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Standard cardiopulmonary exercise testing (CPET) produces a rich dataset but its current analysis is often limited to a few derived variables such as maximal or peak oxygen uptake (V̇O2). We tested whether breath-by-breath CPET data could be used to determine sample entropy (SampEn) in 81 healthy children and adolescents (age 7-18 years old, equal sex distribution). To overcome challenges of the relatively small time-series CPET data size and its nonstationarity, we developed a Python algorithm for short-duration physiological signals. Comparing pre- and post-ventilatory threshold (VT1) CPET phases, we found: (1) SampEn decreased by 9.46% for V̇O2 and 5.01% for V̇CO2 (p

Objectives: Fatigue is a prominent feature of long COVID (LC) and may be related to several pathophysiologic mechanisms, including immune hyperstimulation. Aerobic endurance exercise training may be a useful therapy, with appropriate attention to preventing post-exertional malaise. Methods: Fourteen participants completed a pilot study of aerobic exercise training (twenty 1.5 h sessions of over 10 weeks). Cardiorespiratory fitness, 6 min walk distance, quality of life, symptoms, 7-day physical activity, immunophenotype, and inflammatory biomarkers were measured before and after exercise training. Results: The participant characteristics at baseline were as follows: 53.5 ± 11.6 yrs, 53% f, BMI 32.5 ± 8.4, 42% ex-smokers, 15.1 ± 8.8 months since initial COVID-19 infection, low normal pulmonary function testing, V.O2peak 19.3 ± 5.1 mL/kg/min, 87 ± 17% predicted. After exercise training, participants significantly increased their peak work rate (+16 ± 20 W, p = 0.010) and V.O2peak (+1.55 ± 2.4 mL/kg/min, p = 0.030). Patients reported improvements in fatigue severity (-11%), depression (-42%), anxiety (-29%), and dyspnea level (-46%). There were no changes in 6MW distance or physical activity. The circulating number of CD3+, CD4+, CD19+, CD14++CD16, and CD16++CD14+ monocytes and CD56+ cells (assessed with flow cytometry) increased with acute exercise (rest to peak) and was not diminished or augmented by exercise training. Plasma concentrations of TNF-α, IL-6, IL-8, IL-10, INF-γ, and INF-λ were normal at study entry and not affected by training. Conclusions: Aerobic endurance exercise training in individuals with LC delivered beneficial effects on cardiorespiratory fitness, quality of life, anxiety, depression, and fatigue without detrimental effects on immunologic function.

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]

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]

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]

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]

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]

Patients with metabolic syndrome (MS) are at potential risk for cardiovascular disease and have received increasing public and medical attention. Studies have shown that regular physical exercise can effectively regulate metabolic indicators such as blood pressure, blood sugar and blood lipids, and play a positive role in reducing the risk of cardiovascular disease and improving the prognosis of patients. Exercise intensity has been identified as the most important aspect in reducing the risk of cardiovascular death and all-cause mortality in exercise intervention. Therefore, the design of exercise prescription which is both scientific and satisfying individual differences has become the focus of research. Most of the current clinical studies are based on the percentage of exercise intensity as the basis for the formulation of standardized exercise prescription for MS patients, while the studies on the individualized threshold of exercise intensity based on cardiopulmonary exercise test (CPET) are still few. CPET has shown that individualized exercise prescription can effectively reduce body composition index, blood pressure and blood glucose, improve cardiorespiratory function, exercise endurance and quality of life in MS patients. This paper reviewed the development of individualized exercise programs with different intensification according to threshold indexes in CPET, analyzed the intervention effects and possible mechanisms for MS patients and subgroups, and provided certain reference for the formulation and implementation of personalized exercise prescriptions for MS patients, and also provided references for in-depth research on individualized exercise intervention for MS. [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]

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]

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]

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]

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

Cardiopulmonary exercise testing (CPET) refers to a method of measuring various indicators of the human body under gradually increasing exercise loads to objectively evaluate cardiopulmonary reserve function and exercise endurance. Currently, CPET detection systems primarily measure subjects' ECG, respiratory flow, oxygen (O2), and carbon dioxide (CO2) parameters. This paper introduces a non-invasive multi-parameter exercise cardiopulmonary function evaluation system that incorporates impedance cardiography monitoring. The system integrates impedance cardiography monitoring with conventional CPET detection parameters and detects changes in the hemodynamic parameters of the body during exercise, aiding in the evaluation of exercise capacity. Additionally, the system features a portable design with Wi-Fi wireless transmission, which enhances its applicability.

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 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

Identification of the breathing cycle forms the basis of any breath-by-breath gas exchange analysis. Classically, the breathing cycle is defined as the time interval between the beginning of two consecutive inspiration phases. Based on this definition, several research groups have developed algorithms designed to estimate the volume and rate of gas transferred across the alveolar membrane ("alveolar gas exchange"); however, most algorithms require measurement of lung volume at the beginning of the ith breath (VLi-1; i.e., the end-expiratory lung volume of the preceding ith breath). The main limitation of these algorithms is that direct measurement of VLi-1 is challenging and often unavailable. Two solutions avoid the requirement to measure VLi-1 by redefining the breathing cycle. One method defines the breathing cycle as the time between two equal fractional concentrations of lung expired oxygen (Fo2) (or carbon dioxide; Fco2), typically in the alveolar phase, whereas the other uses the time between equal values of the Fo2/Fn2 (or Fco2/Fn2) ratios [i.e., the ratio of fractional concentrations of lung expired O2 (or CO2) and nitrogen (N2)]. Thus, these methods identify the breathing cycle by analyzing the gas fraction traces rather than the gas flow signal. In this review, we define the traditional approach and two alternative definitions of the human breathing cycle and present the rationale for redefining this term. We also explore the strengths and limitations of the available approaches and provide implications for future studies.

