controls. Both patient groups had lower resting PETCO2 than controls, but only patients with HF had increased breathing frequency and rapid shallow breathing at rest. Conclusion: In patients with HF and/or CCS and excess ventilation, central chemoreflex VRT was reduced independently of the presence of HF. Low VRTs were related to resting excess ventilation in patients with CCS or HF; however, rapid shallow breathing at peak exercise was present only in patients with HF. Clinical trial registration number: NCT05057884. [ABSTRACT FROM AUTHOR]

(1) Background: To assess the impact of excessive body fat on cardiorespiratory fitness (CRF) and coronary artery health in children and adolescents following acute Kawasaki disease (KD-CA). (2) Methods: A retrospective study of KD-CA patients (ages 8–16) who completed cardiopulmonary exercise testing (CPET) in the last five years. Participants were classified based on body mass index (BMI) and fat mass index (FMI) into normal and excessive adiposity groups. Coronary artery (CA) Z-scores were calculated using the Lambda-Mu-Sigma method, with peak VO2 Z-scores (peak VO2 Z-score) derived from a database of Hong Kong Chinese children and adolescents. Primary outcomes included peak VO2 Z-score, Max-Z (maximum CA Z-score), anaerobic threshold metabolic equivalent (AT MET), peak MET, and pulse oxygen. Statistical analyses were conducted to evaluate differences across groups. (3) Results: A total of 112 KD-CA patients were included (mean age: 11.71 ± 2.54 years). The mean peak VO2 Z-score was −0.63 ± 0.98. Participants with normal BMI and FMI had significantly higher pulse oxygen levels compared to those with excessive BMI and FMI (both p < 0.001). Additionally, those with normal FMI showed higher AT MET, peak MET, peak VO2 Z-score (p = 0.049), and lower Max-Z (p = 0.026) than excessive FMI participants. Boys, especially those with normal adiposity, had superior AT MET, peak MET, pulse oxygen, and Max-Z compared to girls. (4) Conclusions: Excessive adiposity in KD-CA patients is associated with reduced CRF and elevated Max CA Z-score. These findings highlight the need to monitor body composition to optimize cardiovascular health in this population. [ABSTRACT FROM AUTHOR]

Background: Transcatheter tricuspid valve intervention (TTVI) has shown promising results with persistent reduction of tricuspid regurgitation (TR) and improvements in functional class and quality of life (QOL). Objectives: To analyze the impact of TTVI on maximal and submaximal exercise capacity (SEC). Methods: Constant work-rate exercise-time (CWRET) testing reflects SEC, which is more likely to be relevant for daily life activities and provides more differentiated physiological insight into the nature of exercise intolerance. Thus, 30 patients undergoing TTVI (21 direct annuloplasty and 9 edge-to-edge repair) received cardiopulmonary exercise testing (CPET) and CWRET (at 75% of maximum work rate in the initial CPET) before and 3 months after TTVI. Results: Patients' age was 80.5 [74.8–82.3] years and 53.3% were female. TR reduction ≥ 2 grades was achieved in 93.3% (TR grade ≤ moderate in 83.3%). Echocardiography revealed improved right ventricular (RV) characteristics with decreased RV basal diameter (47.0 mm [43.0–54.3] vs. 41.5 mm [36.8–48.0]; p < 0.001) and decreased inferior caval vein diameter. CWRET testing showed a significantly improved SEC (246.5 s [153.8–416.8] vs. 338.5 s [238.8–611.8] p = 0.001). Maximum oxygen uptake showed a positive trend without statistically significant differences (9.9 ml/min/kg [8.6–12.4] vs. 11.7 ml/min/kg [9.7–13.3]; p = 0.31). In contrast to the six-minute-walking distance (6MWD), SEC correlated moderately with effective regurgitation orifice area reduction (r = 0.385; p = 0.036), increased cardiac output (r = 0.378; p = 0.039), and improved QOL (r = 387; p = 0.035). Conclusion: Improvements in exercise capacity after TTVI mainly occur in the submaximal rather than in the maximal exercise range and correlate with hemodynamic effects and QOL. This may have a methodological impact on assessment of exercise capacity in these patients. Improvements in exercise capacity mainly occur in the submaximal (Constant work-rate exercise-time, CWRET) rather than in the maximal exercise range (maximum oxygen consumption, peak VO2), and correlate with reduction in tricuspid regurgitation, hemodynamic effects and QOL [ABSTRACT FROM AUTHOR]

Summary Background Objectives Methods Results Conclusions Peak oxygen uptake (VO2) is considered the most important indicator of aerobic exercise capacity during cardiopulmonary exercise testing (CPET). However, its accuracy is compromised when maximal effort is not achieved. In such cases, submaximal parameters can serve as surrogates for assessing exercise performance.To compare the differences in maximal and submaximal exercise parameters between children with obesity and normal weight.A prospective study evaluating CPET using a treadmill completed by children with and without obesity.A total of 153 children (50.9% females) were divided into two groups: obese (n = 87) and non‐obese (n = 66). Children with obesity achieved lower exercise capacity (peakVO2 of 68% ± 16% vs. 89% ± 15%; p < 0.0001) with fewer achieving maximal effort (26.4% vs. 78.7%, respectively). VO2‐derived submaximal parameters showed a significantly lower oxygen uptake efficiency slope per body weight (OUES/kg) (30.5 ± 6.1 vs. 39.0 ± 9.5; p < 0.0001) and lower VO2 at ventilatory threshold (VO2@AT) (21.2 ± 4.6 vs. 26.4 ± 5.3, p = 0.0001) in the obese group, with no significant differences in the CO2‐derived parameters.Maximal exercise data in children with obesity is frequently unavailable due to failure to achieve maximal effort. Submaximal parameters, such as OUES and VO2@AT, may be useful substitute options for assessing the health and functional level of this population. [ABSTRACT FROM AUTHOR]

Background and Aims: Individuals with steatotic liver disease (SLD) are at high cardiovascular disease (CVD) risk, but approaches to characterise and mitigate this risk are limited. By investigating relations, and shared metabolic pathways, of hepatic steatosis/fibrosis and cardiorespiratory fitness (CRF), we sought to identify new avenues for CVD risk reduction in SLD. Methods: In Framingham Heart Study (FHS) participants (N = 2722, age 54 ± 9 years, 53% women), vibration‐controlled transient elastography (VCTE) was performed between 2016–2019 to assess hepatic steatosis (continuous attenuation parameter [CAP]) and fibrosis (liver fibrosis measure [LSM]). Concurrently, participants underwent maximum effort cardiopulmonary exercise testing (CPET), and metabolomic profiling (201 circulating metabolites) was performed in a subsample (N = 1268). Results: Mean BMI was 28.0 ± 5.3, 27% had hepatic steatosis, 7.6% had fibrosis, and peak oxygen uptake (VO2) was 26.2 ± 6.8 mL/kg/min in men and 20.7 ± 6.0 mL/kg/min in women (95% predicted overall). In linear models adjusted for cardiometabolic risk factors, greater CAP and LSM were associated with lower peak VO2 (p ≤ 0.002 for all), and the CAP association remained significant after BMI adjustment (p < 0.0001). We observed shared metabolic architecture of CAP, LSM, and peak VO2, with metabolites mediating up to 35% (for CAP) and 74% (for LSM) of the association with peak VO2. Metabolite mediators included amino acids and derivatives implicated in cardiometabolic risk and both protective and deleterious lipid species. Conclusions: Hepatic steatosis and fibrosis are associated with CRF impairment in the community, and these relations are partly mediated by pathways of altered lipid metabolism and general cardiometabolic risk. [ABSTRACT FROM AUTHOR]

Introduction: Survivors of severe COVID-19 face complex challenges and a high degree of pulmonary sequelae. Therefore, we aim to describe their ongoing health burden. Methods: In this single-center prospective cohort study, COVID-19 ICU survivors were invited 3 and 6 months after ICU discharge. We examined pulmonary function with pulmonary function tests (PFT) and cardiopulmonary exercise testing (CPET), and we established health-related quality of life (HRQL) and health status (HS) with the EuroQol five-dimension five-level (EQ-5D-5L), the short-form health survey 12 (SF-12), and the modified British Medical Research Council dyspnea scale (mMRC) questionnaires. Results: Out of the 53 individuals screened, 23 participated in this study. Throughout both assessment points, participants maintained PFT results within range, apart from a decline in the transfer factor of the lung for carbon monoxide (TLCO). CPET showed improved fitness but persistent ventilatory deficiencies, indicated by altered dead space ventilation (VD/VT) and elevated arterial-alveoli gradient for oxygen (AaDO2). HRQL and HS remained compromised, with both physical (PCS) and mental component summary (MCS) scores significantly lower than the standardized norm population scores. Also, there was a rise in the prevalence of issues related to mobility, pain/discomfort, and anxiety/depression, and an increase in reported dyspnea. Conclusion: These results enhance our comprehension of the complex difficulties faced by COVID-19 ICU survivors. Six months post-discharge, CPET revealed the presence of ventilatory insufficiencies. Additionally, there was a decline in HRQL and HS, notably affected by mental health concerns and an increase in the level of dyspnea. [ABSTRACT FROM AUTHOR]

Cardiac manifestations in systemic sclerosis (SSc) are variable and are associated with a poor prognosis, frequently resulting in impaired right ventricular function and heart failure. A high proportion of patients with SSc experience pulmonary arterial hypertension (PAH), interstitial lung disease, or myocardial involvement, all of which can lead to exercise intolerance. In this context, cardiopulmonary exercise testing (CPET) is a useful tool for diagnosing exercise intolerance, elucidating its pathophysiology, and assessing its prognosis. CPET can also identify patients with SSc at higher risk of developing PAH. Despite its utility, current guidelines for CPET do not include the evaluation of patients with SSc, nor do standard SSc management guidelines consider CPET in the clinical work-up. This review summarizes the development, supporting evidence, and application of CPET in assessing cardiac involvement in patients with SSc. [ABSTRACT FROM AUTHOR]

Background Left bundle branch block (LBBB) is a rare conduction disorder in athletes associated with ventricular dyssynchrony, which can lead to left ventricular systolic dysfunction and exercise intolerance. Inappropriate sinus tachycardia (IST) is characterized by an excessive heart rate (HR) that is not related to physiological needs, often resulting in reduced exercise capacity. Managing these conditions in athletes can be challenging, as standard treatments like beta-blockers and ivabradine, while effective in controlling HR, are described to be associated with a reduction in maximal exercise performance. Case summary A 50-year-old amateur athlete presented with exercise intolerance, LBBB, and mild dilated cardiomyopathy due to ventricular dyssynchrony. Resting electrocardiogram and 24-h monitoring confirmed IST. Initial cardiopulmonary exercise testing (CPET) off-therapy showed rapid HR increase during exertion, an early plateau in oxygen pulse, and reduced peak oxygen consumption (VO2, 22.1 mL/kg/min, 76% of the predicted value). After 1 month of ivabradine 5 mg b.i.d. there was some improvement in these parameters. At the third follow-up, with combined therapy of ivabradine (5 mg b.i.d.) and metoprolol (50 mg b.i.d.), the HR response during exercise normalized, and CPET parameters significantly improved, with peak VO2 reaching 29.2 mL/kg/min (101% of the predicted value). Discussion This case highlights a paradoxical improvement in exercise tolerance and peak VO2 with combined ivabradine and beta-blocker therapy in a patient with IST. The treatment optimized the HR response during exercise, suggesting that individualized strategies can enhance exercise performance in patients with IST and mild cardiomyopathy, despite the expected limitations of these medications. [ABSTRACT FROM AUTHOR]

To investigate the potential contribution of chest wall muscle area (CWMA) to the ventilatory efficiency and exercise capacity in patients with Systemic Sclerosis (SSc) without interstitial lung disease (ILD). Forty-four consecutive SSc patients [F = 37, median age 53.5 years (IQR 43.5–58)] were examined using chest high-resolution computed tomography (HRCT), pulmonary function tests and cardiopulmonary exercise testing (CPET). The CWMA was evaluated at the level of the ninth thoracic vertebra on CT images by two independent evaluators blinded to the patient information. CPET parameters analyzed were maximum oxygen uptake (VO2 max) and VO2 at anaerobic threshold (VO2@AT); minute ventilation (VE); maximum tidal volume (VT). A statistically significant positive correlation was found between CWMA and maximum workload (r = 0.470, p < 0.01), VO2 max ml/min (r = 0.380, p < 0.01), VO2@AT (r = 0.343, p < 0.05), VE (r = 0.308, p < 0.05), VT (r = 0.410, p < 0.01) and VO2/heart rate (r = 0.399, p < 0.01). In multiple regression analysis, VO2 max (ml/min) was significantly associated with CWMA [β coefficient = 5.226 (95% CI 2.824, 7.628); p < 0.001], diffusing capacity for carbon monoxide (DLco) [β coefficient = 6.749 (95% CI 1.460, 12.039); p < 0.05] and body mass index (BMI) [β coefficient = 41.481 (95% CI 8.802, 74.161); p < 0.05]. In multiple regression analysis, maximum workload was significantly associated with CWMA [β coefficient = 0.490 (95% CI 0.289, 0.691); p < 0.001], DLco [β coefficient = 0.645 (95% CI 0.202, 1.088); p < 0.01] and BMI [β coefficient = 3.747 (95% CI 1.013, 6.842); p < 0.01]. In SSc-patients without ILD, CWMA represents an important variable in exercise capacity and can be evaluated by the mediastinal window available in the HRCT images required for lung disease staging. [ABSTRACT FROM AUTHOR]