Background Postacute sequelae of COVID-19 (PASC) and HIV are both associated with reduced exercise capacity, but whether SARS-CoV-2 or PASC are associated with exercise capacity among people with HIV (PWH) is unknown. We hypothesized that PWH with PASC would have reduced exercise capacity from chronotropic incompetence. Methods and Results We conducted cross-sectional cardiopulmonary exercise testing within a COVID recovery cohort that included PWH with and without prior SARS-CoV-2 infection and people without HIV with prior SARS-CoV-2 infection (controls). We evaluated associations of HIV, SARS-CoV-2, and PASC with exercise capacity (peak oxygen consumption) and chronotropy (adjusted heart rate reserve). We included 83 participants (median age, 54 years; 35% women; 37 PWH): 23 out of 37 (62%) PWH and all 46 controls had prior SARS-CoV-2 infection, and 11 out of 23 (48%) PWH and 28 out of 46 (61%) without HIV had PASC. Peak oxygen consumption was reduced among PWH versus controls (80% predicted versus 99%, P=0.005), a difference of 5.5 mL/kg per minute (95% CI, 2.7-8.2; P

Most tests assess physiology at rest, whereas many symptoms occur with physical exertion, and physical activity is an integral part of healthy functioning and quality of life of a person. Today, cardiopulmonary exercise testing is considered the standard for identifying exercise limitations and differentiating their causes.Cardiopulmonary exercise testing is widely used in both basic and the latest research from cardiology and pulmonology to neurology and hematology and has great prognostic value. Cardiopulmonary exercise testing is considered the gold standard for non-invasive assessment of the cardiopulmonary system and physical performance. This study has become even more relevant and in demand due to the COVID-19 outbreak; now it plays an important role in the clinical assessment of recovering patients who have had COVID-19.Numerous indicators recorded at each stage of the study, taken together, allow us to obtain a complete picture of the work of the cardiovascular, respiratory and muscular systems, as well as to study the characteristics of the metabolic response to stress.This article contains a review of the literature on the history of the application and development of the cardiopulmonary exercise testing, its physiological characteristics and a study of the literature concerning application of studied method in medicine over the past 5 years. The search and analysis of articles were carried out using the scientometric databases PubMed, ScienceDirect, Google Academia.The presented article may be useful for young specialists working in functional diagnostics, cardiology and pulmonology, as well as for researchers and postgraduates whose work involves application of the cardiopulmonary exercise testing method.

Abstract Background After COVID-19 infection, 10–20% of patients suffer from varying symptoms lasting more than 12 weeks (Long COVID, LC). Exercise intolerance and fatigue are common in LC. The aim was to measure the maximal exercise capacity of the LC patients with these symptoms and to analyze whether this capacity was related to heart rate (HR) responses at rest and during exercise and recovery, to find out possible sympathetic overactivity, dysautonomia or chronotropic incompetence. Methods Cardiopulmonary exercise test was conducted on 101 LC patients, who were admitted to exercise testing. The majority of them (86%) had been treated at home during their acute COVID-19 infection. Peak oxygen uptake (VO2peak), maximal power during the last 4 min of exercise (Wlast4), HRs, and other exercise test variables were compared between those with or without subjective exercise intolerance, fatigue, or both. Results The measurements were performed in mean 12.7 months (SD 5.75) after COVID-19 infection in patients with exercise intolerance (group EI, 19 patients), fatigue (group F, 31 patients), their combination (group EI + F, 37 patients), or neither (group N, 14 patients). Exercise capacity was, in the mean, normal in all symptom groups and did not significantly differ among them. HRs were higher in group EI + F than in group N at maximum exercise (169/min vs. 158/min, p = 0.034) and 10 min after exercise (104/min vs. 87/min, p = 0.028). Independent of symptoms, 12 patients filled the criteria of dysautonomia associated with slightly decreased Wlast4 (73% vs. 91% of sex, age, height, and weight-based reference values p = 0.017) and 13 filled the criteria of chronotropic incompetence with the lowest Wlast4 (63% vs. 93%, p

Abstract Background Endurance athletes (EA) are an emerging population of focus for cardiovascular health. The oxygen uptake efficiency plateau (OUEP) is the levelling-off period of ratio between oxygen uptake (VO2) and ventilation (VE). In the cohort of EA, we externally validated prediction models for OUEP and derived with internal validation a new equation. Methods 140 EA underwent a medical assessment and maximal cycling cardiopulmonary exercise test. Participants were 55% male (N = 77, age = 21.4 ± 4.8 years, BMI = 22.6 ± 1.7 kg·m− 2, peak VO2 = 4.40 ± 0.64 L·min− 1) and 45% female (N = 63, age = 23.4 ± 4.3 years, BMI = 22.1 ± 1.6 kg·m− 2, peak VO2 = 3.21 ± 0.48 L·min− 1). OUEP was defined as the highest 90-second continuous value of the ratio between VO2 and VE. We used the multivariable stepwise linear regression to develop a new prediction equation for OUEP. Results OUEP was 44.2 ± 4.2 mL·L− 1 and 41.0 ± 4.8 mL·L− 1 for males and females, respectively. In external validation, OUEP was comparable to directly measured and did not differ significantly. The prediction error for males was − 0.42 mL·L− 1 (0.94%, p = 0.39), and for females was + 0.33 mL·L− 1 (0.81%, p = 0.59). The developed new prediction equation was: 61.37–0.12·height (in cm) + 5.08 (for males). The developed model outperformed the previous. However, the equation explained up to 12.9% of the variance (R = 0.377, R2 = 0.129, RMSE = 4.39 mL·L− 1). Conclusion OUEP is a stable and transferable cardiorespiratory index. OUEP is minimally affected by fitness level and demographic factors. The predicted OUEP provided promising but limited accuracy among EA. The derived new model is tailored for EA. OUEP could be used to stratify the cardiorespiratory response to exercise and guide training.