Background/Objectives: Heart failure (HF) constitutes a complex clinical syndrome that is highly prevalent worldwide, comprises a serious prognosis, and results in a reduced quality of life. Exercise capacity is one of the most significant parameters involved in the prognosis in HF patients. Our objective was to evaluate the relationship between the selected cardiopulmonary exercise testing (CPET) parameters and the concentration of novel biomarker sST2 in a group of patients with heart failure with reduced ejection fraction (HFrEF). Methods: A group of 135 patients with HFrEF was enrolled in this prospective cohort study. Patients were in the stable phase of the disease in the prior 4 weeks and received optimal medical treatment. Clinical and biochemical parameters were investigated. All patients performed maximal CPET. Results: The mean (SD) concentration of sST2 was 45.5 ± 39.2 ng/mL. Based on the CPET results, the cut-off value (52.377 ng/mL) was established, optimal for the discrimination of relative peakVO2 < 12 mL/kg/min. Patients were divided into two groups according to sST2 cut-off values determined with an ROC curve (AUC 0.692, 95% CI: 0.567–0.816). The mean relative peakVO2 in patients with higher sST2 was 14.5 ± 4.6 mL/kg/min, while in the second group, it was 17.6 ± 5.2 (p = 0.002). In the sST2 ≥ 52.377 ng/mL group, 55.6% of patients achieved VO2 < 50%. Subjects with lower sST2 values obtained higher values of PETCO2 (p < 0.001) and higher values of pulse O2 (p = 0.01). VE/VCO2slope (p = 0.002) was higher in patients with increased sST2 concentration. Conclusions: The concentration of sST2 protein is substantially associated with the clinical severity of heart failure with reduced left ventricular ejection fraction assessed by functional capacity through CPET. [ABSTRACT FROM AUTHOR]

Abstract High cardiac sympathetic drive and release of the sympathetic cotransmitter neuropeptide Y (NPY) are significant features of congestive heart failure (CHF), in which resting venous NPY levels are known to be associated with mortality. However, whether circulating NPY levels increase during exercise in CHF when they are already elevated is controversial. We sought to establish the dynamics of circulating NPY levels in CHF patients treated with contemporary medical therapy and devices in relationship to indices of performance linked to long‐term prognosis. CHF patients (n = 15) underwent cardiopulmonary exercise testing with venous blood sampling at rest, peak exercise and recovery. These patients had significantly higher resting venous NPY levels compared with an age‐ and sex‐matched control group of patients (n = 16) with normal left ventricular function (40 ± 6.9 vs. 9.0 ± 4.6 pg/mL, respectively; P

Yuting Liu,1 Yanting Liang,1 Huan Ma,2 Hengyuan Gao,3,4 Xinzhou Zhang1,5 1Department of Nephrology, Shenzhen People’s Hospital, The Second Clinical Medical College, Jinan University, The First Affiliated Hospital, Southern University of Science and Technology, Shenzhen, Guangdong, 518020, People’s Republic of China; 2Department of Cardiology, Guangdong Cardiovascular Institute, Guangdong Provincial People’s Hospital, Guangdong Academy of Medical Sciences, Southern Medical University, Guangzhou, Guangdong, 510080, People’s Republic of China; 3Department of Thyroid Surgery, the First Affiliated Hospital of Jinan University, Guangzhou, Guangdong, 510630, People’s Republic of China; 4Department of Thyroid and Breast Surgery,Shenzhen People’s Hospital, The Second Clinical Medical College, Jinan University, The First Affiliated Hospital, Southern University of Science and Technology, Shenzhen, Guangdong, 518020, People’s Republic of China; 5Shenzhen Key Laboratory of Kidney Diseases, The Second Clinical Medical College, Jinan University; The First Affiliated Hospital, Southern University of Science and Technology, Shenzhen, Guangdong, 518020, People’s Republic of ChinaCorrespondence: Hengyuan Gao, Email geland136@163.com Xinzhou Zhang, Email xinzhouzhang1946@163.comObjective: The American Heart Association has recently emphasized the significance of the cardiovascular-kidney-metabolic (CKM) syndrome. However, the cumulative impact of these factors on cardiorespiratory fitness remains inadequately characterized. This study aimed to examine the responses observed during cardiopulmonary exercise testing (CPET) of CKM syndrome patients and explore the potential correlation between cardiorespiratory fitness and hemoglobin concentration in this cohort.Design: Cross-sectional study.Methods: We retrospectively collected medical data of 8206 patients who underwent CPET from 2012– 2022. Among the 878 individuals enrolled, 12 were healthy controls, 809 had isolated CVD, and 57 were in CKM stage 4. After propensity score matching, 112 patients were included in the matched cohort analysis, with 56 each in the CVD and CKM groups. CPET responses were compared between the groups using propensity matched analysis. Additionally, simple mediation models were employed to investigate the potential mediating role of hemoglobin concentration in the association between CKM syndrome and peak VO2.Results: After propensity score-matching, CKM stage 4 was associated with diminished cardiorespiratory fitness compared to the other two groups. This included diminished exercise capacity, reflected by shorter exercise time, lower maximum workload (and its percent predicted value), and reduced peak VO2 (including its percent predicted value and peak VO2/kg). Additionally, cardiac autonomic function was impaired, as evidenced by decreased heart rate recovery (HRR) and a reduced slope of HR recovery (all p< 0.05). Mediation model regression analysis indicated a significant and direct detrimental effect of CKM syndrome on peak VO2 (β = − 228.502; P = 0.003), and a significant indirect partial effect of hemoglobin concentration on the direct effect (β = − 335.718; P < 0.001), with the percentage mediated through hemoglobin concentration of 46.9%.Conclusion: Individuals with CKM syndrome demonstrate compromised responses to CPET manifested by diminished exercise capacity and cardiac autonomic function. While diminished peak oxygen uptake can be partly explained by hemoglobin concentration as we found, further research is necessary to understand other underlying mechanisms.Keywords: cardiovascular-kidney-metabolic, cardiovascular disease, diabetes, chronic kidney disease, cardiorespiratory fitness, Cardiopulmonary Exercise Testing

Abstract Objectives This study aims to evaluate the therapeutic effect of Vericiguat through cardiopulmonary exercise testing (CPET) in patients with chronic heart failure and reduced ejection fraction (HFrEF). Methods A prospective observational study was conducted from May 2022 to May 2023, focusing on patients with HFrEF admitted to our hospital. Eligible patients were sequentially numbered and enrolled based on specific inclusion and exclusion criteria. They were divided into two groups: one receiving standard heart failure therapy and the other receiving standard therapy plus Vericiguat. Data were collected at baseline and at 1, 3, and 6 months post-discharge, including NT-proBNP, sST2, and echocardiographic assessments. All patients underwent CPET before discharge and again six months post-discharge for within-subject comparisons. Results The study enrolled 158 patients, with 79 in each treatment arm. No significant baseline differences were observed in the Weber Functional Classification or CPET parameters. At six months, the Vericiguat group exhibited a significant reduction in patients classified as C (from 31.6 to 7.5%) and D (from 31.6 to 3.7%), with P values less than 0.05. Additionally, Vericiguat significantly improved Peak Oxygen Consumption (from 14.24 ± 6.21 to 19.03 ± 4.87 ml/kg/min) and Anaerobic Threshold (from 10.48 ± 3.82 to 13.48 ± 3.31 ml/kg/min). Compared to the standard treatment group, the Vericiguat group demonstrated significantly higher Peak Oxygen Consumption, Anaerobic Threshold, and a lower Carbon Dioxide Equivalent Slope, with P values all below 0.05. Conclusions Vericiguat safely enhances exercise tolerance, as evaluated by CPET, in high-risk patients with HFrEF.

Abstract Background Psychological disorders, such as anxiety and depression, are considered to be one of the causes of noncardiac chest pain (NCCP). And these patients can be challenging to differentiate from coronary artery disease (CAD), leading to a considerable number of patients still undergoing angiography. We aim to develop a practical prediction model and nomogram using cardiopulmonary exercise testing (CPET), to help identify these patients. Methods 1,531 eligible patients’ electronic medical record data were obtained from Guangdong Provincial People’s Hospital. They were randomly divided into a training dataset (N = 918) and a testing dataset (N = 613) at a ratio of 6:4, and 595 cases without missing data were also selected from testing dataset to form a complete dataset. The training set is used to build the model, and the testing set and the complete set are used for internal validation. Eight machine learning (ML) methods are used to build the model and the best model is finally adopted. Results The model built by logistic regression performed the best, and among the 29 parameters, six parameters were determined to be valuable parameters for establishing the diagnostic equation and nomogram. The nomogram showed favorable calibration and discrimination with an area under the receiver operating characteristic curve (AUC) of 0.857 in the training set, 0.851 in the testing set, and 0.848 in the complete set. Meanwhile, decision curve analysis demonstrated the clinical utility of the nomogram. Conclusions A nomogram using CPET to distinguish anxiety/depression from CAD was developed. It may optimize the disease management and improve patient prognosis.

Wen Zhang,1 Jinguo Xu2 1The Second Affiliated Hospital of Anhui Medical University, Cardiovascular Department for Gerontism, HeFei, People’s Republic of China; 2The First Affiliated Hospital of Anhui Medical University, Department of Cardiovascular Surgery, HeFei, People’s Republic of ChinaCorrespondence: Jinguo Xu, The First Affiliated Hospital of Anhui Medical University, Department of Cardiovascular Surgery, HeFei, People’s Republic of China, Email xujinguo@ahmu.edu.cnObjective: To analyze the relationship between the cardiopulmonary function and prognosis of patients with coronary heart disease after percutaneous coronary intervention (PCI).Methods: A total of 153 patients with coronary heart disease who underwent PCI from January 2018 to April 2020 were enrolled in this study. Through careful assessment, cardiopulmonary exercise test (CPX) was performed 5 to 7 days after PCI. Patients were followed up every 3 months by outpatient examination or telephone visiting for 3 years after discharge. Clinical outcomes were followed up, including cardiac death, rehospitalization, heart failure, atrial fibrillation, stroke and transient ischemic attack. A single clinical event was defined as a poor prognosis and divided into a good prognosis group and a poor prognosis group according to the prognosis. By comparing the cardiorespiratory fitness (CRF) variables and clinical parameters, the variables that may affect the prognosis of patients were determined.Results: CRF decreased significantly in the poor prognosis group, and peak VO2, VO2/kg AT, PETCO2 and OUES decreased compared with the good prognosis group, and the differences were statistically significant. Heart rate reserve (HRR) increased in the poor prognosis group compared with the good prognosis group, and the difference was statistically significant. Among them, peak VO2 and acute myocardial infarction were independent risk factors for poor prognosis.Conclusion: Peak VO2 is an independent risk factor for the prognosis of cardiovascular disease after PCI for coronary heart disease.Keywords: coronary heart disease, cardiopulmonary exercise testing, percutaneous coronary intervention

Abstract Background Accurate preoperative risk assessment for major colorectal cancer (CRC) surgery remains challenging. Body composition (BC) and cardiopulmonary exercise testing (CPET) can be used to evaluate risk. The relationship between BC and CPET in patients undergoing curative CRC surgery is unclear. Methods Consecutive patients undergoing CPET prior to CRC surgery between 2010 and 2020 were identified between two different UK hospitals. Body composition phenotypes such as sarcopenia, myosteatosis, and visceral obesity were defined using widely accepted thresholds using preoperative single axial slice CT image at L3 vertebrae. Relationships between clinicopathological, BC, and CPET variables were investigated using linear regression analysis. Results Two hundred eighteen patients with stage I–III CRC were included. The prevalence of sarcopenia, myosteatosis, and visceral obesity was 62%, 33%, and 64%, respectively. The median oxygen uptake at anaerobic threshold (VO2 at AT) was 12.2 mL/kg/min (IQR 10.6–14.2), and oxygen uptake at peak exercise (VO2 peak) was 18.8 mL/kg/min (IQR 15.4–23). On univariate linear regression analysis, male sex (P

Background The cardiopulmonary exercise testing (CPET) is a noninvasive process aiming to evaluate the respiratory and cardiovascular system during exercise. Aim To study the effect of obstructive sleep apnea (OSA) on cardiovascular system and exercise capacity and to correlate the severity of OSA with CPET parameters. Patients and methods Fifty patients (30 males and 20 females) were enrolled in this study, diagnosed as OSA based on polysomnography (apnea–hypopnea index ≥5). All patients were given a thorough medical history, a thorough physical examination, an arterial blood gas analysis before and after exercise, a pulmonary-function test, polysomnography, and a CPET. Results Patients with mild/moderate OSA had significantly higher oxygen consumption (VO2) at peak (ml/min) and predicted value. Predicted VO2/kg was significantly higher among patients with mild/moderate OSA. Also, patients with mild/moderate OSA had significantly higher LT. Out of enrolled patients, three (6%), 15 (30%), and 32 (64%) patients had mild, moderate, and severe exercise impairment, respectively. Majority (90%) of the patients with severe OSA had severe exercise impairment, while majority (70%) of those with mild/moderate OSA had moderate exercise impairment. Conclusions OSA causes exercise impairment, which has a positive correlation with the severity of the disease.