Background In the current rehabilitation environment, emotional issues and cognitive dysfunctions in stroke patients are often overshadowed by physical, speech, and swallowing difficulties, leading to their underestimation in clinical rehabilitation. This oversight can result in adverse outcomes, impacting the overall success of rehabilitation. Currently, clinical treatments primarily rely on pharmacotherapy to alleviate symptoms, which has limited effectiveness and can cause a range of adverse reactions. Objective To observe the efficacy of precision exercise prescriptions on anxiety, depression, and cognitive functions in stroke patients and to preliminarily analyze the underlying mechanisms of action. Methods A total of 84 stroke patients hospitalized in the Rehabilitation Department of Changzhou Dean Hospital from January 2022 to March 2023 were selected. They were randomly divided into a control group (42 patients) and an experimental group (42 patients). The control group received standard rehabilitation treatment, while the experimental group received precision exercise prescriptions based on cardiopulmonary exercise testing (CPET) results in addition to standard rehabilitation, over 12 weeks. The Self-rating Anxiety Scale (SAS), Self-rating Depression Scale (SDS), Mini-mental State Examination (MMSE) scores, and Homocysteine (Hcy) levels were compared before and after rehabilitation training in both groups. A Pearson correlation analysis was conducted between pre-rehabilitation Hcy levels and SAS, SDS, MMSE scores. Results All 42 patients in the experimental group completed the CPET and the 12-week precision exercise prescription rehabilitation without any adverse events. Before rehabilitation training, there were no statistically significant differences in SAS, SDS, MMSE scores, and Hcy levels between the two groups (P>0.05). After rehabilitation training, the scores of SAS, SDS, and Hcy levels in the experimental group were significantly lower compared to pre-treatment values (P0.05). Pearson correlation analysis revealed a positive correlation between Hcy levels and SAS, SDS scores (r-values of 0.420 and 0.507, respectively, P

Background: Supramaximal constant work rate tests (CWR) elicit intense hyperventilation, thus potentially up-shifting ventilation (⩒E)-to-carbon dioxide (CO2) responses when compared to graded exercise tests (GXT) in athletes. We predicted higher ventilatory efficiency on supramaximal CWR using a new method, challenging the classic orthodox interpretation of an increased ⩒E-⩒CO2 as ventilatory inefficiency. This misinterpretation could make difficult to differentiate between physiological hyperventilation from heart disease conditions in athletes. Methods: On different days, a GXT and a CWR at 110% of the maximal velocity achieved in the GXT were performed. Twenty-seven athletes completed the two tests and were compared for usual (linear regression) and log-transformed new variables for ventilatory efficiency through paired t-Student statistics. Results: The ⩒E-⩒CO2 slope (31.4 ± 4.9 vs. 26.2 ± 3.4, p < .001), ⩒E-⩒CO2 intercept (7.2 ± 7.5 vs. 2.8 ± 4.2, p < .007), ⩒E/⩒CO2 nadir (33.0 ± 3.6 vs. 25.4 ± 2.2, p < .001), ⩒CO2-log⩒E slope (10.8 ± 2.9 vs. 6.9 ± 2.2 L*logL−1, p < .001), and η⩒E (36.0 ± 12 vs. 22.8 ± 8.1%, p < .001) values were all significantly higher in the CWR compared to the GXT. We registered a bi-modal nadir response for ⩒E/⩒CO2 on CWR for 22 out of 27 subjects for the first time. A weak association was observed between ⩒E/⩒CO2 nadir (coefficient of determination ~ 27%) and time to exhaustion. Conclusions: The new method allows us to improve the quantification and interpretation of ventilatory efficiency in athletes, avoiding misinterpretation due to the up-shifting elicited by the usual ⩒E-⩒CO2 slope and ⩒E/⩒CO2 nadir indices, which may be confounded with ventilatory inefficiency. This study suggests that ventilatory changes underpin better ventilatory efficiency during CWR. [ABSTRACT FROM AUTHOR]

Objective: The main objective of this study was to compare lactate thresholds and aerobic capacity from a graded-intensity exercise test (GXT) for near-infrared spectroscopy measurements in healthy, untrained individuals and highly trained athletes. Methods: This study included 29 untrained students (13 females) and 27 highly trained speed skaters (13 females). A maximal effort GXT was performed on a cycloergometer. The lactate-based aerobic and anaerobic thresholds, and the corresponding thresholds for muscle oxygen saturation (SmO2), were determined. Results: The power values determined for all thresholds were significantly higher in female and male speed skaters compared to male and female college students. SmO2 at anaerobic thresholds was significantly lower in female speed skaters than in female students. Both female and male skaters showed greater changes in SmO2 after the GXT compared to students. The recovery did not significantly differ between groups within gender. There was a significant positive correlation in females between the rate of muscle reoxygenation and VO2max power (r = 0.610). In speed skaters, the rate of muscle reoxygenation was not significantly higher than students and correlated positively with VO2max (r = 0.449). Conclusions: The SmO2 at the exercise thresholds, during and after maximal exercise, depends on the training status of the individual. The participants with a higher physical fitness level showed greater decreases in ΔSmO2 at the AT level, as well as after maximal exercise. SmO2 corresponding to the well-established exercise thresholds may be applied to guide training prescription. The rate of muscle reoxygenation after a GXT was also dependent on the aerobic capacity of the participants. [ABSTRACT FROM AUTHOR]