Background: Psychological disorders, such as anxiety and depression, are considered to be one of the causes of noncardiac chest pain (NCCP). And these patients can be challenging to differentiate from coronary artery disease (CAD), leading to a considerable number of patients still undergoing angiography. We aim to develop a practical prediction model and nomogram using cardiopulmonary exercise testing (CPET), to help identify these patients. Methods: 1,531 eligible patients' electronic medical record data were obtained from Guangdong Provincial People's Hospital. They were randomly divided into a training dataset (N = 918) and a testing dataset (N = 613) at a ratio of 6:4, and 595 cases without missing data were also selected from testing dataset to form a complete dataset. The training set is used to build the model, and the testing set and the complete set are used for internal validation. Eight machine learning (ML) methods are used to build the model and the best model is finally adopted. Results: The model built by logistic regression performed the best, and among the 29 parameters, six parameters were determined to be valuable parameters for establishing the diagnostic equation and nomogram. The nomogram showed favorable calibration and discrimination with an area under the receiver operating characteristic curve (AUC) of 0.857 in the training set, 0.851 in the testing set, and 0.848 in the complete set. Meanwhile, decision curve analysis demonstrated the clinical utility of the nomogram. Conclusions: A nomogram using CPET to distinguish anxiety/depression from CAD was developed. It may optimize the disease management and improve patient prognosis. [ABSTRACT FROM AUTHOR]

Purpose: Low cardiorespiratory fitness (CRF) increases the risk of postoperative morbidity and mortality following major surgery. Assessing CRF preoperatively, by measuring peak oxygen uptake (VO2peak) during cardiopulmonary exercise testing (CPET), is valuable yet not widely available. This study aimed to assess whether questionnaires could be used preoperatively to identify high-risk surgical patients. Methods: Healthy participants and patients who underwent CPET completed the FitMáx, Duke Activity Status Index (DASI), the modified 4-questions DASI (M-DASI-4Q), Veterans-Specific Activity Questionnaire (VSAQ), and Metabolic Equivalents of Task (MET) questionnaire. Questionnaire-VO2peak was compared with CPET-VO2peak. Overall performance of the questionnaires was assessed by the area under the curve (AUC) of receiver operating characteristic (ROC) curves. Furthermore, corresponding to the Youden index or pre-specified levels, sensitivity, specificity, and predictive values were determined. Results: In total, 361 participants were included. All questionnaires showed high AUC values to identify high-risk patients, defined on the basis of CPET-VO2peak thresholds. FitMáx and VSAQ demonstrated superior results compared to the other questionnaires. Based on the Youden index, the optimal questionnaire-VO2peak cut-off values were 20.6, 21.3, and 26.1 ml·kg−1·min−1 for the FitMáx and 16.3, 18.2, and 20.4 ml·kg−1·min−1 for the VSAQ corresponding to the VO2peak thresholds 16.0, 18.2 and 24.5 ml·kg−1·min−1 respectively. Conclusion: The ability to identify high-risk surgical patients preoperatively (defined by the CPET-VO2peak thresholds) by the FitMáx and the VSAQ indicates that they could be used to identify high-risk surgical patients. Patients with a poor predicted VO2peak ≤ 21.3 and ≤ 18.2 ml·kg−1·min−1, respectively for FitMáx and VSAQ, should be referred to formal preoperative (cardiopulmonary) exercise testing. Trial registration: The study was registered as NL-OMON23304 in the Overview of Medical Research in the Netherlands, retrospectively at 28–04-2020. [ABSTRACT FROM AUTHOR]

Objective: To identify the association between cardiopulmonary exercise testing (CPET) and outcomes of radical cystectomy (RC), as RC is historically associated with high rates of short‐ and long‐term morbidity and mortality. Methods: This quantitative systematic review and meta‐analysis was conducted in accordance with the Preferred Reporting Items for Systematic Review and Meta‐Analysis guidelines. An electronic literature search was conducted to identify all relevant studies evaluating the relationship between CPET parameters and RC outcomes. The primary outcome was short‐term mortality. Secondary outcomes included hospital length of stay (LOS) and rate of serious adverse events as defined by the Clavien–Dindo classification. Results: The search identified six studies for inclusion. A total of 546 patients underwent CPET prior to RC. There were significantly more deaths following RC observed in patients with poorer cardiopulmonary function (risk ratio RR 5.80, 95% confidence interval 4.96–6.78). There was no significant association between CPET parameters and adverse events or hospital LOS. Conclusions: The present systematic review and meta‐analysis identified a greater risk of 90‐day mortality in patients with poorer cardiorespiratory function, as measured by CPET. However, there remains a paucity of robust clinical data and further high‐quality studies are required to verify these results. [ABSTRACT FROM AUTHOR]

Aims: Cardiopulmonary exercise testing (CPET) combined with exercise echocardiography (CPETecho) allows simultaneous assessments of cardiac, pulmonary, and ventilation in heart failure (HF) with preserved ejection fraction (HFpEF). This study sought to determine whether simultaneous assessment of CPET variables could provide additive predictive value over exercise stress echocardiography in patients with dyspnoea. Methods and results: CPETecho was performed in 443 patients with suspected HFpEF (240 HFpEF and 203 controls without HF). Patients with HFpEF were divided based on peak oxygen consumption (VO2, ≥10 or <10 ml/min/kg) or the slope of minute ventilation to carbon dioxide production (VE vs. VCO2 slope ≥45.0 or <45.0). The primary endpoint was defined as a composite of all‐cause mortality, HF hospitalization, unplanned hospital visits requiring intravenous diuretics, or intensification of oral diuretics. During a median follow‐up of 399 days, the composite outcome occurred in 57 patients. E/e' ratio during peak exercise was associated with adverse outcomes. Patients with HFpEF and lower peak VO2 had increased risks of the composite event (hazard ratio [HR] 5.05, 95% confidence interval [CI] 2.65–9.62, p < 0.0001 vs. controls; HR 3.14, 95% CI 1.69–5.84, p = 0.0003 vs. HFpEF with higher peak VO2). Elevated VE versus VCO2 slope was also associated with adverse events in HFpEF. The addition of either the presence of abnormal peak VO2 or VE versus VCO2 slope increased the predictive ability over the model based on age, sex, atrial fibrillation, left atrial volume index, and exercise E/e' (p < 0.05). Conclusion: These data provide new insights into the role of CPETecho in patients with HFpEF. [ABSTRACT FROM AUTHOR]