Objective：To evaluate cardiopulmonary exercise fitness in patients with type 2 diabetes mellitus (T2DM) and investigate its influencing factors and possible mechanism. Method：A retrospective analysis was conducted on the medical records of 169 patients with T2DM who underwent cardiopulmonary exercise testing (CPET) from January 2021 to December 2022. Cardiopulmonary fitness was evaluated by peak oxygen consumption（peak VO2)value in CPET. Patients were divided into cardiopulmonary fitness normal group and abnormal group according to peak VO2 % value in CPET．Univariate analysis was used to compare the differences in clinical data between the two groups, and multivariate Logistic regression analysis was used to screen the independent influencing factors to construct risk prediction. Result：A total of 169 cases were included, with 48 cases in the cardiopulmonary fitness normal group and 121 cases in the abnormal group. Multivariate Logistic regression analysis showed that body mass index, history of hypertension, history of heart disease, glycated hemoglobin level, insulin resistance index and physical exercise were independent influencing factors for the exercise fitness in T2DM (OR=1.278, 5.159, 3.876, 2.911, 2.586, 0.086, all P<0.05). Conclusion：Cardiopulmonary fitness is commonly reduced in patients with T2DM. Body mass index, glycated hemoglobin level, insulin resistance index, history of hypertension, history of heart disease are independent risk factors for declined cardiopulmonary fitness. While regular physical exercise is a protective factor. [ABSTRACT FROM AUTHOR]

Purpose: Cardiorespiratory fitness (CRF) is a criticalmarker of overall health and a key predictor of morbidity andmortality, but the existing prediction equations for CRF are primarily derived from general populations and may not be suitable for patients with obesity. Methods: Predicted CRF from different non-exercise prediction equations was compared with measured CRF of patients with obesity who underwent maximal cardiopulmonary exercise testing (CPET). Multiple linear regression was used to develop a population-specific nonexercise CRF prediction model for treadmill exercise including age, sex, weight, height, and physical activity level as determinants. Results: Six hundred sixty patients underwent CPET during the study period. Within the entire cohort, R² values had a range of 0.24 to 0.46. Predicted CRF was statistically different from measured CRF for 19 of the 21 included equations. Only 50% of patients were correctly classified into the measured CRF categories according to predicted CRF. A multiple model for CRF prediction (mL⋅min-1) was generated (R² = 0.78) and validated using two crossvalidation methods. Conclusions: Most used equations provide inaccurate estimates of CRF in patients with obesity, particularly in cases of severe obesity and low CRF. Therefore, a new prediction equation was developed and validated specifically for patients with obesity, offering a more precise tool for clinical CPET interpretation and risk stratification in this population. [ABSTRACT FROM AUTHOR]

The authors discusses the wide availability of analytical procedures for determining exercise physiology thresholds that has led to uncertainty about the method that may offer the highest precision or accuracy for regular testing. They explain the need for a consensus about exercise threshold determination to validate the pioneering physiological models proposed by the research groups of Wildor Hollman and Karlman Wasserman.

Background: Energy expenditure may be difficult to assess when hiking difficult trails. Case presentation: We measured physical activity exercise energy expenditure (PAEE) directly from oxygen uptake using a mobile device (cardiopulmonary exercise testing, CPET), and by using a formula based on heart rate (HR), or metabolic equivalent values from the Compendium of Physical Activity, and other physiological outcomes. Outcomes and implications: Total PAEE (1342 kcal) using CPET showed a two-fold difference between ascending and descending (887 vs. 455 kcal) during a 124-min hike. For HR, PAEE was 1893kcal (+551 kcal overreporting), while compendium-based scenarios ranged from 1179 to 1446 kcal, which was in closer range (−163 to +104 kcal/min) compared to the CPET data. Fluid consumption was 1300 mL/hour, with 1.1% bodyweight loss, peak skin temperature of 35.2°C and core body temperature of 39.2°C. Recommendations: Tables reasonably predict energy expenditure while not precisely reflecting the actual situation. [ABSTRACT FROM AUTHOR]

Background: A knee injury in an athlete leads to periods of forced exercise interruption. Myocardial work (MW) assessed by echocardiographic and cardiopulmonary exercise testing (CPET) are two essential methods for evaluating athletes during the period following injury. However, compared to pre-surgery evaluations, the variations in cardiovascular parameters and functional capacity assessed by these methods after surgery remain unclear. Methods: We evaluated 22 non-professional athletes aged 18–52, involved in prevalently aerobic or alternate aerobic/anaerobic sports activities, who were affected by a knee pathology requiring surgical treatment. The evaluation was performed at rest using transthoracic echocardiography, including MW assessment, and during exercise using CPET. Each athlete underwent the following two evaluations: the first before surgery and the second after surgery (specifically at the end of the deconditioning period). Results: Resting heart rate (HR) increased significantly (from 63.3 ± 10.85 to 71.2 ± 12.52 beats per minute, p = 0.041), while resting diastolic and systolic blood pressure, forced vital capacity, and forced expiratory volume in the first second did not show significant changes. Regarding the echocardiographic data, global longitudinal strain decreased from −18.9 ± 1.8 to −19.3 ± 1.75; however, this reduction was not statistically significant (p = 0.161). However, the global work efficiency (GWE) increased significantly (from 93.0% ± 2.9 to 94.8% ± 2.6, p = 0.006) and global wasted work (GWW) reduced significantly (from 141.4 ± 74.07 to 98.0 ± 50.9, p = 0.007). Additionally, the patients were able to perform maximal CPET at both pre- and post-surgery evaluations, as demonstrated by the peak respiratory exchange ratio and HR. However, the improved myocardial contractility (increased GWE and decreased GWW) observed at rest did not translate into significant changes in exercise parameters, such as peak oxygen consumption and the mean ventilation/carbon dioxide slope. Conclusions: After surgery, the athletes were more deconditioned (as indicated by a higher resting HR) but exhibited better resting myocardial contractility (increased GWE and reduced GWW). Interestingly, no significant changes in exercise capacity parameters, as evaluated by CPET, were found after surgery, suggesting that the improved myocardial contractility was offset by a greater degree of muscular deconditioning. [ABSTRACT FROM AUTHOR]

Transcatheter valve procedures have become a cornerstone in the management of patients with valvular heart disease and high surgical risk, especially for aortic stenosis and mitral and tricuspid regurgitation. Cardiopulmonary exercise testing (CPET) is generally considered the gold standard for objectively quantifying functional capacity, providing a comprehensive evaluation of the human body’s performance, particularly in patients with heart failure (HF). Its accurate assessment is valuable for exploring the pathogenetic mechanisms implicated in HF-related functional impairment. It is also useful for objectively staging the clinical severity and the prognosis of the disease. The improvement in functional capacity after transcatheter valve procedures may be clinically relevant and may provide prognostic information, even in this setting. However, it remains to be fully determined as data on the topic are limited. This review aims to summarize the available evidence on the usefulness of CPET to assess functional improvement in patients undergoing transcatheter valve procedures. [ABSTRACT FROM AUTHOR]

Introduction: Exercise-based cardiac rehabilitation programs (CRPs) represent a multidisciplinary therapeutic approach tailored to improve cardiorespiratory fitness and overall health-related quality of life, while reducing cardiovascular hospitalizations and mortality. Our aim was to determine changes in exercise capacity and cardiac events according to the left ventricular ejection fraction (LVEF) following a CRP. Methods: This single-center cohort study included 131 patients who completed a center-based CRP from 2015 to 2022. Cardiopulmonary exercise testing (CPET), transthoracic echocardiography, and laboratory analysis were performed before and after program completion. Results: Of 232 enrolled patients, 131 were included in our cohort analysis, with 36.6% having a reduced LVEF. These patients exhibited higher rates of atrial fibrillation (p = 0.019) and NT-proBNP values (p < 0.001). Patients with reduced LVEF had lower peak VO2 (pVO2) (p = 0.046), percentage of predicted oxygen consumption (ppVO2) (p < 0.001), and VO2 at anaerobic threshold (p = 0.015) during baseline CPET. Completion of the CRP led to comparable improvements in exercise performance between groups, assessed through Δ pVO2 (p = 0.990), Δ ppVO2 (p = 0.610), and Δ VE/VCO2 slope (p = 0.200). In the study population, male gender and hypertension independently predicted variation in VE/VCO2 slope (p = 0.017) and oxygen uptake efficiency slope (p = 0.048), respectively, post-CRP. During follow-up, 9.2% of all patients had hospital admissions for cardiac events, and 3.8% died, with no significant differences between groups. Conclusion: Patients with reduced LVEF admitted to our CRP showed lower functional status based on specific CPET parameters. After CRP, both reduced and preserved LVEF groups experienced similar functional improvements. Therefore, strategies to increase participation of patients with reduced LVEF in such programs are warranted. [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]

Objective: To observe the effects of cardiac rehabilitation guided by cardiopulmonary exercise testing (CPET) on cardiorespiratory reserve function, blood pressure, blood pressure variability, and lipid metabolism in patients with hypertension. Methods: A randomized trial enrolled 67 Grade 1 hypertensive patients on antihypertensive drugs, divided into conventional (n = 35) and CPET (n = 32) groups. Antihypertensive drugs were not adjusted in both groups during the study period. Blood pressure, cardiorespiratory indicators, lipid profile, and BMI were assessed pre/post 12 weeks. Results: Postintervention, the CPET group exhibited significantly lower blood pressure levels and improved cardiac indicators compared to the conventional group (p < 0.05). CPET group showed greater improvements in cardiorespiratory endurance indicators (p < 0.05). The cardiorespiratory endurance indicators showed significantly greater increases in the CPET group compared to the conventional group (p < 0.05). Low‐density lipoprotein cholesterol (LDL‐C), total cholesterol (TC), triglycerides (TG), and body mass index (BMI) were significantly lower in the CPET group (p < 0.05). Conclusion: In addition to drug treatment, cardiac rehabilitation guided by CPET can effectively improve blood pressure control, reduce blood pressure variability, improve cardiorespiratory function and lipid metabolism, and increase exercise endurance in patients with Grade 1 hypertension. Its efficacy is clear and safe, with clinical value for promotion. [ABSTRACT FROM AUTHOR]