Cardiac amyloidosis, encompassing both transthyretin (ATTR) and light-chain (AL) types, poses considerable challenges in patient management due to its intricate pathophysiology and progressive course. This narrative review elucidates the pivotal role of cardiopulmonary exercise testing (CPET) in the assessment of these patients. CPET is essential for evaluating disease progression by measuring cardio-respiratory performance and providing prognostic insights. This functional test is crucial not only for tracking the disease trajectory, but also for assessing the effectiveness of disease-modifying therapies. Moreover, CPET facilitates the customization of therapeutic strategies based on individual patient performance, enhancing personalized care. By objectively measuring parameters such as peak oxygen uptake (VO2 peak), ventilatory efficiency, and exercise capacity, clinicians can gain a deeper understanding of the degree of functional impairment and make informed decisions regarding treatment initiation, adjustment, and anticipated outcomes. This review emphasizes the importance of CPET in advancing personalized medicine approaches, ultimately striving to improve the quality of life and clinical outcomes for patients with cardiac amyloidosis. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate correlations between cardiac magnetic resonance imaging (cMRI) at rest including strain imaging and variables derived from quantitative cardiopulmonary exercise testing using a treadmill in patients with pectus excavatum. Methods: We retrospectively correlated the results of cMRI and cardiopulmonary exercise testing in 17 patients with pectus excavatum, in whom both examinations were performed during their pre-operative clinical evaluation. In addition to cardiac volumetry, we assessed the strain rates of both ventricles using a feature-tracking algorithm of a piece of commercially available post-processing software. Results: Right ventricular (RV) ejection fraction correlated negatively with heart rate at anaerobic threshold (rho = −0.543, p = 0.024). A positive correlation between radial strain rate at the RV base and percentage of predicted maximum heart rate (rho = 0.72, p = 0.001) was shown, with equivalent results for circumferential strain rate (rho = −0.64, p = 0.005). Radial strain rate at the RV base correlated in a strongly negative way with maximum oxygen uptake (rho = −0.8, p < 0.001), with a correspondingly positive correlation for circumferential strain rate (rho = 0.73, p = 0.001). Conclusions: Quantitative parameters derived from cMRI at rest, especially those acquired at the most severely compressed RV base, correlated with cardiopulmonary exercise testing variables. The compression of the RV base by the sternum might be partially compensated by an increased strain rate to induce higher heart frequencies during exercise. However, high strain rates were associated with a higher disease severity and a lower maximum oxygen uptake, indicating a limitation of this compensation mechanism. [ABSTRACT FROM AUTHOR]

Cardiopulmonary exercise testing allows for a comprehensive assessment of the mechanism of exercise limitation in pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension. Competitive pathophysiologic mechanisms may affect the clinical interpretation of cardiopulmonary disease as they relate to dyspnea, leg fatigue, and exercise intolerance. [ABSTRACT FROM AUTHOR]

Aims Systemic sclerosis complicated by pulmonary arterial hypertension (SSc-PAH) is a rare condition with poor prognosis. The majority of patients are categorized as intermediate risk of mortality. Cardiovascular magnetic resonance (CMR) is well placed to reproducibly assess right heart size and function, but most patients with SSc-PAH have less overtly abnormal right ventricles than other forms of PAH. The aim of this study was to assess if exercise CMR measures of cardiac size and function could better predict outcome in patients with intermediate risk SSc-PAH compared with resting CMR. Methods and results Fifty patients with SSc-PAH categorized as intermediate risk underwent CMR-augmented cardiopulmonary exercise testing. Most patients had normal CMR-defined resting measures of right ventricular (RV) size and function. Nine (18%) patients died during a median follow-up period of 2.1 years (range 0.1–4.6). Peak exercise RV indexed end-systolic volume (ESVi) was the only CMR metric to predict prognosis on stepwise Cox regression analysis, with an optimal threshold < 39 mL/m2 to predict favourable outcome. Intermediate-low risk patients with peak RVESVi < 39 mL/m2 had significantly better survival than all other combinations of intermediate-low/-high risk status and peak RVESVi< or ≥39 mL/m2. In our cohort, ventilatory efficiency and resting oxygen consumption (VO2) were predictive of mortality, but not peak VO2, peak cardiac output, or peak tissue oxygen extraction. Conclusion Exercise CMR assessment of RV size and function may help identify SSc-PAH patients with poorer prognosis amongst intermediate risk cohorts, even when resting CMR appears reassuring, and could offer added value to clinical PH risk stratification. [ABSTRACT FROM AUTHOR]

(1) Background: Heart failure (HF) leads to functional disability and major cardiovascular events (MACEs). Cardiopulmonary exercise testing (CPET) is the gold standard for assessing aerobic capacity and prognostic stratification. This study aimed to evaluate the predischarge CPET variables in patients with acute decompensated HF and identify the submaximal CPET variables with prognostic value. (2) Methods: A retrospective cohort study was conducted at a tertiary center in Taiwan. Patients surviving their first episode of decompensated HF and undergoing predischarge CPET (February 2017 to January 2023) were analyzed. Follow-up was conducted until a MACE or administrative censoring (up to 5 years). Cox regression identified the significant predictors of MACE. (3) Results: The study included 553, 485, and 267 patients at the 3-month, 1-year, and 5-year follow-ups, respectively. MACE rates were 15.0%, 34.2%, and 50.9%. The VE/VCO2 slope was a significant predictor of MACE at all intervals. A VE/VCO2 slope >38.95 increased the risk of MACE by 2.49-fold at 3 months and 1.81-fold at 1 year (both p < 0.001). A slope > 37.35 increased the 5-year MACE risk by 1.75-fold (p = 0.002). (4) Conclusions: The VE/VCO2 slope is a significant submaximal CPET predictor of MACE in patients post-acute decompensated HF for both short- and long-term outcomes. [ABSTRACT FROM AUTHOR]

Purpose: Cardiopulmonary exercise testing (CPET) is considered the gold standard for assessing cardiorespiratory fitness. To ensure consistent performance of each test, it is necessary to adapt the power increase of the test protocol to the physical characteristics of each individual. This study aimed to use machine learning models to determine individualized ramp protocols based on non-exercise features. We hypothesized that machine learning models will predict peak oxygen uptake ( V ˙ O2peak) and peak power output (PPO) more accurately than conventional multiple linear regression (MLR). Methods: The cross-sectional study was conducted with 274 (♀168, ♂106) participants who performed CPET on a cycle ergometer. Machine learning models and multiple linear regression were used to predict V ˙ O2peak and PPO using non-exercise features. The accuracy of the models was compared using criteria such as root mean square error (RMSE). Shapley additive explanation (SHAP) was applied to determine the feature importance. Results: The most accurate machine learning model was the random forest (RMSE: 6.52 ml/kg/min [95% CI 5.21–8.17]) for V ˙ O2peak prediction and the gradient boosting regression (RMSE: 43watts [95% CI 35–52]) for PPO prediction. Compared to the MLR, the machine learning models reduced the RMSE by up to 28% and 22% for prediction of V ˙ O2peak and PPO, respectively. Furthermore, SHAP ranked body composition data such as skeletal muscle mass and extracellular water as the most impactful features. Conclusion: Machine learning models predict V ˙ O2peak and PPO more accurately than MLR and can be used to individualize CPET protocols. Features that provide information about the participant's body composition contribute most to the improvement of these predictions. Trial registration number: DRKS00031401 (6 March 2023, retrospectively registered). [ABSTRACT FROM AUTHOR]

We sought the cardiopulmonary exercise testing (CPET) parameter that most accurately reflected therapeutic efficacy in patients with hypertrophic cardiomyopathy (HCM). Well-being questionnaire, N-terminal brain natriuretic peptide measurements, echocardiography, and CPET were performed in patients with symptomatic non-obstructive HCM during phase II, randomized, open-label multicentre study, before and after 16 weeks of traditional or sacubitril/valsartan treatment. Patients were followed 36 months after the initial CPET. Primary endpoints were changes in: 1) peak oxygen consumption (VO 2); 2) VO 2 at anaerobic threshold (AT); 3) oxygen pulse; 4) minute ventilation (VE)/carbon-dioxide (CO 2) production slope; 5) VE/VCO 2 at AT (VE/VCO 2 _AT); 6) VE/VCO 2 nadir; 7) VE/VCO 2 intercept; and 8) partial end-tidal pressure of carbon-dioxide (P ET CO 2) change during CPET. Of 115 screened patients, 61 (52 ± 14 years, 43 % women) were included. Within subject therapy effects were detected only by the VE/VCO 2 intercept and P ET CO 2 change, whereas the differences between medical regimens were detected by differences in VE/VCO 2 nadir and VE/VCO 2 _AT changes after the treatment. The best predictors of the change in well-being were left ventricular outflow tract maximal gradient and VE/VCO 2 intercept (B = 0.41,0.36; SE = 0.16,0.30; CI = 0.14–0.79, 0.15–1.14; p = 0.006,0.016, respectively). Adverse cardiac events were best predicted by the initial VE/VCO 2 nadir. Ventilatory efficiency parameters outperform peak VO 2 in gauging therapy effects in patients with HCM. [ABSTRACT FROM AUTHOR]

Purpose: This study investigated the respiratory response and isocapnic buffering (IB) phase during an incremental exercise test to exhaustion in 16 child soccer players (11.9±0.9 years) and 18 youth soccer players (18.2±2.9 years). Methods: The IB phase was calculated as the difference in oxygen uptake (VO2) between the respiratory compensation point (RCP) and metabolic threshold (MT) and expressed in either absolute or relative values. Results: The maximal oxygen uptake (VO2max) was higher in youth players than in child players. For youth players, VO2max was measured at 55.9 ± 3.6 mL min−1 kg−1 and 74.9 ± 4.8 mL min−1 kg−0.75, while for child players, VO2max was 50.8 ± 4.1 mL min−1 kg−1 and 67.2 ± 6.1 mL min−1 kg−0.75 (p < 0.001). MT and RCP occurred at 69.8 ± 6.7% and 90.9 ± 6.9% of VO2max in child players and at 73.9 ± 5.1% and 91.5 ± 4.5% of VO2max in youth players, respectively. The two groups had no significant difference (p > 0.05). Absolute IB (10.6 ± 2.8 vs 9.7 ± 3.1 mL min−1 kg−1), relative IB (23.1 ± 5.7 vs 19.1 ± 6.1), and the ratio of RCP VO2 to MT VO2 (1.3 ± 0.09 vs 1.24 ± 0.09) were similar in child and youth players (p > 0.05). There was no difference in minute ventilation (V̇E, mL min−1 kg−1) and respiratory exchange ratio during exercise between the two groups (p > 0.05). During exercise, respiratory frequency, ventilatory equivalent for carbon dioxide (VE/VCO2) and oxygen (VE/VO2), VE/VCO2 slope, end-tidal O2 pressure were higher in child players than in youth players, while tidal volume (L kg−1), O2 pulse, and end-tidal CO2 pressure were lower (p < 0.05). Conclusion: Despite differences in aerobic capacity and ventilatory response to exercise, child players showed similar IB phase as youth players. Although child players have lower ventilation efficiency than youth players, the higher ventilation response for a given VCO2 may provide an advantage in regulating acid-base balance during intense exercise. [ABSTRACT FROM AUTHOR]

Quantitating exercise ventilatory and gas exchange dynamics affords insights into physiological control processes and cardiopulmonary dysfunction. We designed a novel waveform, the chirp waveform, to efficiently extract moderate-intensity exercise response dynamics. In the chirp waveform, work rate fluctuates sinusoidally with constant amplitude as sinusoidal period decreases progressively from ∼8.5 to 1.4 min over 30 min of cycle ergometry. We hypothesized that response dynamics of pulmonary ventilation (V̇ e) and gas exchange [oxygen uptake (V̇ o 2) and carbon dioxide output (V̇ co 2)] extracted from chirp waveform are similar to those obtained from stepwise transitions. Thirty-one participants [14 young healthy, 7 older healthy, and 10 patients with chronic obstructive pulmonary disease (COPD)] exercised on three occasions. Participants first performed ramp-incremental exercise for gas exchange threshold (GET) determination. In randomized order, the next two visits involved either chirp or stepwise waveforms. Work rate amplitude (20 W to ∼95% GET work rate) and exercise duration (30 min) were the same for both waveforms. A first-order linear transfer function with a single system gain (G) and time constant (τ) characterized response dynamics. Agreement between model parameters extracted from chirp and stepwise waveforms was established using Bland–Altman analysis and Rothery's concordance coefficient (RCC). V̇ e , V̇ o 2, and V̇ co 2Gs showed no systematic bias (P > 0.178) and moderate-to-good agreement (RCC > 0.772, P < 0.01) between waveforms. Similarly, no systematic bias (P = 0.815) and good agreement (RCC = 0.837, P < 0.001) was found for τV̇ o 2. Despite moderate agreement for τV̇ co 2 (RCC = 0.794, P < 0.001) and τV̇ e (RCC = 0.722, P = 0.083), chirp τ was less [−6.9(11.7) s and −12.2(22.5) s, respectively]. We conclude that the chirp waveform is a promising method for measuring exercise response dynamics and investigating physiological control mechanisms. NEW & NOTEWORTHY: We investigated the ability of a novel waveform to extract exercise ventilatory and gas exchange dynamics. In the chirp waveform, work rate fluctuates sinusoidally with constant amplitude as sinusoidal period decreases progressively over 30 min of exercise. In a study of 31 healthy individuals and patients with COPD, comparison of exercise dynamics derived from chirp to those from stepwise waveforms suggests that the chirp waveform is a promising method for derivation of exercise response dynamics. [ABSTRACT FROM AUTHOR]