Background: After COVID-19 infection, 10–20% of patients suffer from varying symptoms lasting more than 12 weeks (Long COVID, LC). Exercise intolerance and fatigue are common in LC. The aim was to measure the maximal exercise capacity of the LC patients with these symptoms and to analyze whether this capacity was related to heart rate (HR) responses at rest and during exercise and recovery, to find out possible sympathetic overactivity, dysautonomia or chronotropic incompetence. Methods: Cardiopulmonary exercise test was conducted on 101 LC patients, who were admitted to exercise testing. The majority of them (86%) had been treated at home during their acute COVID-19 infection. Peak oxygen uptake (VO2peak), maximal power during the last 4 min of exercise (Wlast4), HRs, and other exercise test variables were compared between those with or without subjective exercise intolerance, fatigue, or both. Results: The measurements were performed in mean 12.7 months (SD 5.75) after COVID-19 infection in patients with exercise intolerance (group EI, 19 patients), fatigue (group F, 31 patients), their combination (group EI + F, 37 patients), or neither (group N, 14 patients). Exercise capacity was, in the mean, normal in all symptom groups and did not significantly differ among them. HRs were higher in group EI + F than in group N at maximum exercise (169/min vs. 158/min, p = 0.034) and 10 min after exercise (104/min vs. 87/min, p = 0.028). Independent of symptoms, 12 patients filled the criteria of dysautonomia associated with slightly decreased Wlast4 (73% vs. 91% of sex, age, height, and weight-based reference values p = 0.017) and 13 filled the criteria of chronotropic incompetence with the lowest Wlast4 (63% vs. 93%, p < 0.001), VO2peak (70% vs. 94%, p < 0.001), the lowest increase of systolic blood pressure (50 mmHg vs. 67 mmHg, p = 0.001), and the greatest prevalence of slight ECG-findings (p = 0.017) compared to patients without these features. The highest prevalence of chronotropic incompetence was seen in the group N (p = 0.022). Conclusions: This study on LC patients with different symptoms showed that cardiopulmonary exercise capacity was in mean normal, with increased sympathetic activity in most patients. However, we identified subgroups with dysautonomia or chronotropic incompetence with a lowered exercise capacity as measured by Wlast4 or VO2peak. Subjective exercise intolerance and fatigue poorly foresaw the level of exercise capacity. The results could be used to plan the rehabilitation from LC and for selection of the patients suitable for it. [ABSTRACT FROM AUTHOR]

Objective: Construction nomogram was to effectively predict long‐term prognosis in patients with non‐small cell lung cancer (NSCLC). Materials and Methods: The nomogram is developed by a retrospective study of 347 patients with NSCLC who underwent cardiopulmonary exercise testing (CPET) before surgery from May 2019 to February 2022. Cross‐validation divided the data into a training cohort and validation cohort. The discrimination and accuracy ability of the nomogram were proofed by concordance index (C‐index), calibration curve, receiver operating characteristic (ROC) curve, the area under the curve (AUC), and time‐dependent ROC in validation cohort. Results: Age, intraoperative blood loss, VO2 peak, and VE/VCO2 slope were included in the model of nomogram. The model demonstrated good discrimination and accuracy with C‐index of 0.770 (95% CI: 0.712–0.822). AUC of 6 (AUC: 0.789, 95% CI: 0.726–0.851) and 12 months (AUC: 0.787, 95% CI: 0.724–0.850) were shown in ROC. Time‐independent ROC maintains a good effect within 12 months. Conclusion: We developed a nomogram based on CPET. This model has a good ability of discrimination and accuracy. It could help clinicians to make treatment decision in clinical decision. [ABSTRACT FROM AUTHOR]

The exercise capacity long after repair of tetralogy of Fallot, when performed exclusively with a transatrial repair, is unclear. It is also unknown whether echocardiography and cardiopulmonary exercise testing can predict the risk of reoperation in this patient group. We retrospectively reviewed the clinical records of 59 patients who underwent cardiopulmonary exercise testing after transatrial Fallot repair at a single centre. Patients underwent cardiopulmonary exercise testing at a mean age of 16.6±4.4 years, and at 15.3±4.1 years after Fallot repair. At testing, the volume of oxygen consumption at maximal exercise (VO 2 max) was 71%±13% and the oxygen pulse was 80%±17% of predicted values. Seventeen (17) patients (29%) had a VO 2 max superior to 80% of the predicted value. Thirty-two (32) patients (56%) had severe pulmonary regurgitation, three (5%) had moderate pulmonary regurgitation, and 12 (21%) had mild pulmonary regurgitation. After a mean of 7.8±3.9 years following cardiopulmonary exercise testing (23±5.3 years after the repair), 21 (40%) patients underwent reoperation. Right ventricular dilation and systolic function on echocardiography were both significantly associated with subsequent reoperation rates. Patients who had severe right ventricular dilation were eight times more likely to undergo subsequent reoperation (hazard ratio 8.67; 1.82–41.3; p=0.007). No cardiopulmonary exercise testing variable independently predicted reoperation. The exercise capacity at adolescence following transatrial repair of tetralogy of Fallot is maintained at around 70% of predicted values. Only the patients with normal right ventricular size and normal right ventricular function seemed to be protected from reoperation over the subsequent decade. We found no exercise variables which predicted reoperation. [ABSTRACT FROM AUTHOR]

Summary: The goal of this study is to quantify the assumptions associated with the Wasserman‐Hansen (WH) and Fitness Registry and the Importance of Exercise: A National Database (FRIEND) predictive peak oxygen consumption (pVO2) equations across body mass index (BMI). Assumptions in pVO2 for both equations were first determined using a simulation and then evaluated using exercise data from the Stanford Exercise Testing registry. We calculated percent‐predicted VO2 (ppVO2) values for both equations and compared them using the Bland–Altman method. Assumptions associated with pVO2 across BMI categories were quantified by comparing the slopes of age‐adjusted VO2 ratios (pVO2/pre‐exercise VO2) and ppVO2 values for different BMI categories. The simulation revealed lower predicted fitness among adults with obesity using the FRIEND equation compared to the WH equations. In the clinical cohort, we evaluated 2471 patients (56.9% male, 22% with BMI >30 kg/m2, pVO2 26.8 mlO2/kg/min). The Bland–Altman plot revealed an average relative difference of −1.7% (95% CI: −2.1 to −1.2%) between WH and FRIEND ppVO2 values with greater differences among those with obesity. Analysis of the VO2 ratio to ppVO2 slopes across the BMI spectrum confirmed the assumption of lower fitness in those with obesity, and this trend was more pronounced using the FRIEND equation. Peak VO2 estimations between the WH and FRIEND equations differed significantly among individuals with obesity. The FRIEND equation resulted in a greater attributable reduction in pVO2 associated with obesity relative to the WH equations. The outlined relationships between BMI and predicted VO2 may better inform the clinical interpretation of ppVO2 values during cardiopulmonary exercise test evaluations. [ABSTRACT FROM AUTHOR]

Cardiopulmonary exercise testing (CPET) provides clinicians with information vital to the management of pediatric cardiology patients. CPET can also be used to measure cardiorespiratory fitness (CRF) in these patients. CRF is a robust marker of overall health in children. However, a complete understanding of CRF in pediatric cardiology patients is limited by lack of large, standardized CPET databases. Our purpose was to develop a standardized CPET database, describe available data at our institution, and discuss challenges and opportunities associated with this project. CPETs performed from 1993 to present in an urban pediatric hospital were collected and compiled into a research database. Historical data included demographic and clinical variables and CPET outcomes, and additional variables were calculated and coded to facilitate analyses in these cohorts. Patient diagnoses were coded to facilitate sub-analyses of specific cohorts. Quality assurance protocols were established to ensure future database contributions and promote inter-institutional collaborations. This database includes 10,319 CPETs (56.1% male), predominantly using the Bruce Protocol. Patients ranging from ages 6 to 18 years comprise 86.8% of available CPETs. Diagnosis classification scheme includes patients with structurally normal hearts (n = 3,454), congenital heart disease (n = 3,614), electrophysiological abnormalities (n = 2,082), heart transplant or cardiomyopathy (n = 833), and other diagnoses (n = 336). Historically, clinicians were provided with suboptimal interpretive resources for CPET, often generalizing inferences from these resources to non-representative clinical populations. This database supports representative CRF comparisons and establishes a framework for future CRF-based registries in pediatric patients referred for CPET, ultimately improving clinical decision-making regarding fitness in these populations. [ABSTRACT FROM AUTHOR]

Background: The US Department of Labor (DOL) does not fund diffusing capacity (DLCO) or metabolic measurements from cardiopulmonary exercise testing (CPET) for coal miners' disability evaluations. Although exercise arterial blood gas testing is covered, many miners are unable to perform maximal tests, and sampling at peak exercise can be challenging. We explored the relationship between resting DLCO, radiographic disease severity, and CPET abnormalities in former US coal miners. Methods: We analyzed data from miners evaluated between 2005 and 2015. Multivariable linear and logistic regression analyses were used to examine relationships between percent predicted (pp) forced expiratory volume in 1 s (FEV1pp), DLCOpp, VO2maxpp, A‐a oxygen gradient (A‐a)pp, dead space fraction (Vd/Vt), disabling oxygen tension (PO2), and radiographic findings of pneumoconiosis. Results: Data from 2015 male coal miners was analyzed. Mean tenure was 28 years (SD 8.6). Thirty‐twopercent had an abnormal A‐a gradient (>150 pp), 20% had elevated Vd/Vt (>0.33), and 34% a VO2max < 60 pp. DLCOpp strongly predicted a disabling PO2, with an odds ratio (OR) of 2.33 [2.09−2.60], compared to 1.18 [1.08−1.29] for FEV1. Each increase in subcategory of small opacity (simple) pneumoconiosis increased the odds of a disabling PO2 by 42% [1.29−1.57], controlling for age, body mass index, pack‐years of tobacco smoke exposure, and years of coal mine employment. Conclusions: DLCO is the best resting pulmonary function test predictor of CPET abnormalities. Radiographic severity of pneumoconiosis was also associated with CPET abnormalities. These findings support funding DLCO testing for impairment and suggest the term "small opacity" should replace "simple" pneumoconiosis to reflect significant associations with impairment. [ABSTRACT FROM AUTHOR]

Background: Endurance athletes (EA) are an emerging population of focus for cardiovascular health. The oxygen uptake efficiency plateau (OUEP) is the levelling-off period of ratio between oxygen uptake (VO2) and ventilation (VE). In the cohort of EA, we externally validated prediction models for OUEP and derived with internal validation a new equation. Methods: 140 EA underwent a medical assessment and maximal cycling cardiopulmonary exercise test. Participants were 55% male (N = 77, age = 21.4 ± 4.8 years, BMI = 22.6 ± 1.7 kg·m− 2, peak VO2 = 4.40 ± 0.64 L·min− 1) and 45% female (N = 63, age = 23.4 ± 4.3 years, BMI = 22.1 ± 1.6 kg·m− 2, peak VO2 = 3.21 ± 0.48 L·min− 1). OUEP was defined as the highest 90-second continuous value of the ratio between VO2 and VE. We used the multivariable stepwise linear regression to develop a new prediction equation for OUEP. Results: OUEP was 44.2 ± 4.2 mL·L− 1 and 41.0 ± 4.8 mL·L− 1 for males and females, respectively. In external validation, OUEP was comparable to directly measured and did not differ significantly. The prediction error for males was − 0.42 mL·L− 1 (0.94%, p = 0.39), and for females was + 0.33 mL·L− 1 (0.81%, p = 0.59). The developed new prediction equation was: 61.37–0.12·height (in cm) + 5.08 (for males). The developed model outperformed the previous. However, the equation explained up to 12.9% of the variance (R = 0.377, R2 = 0.129, RMSE = 4.39 mL·L− 1). Conclusion: OUEP is a stable and transferable cardiorespiratory index. OUEP is minimally affected by fitness level and demographic factors. The predicted OUEP provided promising but limited accuracy among EA. The derived new model is tailored for EA. OUEP could be used to stratify the cardiorespiratory response to exercise and guide training. [ABSTRACT FROM AUTHOR]