Lung cancer represents the second most frequent neoplasm and the leading cause of neoplastic death among both women and men, causing almost 25% of all cancer deaths. Patients undergoing lung resection—both for primary and secondary tumors—require careful preoperative cardiopulmonary functional evaluation to confirm the safety of the planned resection, to assess the maximum tolerable volume of resection or to exclude surgery, thus shifting the therapeutic approach toward less invasive options. Cardiopulmonary reserve, pulmonary lung function and mechanical respiratory function represent the cornerstones of preoperative assessment of patients undergoing major lung resection. Spirometry with carbon monoxide diffusing capacity, split function tests, exercise tests and cardiologic evaluation are the gold standard instruments to safely assess the entire cardiorespiratory function before pulmonary resection. Although pulmonary mechanical and parenchymal function, together with cardiorespiratory compliance represent the mainstay of preoperative evaluation in thoracic surgery, the variables that are responsible for fitness in patients who have undergone lung resection have expanded and are being continually investigated. Nevertheless, because of the shift to older patients who undergo lung resection, a global approach is required, taking into consideration variables like frailty status and likelihood of postoperative functional deterioration. Finally, the decision to go ahead with surgery in fragile patients being consideredfor lung resection should be evaluated in a multispecialty preoperative discussion to provide a personalized risk stratification. The aim of this review is to focus on preoperative evaluation of cardiopulmonary reserve and surgical risk stratification of patients candidate for lung cancer resection. It does so by a literature search of clinical guidelines, expert consensus statements, meta-analyses, clinical recommendations, book chapters and randomized trials (1980–2022). [ABSTRACT FROM AUTHOR]

Cardiac rehabilitation (CR) is an important tool for improving fitness and quality of life in those with heart disease (HD). Few pediatric centers use CR to care for these patients, and virtual CR is rarely used. In addition, it is unclear how the COVID-19 era has changed CR outcomes. This study assessed fitness improvements in young HD patients participating in both facility-based and virtual CR during the COVID-19 pandemic. This retrospective single-center cohort study included new patients who completed CR from March 2020 through July 2022. CR outcomes included physical, performance, and psychosocial measures. Comparison between serial testing was performed with a paired t test with P < 0.05 was considered significant. Data are reported as mean ± standard deviation. There were 47 patients (19 ± 7.3 years old; 49% male) who completed CR. Improvements were seen in peak oxygen consumption (VO2, 62.3 ± 16.1 v 71 ± 18.2% of predicted, p = 0.0007), 6-min walk (6 MW) distance (401 ± 163.8 v 480.7 ± 119.2 m, p = < 0.0001), sit to stand (16.2 ± 4.9 v 22.1 ± 6.6 repetitions; p = < 0.0001), Patient Health Questionnaire-9 (PHQ-9) (5.9 ± 4.3 v 4.4 ± 4.2; p = 0.002), and Physical Component Score (39.9 ± 10.1 v 44.9 ± 8.8; p = 0.002). Facility-based CR enrollees were less likely to complete CR than virtual patients (60%, 33/55 v 80%, 12/15; p = 0.005). Increases in peak VO2 (60 ± 15.3 v 70.2 ± 17.8% of predicted; p = 0.002) were seen among those that completed facility-based CR; this was not observed in the virtual group. Both groups demonstrated improvement in 6 MW distance, sit-to-stand repetitions, and sit-and-reach distance. Completion of a CR program resulted in fitness improvements during the COVID-19 era regardless of location, although peak VO2 improved more for the in-person group. [ABSTRACT FROM AUTHOR]

Background: The cardiopulmonary exercise testing (CPET) is a noninvasive process aiming to evaluate the respiratory and cardiovascular system during exercise. Aim: To study the effect of obstructive sleep apnea (OSA) on cardiovascular system and exercise capacity and to correlate the severity of OSA with CPET parameters. Patients and methods: Fifty patients (30 males and 20 females) were enrolled in this study, diagnosed as OSA based on polysomnography (apnea–hypopnea index ≥5). All patients were given a thorough medical history, a thorough physical examination, an arterial blood gas analysis before and after exercise, a pulmonary-function test, polysomnography, and a CPET. Results: Patients with mild/moderate OSA had significantly higher oxygen consumption (VO2) at peak (ml/min) and predicted value. Predicted VO2/kg was significantly higher among patients with mild/moderate OSA. Also, patients with mild/moderate OSA had significantly higher LT. Out of enrolled patients, three (6%), 15 (30%), and 32 (64%) patients had mild, moderate, and severe exercise impairment, respectively. Majority (90%) of the patients with severe OSA had severe exercise impairment, while majority (70%) of those with mild/moderate OSA had moderate exercise impairment. Conclusions: OSA causes exercise impairment, which has a positive correlation with the severity of the disease. [ABSTRACT FROM AUTHOR]

Maximum oxygen uptake (V̇O2max) equations from developed countries are inaccurate for developing countries. Accordingly, we aimed to develop equations to predict treadmill V̇O2max over time based on variables other than exercise test in adults from the USA and Brazil undergoing cardiopulmonary exercise testing (CPET). We analyzed data from 2,170 adults who underwent two CPETs (1,307 men; 20-85 years) from the USA (n=1,880) and Brazil (n=290) with a second test after 2.0±1.7 years on average. We fit linear mixed-effects models to develop equations using 90% of the sample, randomly selected. In the remaining 10% of the cohort, we used the coefficient of variation, intraclass correlation coefficient, and the Bland and Altman plots to cross-validate the optimal equation. Our best linear mixed model equation was as follows: V̇O2max (mLO2·kg-1·min-1) = 62.01 - (0.23×Ageyears) - (0.001×Age×Age) - (0.65×Body mass indexkg/m 2) + (5.47×Sexfemales=0; males=1) + (2.78×CountryBrazil=0; USA=1) - (0.68×Arterial hypertensionno=0; yes=1) - (0.45×Hyperlipidemiano=0; yes=1) - (2.02×Smokingno=0; yes=1) - (4.36×Insufficiently activeno=0; yes=1) - (1.67×Beta-blockersno=0; yes=1); R2=0.566. Our main equation was reliable at baseline according to Bland and Altman plot results (mean difference, 0.01 mLO2·kg-1·min-1: 95%CI, -13.94 to 13.98; P=0.966) and over time (0.44 mLO2·kg-1·min-1: 95%CI, -13.5 to 12.4; P=0.439). Demographic and anthropometric attributes, cardiovascular risk, and beta-blockers are valuable for predicting V̇O2max at baseline and over time. The developed equations may apply to countries with socioeconomic and demographic characteristics such as Brazil and the USA.

BackgroundIn patients with chronic coronary syndromes (CCS), increased ventilation/carbon dioxide production (V̇E/V̇CO2) slope has been found to predict disease progression and mortality, similarly to patients with heart failure (HF); however, increased chemosensitivity, a well-established predictor for mortality in patients with HF, has rarely been assessed in patients with CCS.MethodPatients with CCS, HF with reduced ejection fraction (EF < 50%), healthy controls (45+ years), and young healthy adults (