Background and Objectives: Obstructive sleep apnea (OSA) is common in cardiovascular disease (CVD), although positive airway pressure (PAP) treatment has not been demonstrated to improve the cardiovascular outcome. The objective of this study is to investigate the impact of adherence to PAP therapy on cardiopulmonary exercise testing (CPET) performance in patients with concomitant OSA and CVD. Materials and Methods: This preliminary study involved symptomatic OSA patients requiring PAP treatment who had CVD. All subjects underwent polysomnography, echocardiography, and CPET at baseline. After 6 to 12 months of PAP treatment, CPET performance was re-assessed. The changes in CPET parameters before and after PAP treatment were compared between patients who were adherent to PAP and patients who were not adherent to PAP. Results: A total of 16 OSA patients with an apnea–hypopnea index of 32.0 ± 23.4 were enrolled. Patients were classified into the adherent (n = 9) and non-adherent (n = 7) groups with regard to PAP adherence. After 6 to 12 months of PAP treatment, the PAP-adherent group showed a greater increase in peak VO2 than the PAP-non-adherent group, but the difference between the two groups was not significant (p = 0.581). The decrease in ventilatory equivalent for the carbon dioxide slope (VE/VCO2) was significantly greater in the PAP-adherent group compared to the PAP-non-adherent group (p = 0.030). Conclusions: Adherence to PAP therapy for OSA is associated with an improvement in the VE/VCO2 slope, as an index of the ventilatory response to exercise, in patients with CVD. Screening for sleep apnea in CVD patients may be warranted, and strategies to optimize adherence to PAP in these patients are beneficial. Further evidence is needed to elucidate whether CPET could be routinely used to monitor treatment responses of OSA to PAP therapy in patients with CVD. [ABSTRACT FROM AUTHOR]

BackgroundMechanisms underlying persistent cardiopulmonary symptoms after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection (postacute sequelae of coronavirus disease 2019 [COVID-19; PASC] or "long COVID") remain unclear. This study sought to elucidate mechanisms of cardiopulmonary symptoms and reduced exercise capacity.MethodsWe conducted cardiopulmonary exercise testing (CPET), cardiac magnetic resonance imaging (CMR) and ambulatory rhythm monitoring among adults >1 year after SARS-CoV-2 infection, compared those with and those without symptoms, and correlated findings with previously measured biomarkers.ResultsSixty participants (median age, 53 years; 42% female; 87% nonhospitalized; median 17.6 months after infection) were studied. At CPET, 18/37 (49%) with symptoms had reduced exercise capacity (1 year after COVID-19 were associated with reduced exercise capacity, which was associated with earlier inflammatory markers. Chronotropic incompetence may explain exercise intolerance among some with "long COVID."

BackgroundIndexing peak oxygen uptake (VO2peak) to total body mass can underestimate cardiorespiratory fitness (CRF) in women, older adults, and individuals with obesity. The primary objective of this multicenter study was to derive and validate a body size-independent scaling metric for VO2peak. This metric was termed exercise body mass (EBM).MethodIn a cohort of apparently healthy individuals from the Fitness Registry and the Importance of Exercise National Database, we derived EBM using multivariable log-normal regression analysis. Subsequently, we developed a novel workload (WL) equation based on speed (Sp), fractional grade (fGr), and heart rate reserve (HRR). The generalized equation for VO2peak can be expressed as VO2peak = Cst × EBM × WL, where Cst is a constant representing the VO2peak equivalent of one metabolic equivalent of task. This generalized equation was externally validated using the Stanford exercise testing (SET) dataset.ResultsA total of 5,618 apparently healthy individuals with a respiratory exchange ratio >1.0 (57% men, mean age 44 ± 13 years) were included. The EBM was expressed as Mass (kg)0.63 × Height (m)0.53 × 1.16 (if a man) × exp (−0.39 × 10−4 × age2), which was also approximated using simple sex-specific additive equations. Unlike total body mass, EBM provided body size-independent scaling across both sexes and WL categories. The generalized VO2peak equation was expressed as 11 × EBM × [2 + Sp (in mph) × (1.06 + 5.22 × fGr) + 0.019 × HRR] and had an R2 of 0.83, p

Introduction: Assessment of exercise capacity by cardiopulmonary exercise testing (CPET) in adults with congenital heart disease (CHD) is important for prognostication and preoperative assessment. Peak oxygen uptake (PVO2) is used commonly, but can be challenging due to the difficulties of undertaking maximal CPET testing in this population. We explored whether oxygen uptake efficiency slope (OUES) at ventilatory anaerobic threshold (VAT), the point during CPET at which OUES becomes strongly correlated with PVO2, and is more reliably available from submaximal CPET, can predict PVO2 in adults with CHD. Methods: We assessed consecutive individuals who completed maximal CPET at our cardiorespiratory centre, as part of routine service review, between March 2019 and August 2021, recording data such as PVO2, VAT and OUES at various proportions of a maximal test (75 %, 90 %, 100 %, and VAT). We employed linear regression modelling to analyse the association between PVO2 and OUES at VAT, and subsequently create an equation to predict PVO2 from OUES at VAT. Parametric data are presented using Pearson's correlation coefficient and non-parametric data using Spearman's rho. Results: We analysed 391 individuals (177 female, age 32 ± 11 years). Mean ± SD PVO2 was 23.3 ± 6.86 ml/min/kg or 1724 ± 540 ml/min, peak VE 86.7 ± 25.4 l/min. The point of VAT as a percentage of PVO2 achieved was 66.5 ± 9.4 %, and VAT as a percentage of predicted PVO2 46.9 ± 11.4 %. PVO2 was correlated with OUES at 100 % (R = 0.91, P