Differences In Exercise Capacity Research Articles

Differences in exercise capacity and muscle glycogen metabolism in C57BL/6J and BALB/cA mice.

This study compared differences in exercise capacity as well as muscle glycogen content and degradation, and mitochondrial enzyme activity between C57BL/6J and BALB/cA mice. In exercise tests, grip strength was higher in BALB/cA mice. In Rotarod and Inverted screen test, C57BL/6J mice had significantly longer exercise durations and showed differences in motor function and muscle endurance time. Glycogen in the liver and muscle of C57BL/6J mice was significantly decreased after 20 min of swimming. Muscle glycogen content in BALB/cA mice was higher than in C57BL/6J, but swimming induced no decrease in glycogen content. Glycogen phosphorylase in muscle was inactive in the absence of AMP, and its activity increased in a concentration-dependent manner with the addition of AMP in C57BL/6J mice. In BALB/cA mice, phosphorylase activity was increased by AMP, but not further increased by higher concentrations of AMP. The citrate synthase activity in muscle did not differ between C57BL/6J and BALB/cA mice. The results of this study suggested that the reactivity of muscle glycogen phosphorylase to AMP differs among strains of mice and affects glycogen availability during exercise.

Iron deficiency in heart failure with preserved ejection fraction: rationale and design of the FAIR-HFpEF trial

Background: Iron deficiency is highly prevalent in patients with heart failure and has well established diagnostic criteria. Its occurrence is associated with reduced quality of life, exercise capacity and increased hospitalization rates and mortality. The clinical efficacy of treating iron deficiency has not been tested in patients with heart failure with preserved ejection fraction (HFpEF). Methods: The FAIRHFpEF trial aims to enroll patients with HFpEF, reduced exercise capacity and iron deficiency (defined as serum ferritin <100 ng/mL or serum ferritin 100299 ng/mL with transferrin saturation <20%). Patients will be treated in a multicenter, doubleblind, randomized clinical trial with intravenous ferric carboxymaltose (FCM) at doses aimed to replenish iron stores vs. placebo. The primary endpoint is the difference in exercise capacity from baseline to week 24 as assessed by the 6minute walk test. Secondary endpoints include healthrelated quality of life assessments such as the Kansas City Cardiomyopathy Questionnaire, the European Quality of Life5 Dimensions questionnaire and global function tests. Conclusions: The FAIRHFpEF trial is designed to investigate the effect of intravenous iron repletion in iron deficient patients with HFpEF using FCM.

Iron deficiency in heart failure with preserved ejection fraction: rationale and design of the FAIR-HFpEF trial

Background: Iron deficiency is highly prevalent in patients with heart failure and has well established diagnostic criteria. Its occurrence is associated with reduced quality of life, exercise capacity and increased hospitalization rates and mortality. The clinical efficacy of treating iron deficiency has not been tested in patients with heart failure with preserved ejection fraction (HFpEF). Methods: The FAIRHFpEF trial aims to enroll patients with HFpEF, reduced exercise capacity and iron deficiency (defined as serum ferritin <100 ng/mL or serum ferritin 100299 ng/mL with transferrin saturation <20%). Patients will be treated in a multicenter, doubleblind, randomized clinical trial with intravenous ferric carboxymaltose (FCM) at doses aimed to replenish iron stores vs. placebo. The primary endpoint is the difference in exercise capacity from baseline to week 24 as assessed by the 6minute walk test. Secondary endpoints include healthrelated quality of life assessments such as the Kansas City Cardiomyopathy Questionnaire, the European Quality of Life5 Dimensions questionnaire and global function tests. Conclusions: The FAIRHFpEF trial is designed to investigate the effect of intravenous iron repletion in iron deficient patients with HFpEF using FCM.

Iron deficiency in heart failure with preserved ejection fraction: rationale and design of the FAIR-HFpEF trial

Background: Iron deficiency is highly prevalent in patients with heart failure and has well established diagnostic criteria. Its occurrence is associated with reduced quality of life, exercise capacity and increased hospitalization rates and mortality. The clinical efficacy of treating iron deficiency has not been tested in patients with heart failure with preserved ejection fraction (HFpEF). Methods: The FAIRHFpEF trial aims to enroll patients with HFpEF, reduced exercise capacity and iron deficiency (defined as serum ferritin <100 ng/mL or serum ferritin 100299 ng/mL with transferrin saturation <20%). Patients will be treated in a multicenter, doubleblind, randomized clinical trial with intravenous ferric carboxymaltose (FCM) at doses aimed to replenish iron stores vs. placebo. The primary endpoint is the difference in exercise capacity from baseline to week 24 as assessed by the 6minute walk test. Secondary endpoints include healthrelated quality of life assessments such as the Kansas City Cardiomyopathy Questionnaire, the European Quality of Life5 Dimensions questionnaire and global function tests. Conclusions: The FAIRHFpEF trial is designed to investigate the effect of intravenous iron repletion in iron deficient patients with HFpEF using FCM.

Abstract 13847: Biomarker-Based Phenomapping in Chronic Stable HFpEF and Exercise Capacity: An Analysis of the RELAX Trial

Introduction: Heart failure with preserved ejection fraction (HFpEF) is a heterogenous disease associated with low exercise capacity. Hypothesis: Unsupervised clustering of biomarker data can identify subgroups of individuals with HFpEF and differences in exercise capacity. Methods: The study included participants with chronic, stable HFpEF from the RELAX trial with available serum biomarker data. We used unsupervised hierarchical clustering analysis of 9 serum biomarkers to derive phenogroups of participants with HFpEF. Adjusted linear regression was used to assess the association between cluster membership with peak oxygen consumption (VO2), maximum exercise watts, and VO2 anaerobic threshold. Results: Among 211 participants in the RELAX trial, 3 phenogroups were identified based on the gain in within-inertia. No significant differences were observed in age, sex, or race across phenogroups. Phenogroup 1 (n=136) participants had the lowest burden of CV (cardiovascular) risk factors, including diabetes, anemia, and kidney disease as well as the lowest overall biomarkers levels ( Fig. A ). Phenogroup 2 (n=61) consisted of participants who were older with a higher burden of CV risk factors and fibrosis biomarkers, including galectin-3, collagen-I, and troponin-I levels. Phenogroup 3 (n=14) participants were younger with high burden of CV risk factors and inflammatory biomarkers including aldosterone, CRP, and uric acid. Compared with phenogroup 1, phenogroup 2 and 3 had significantly lower peak VO2, adjusted for traditional CV risk factors [estimate (95% CI): -1.99 (-2.83, -1.16) and -2.31 (-3.66, -0.95), respectively] (Fig. B ). Additionally, phenogroup 3 vs. 1 had lower exercise watts and VO2 anaerobic threshold. Conclusion: Using serum biomarkers, we identified 3 unique phenogroups of patients with chronic, stable HFpEF and significant differences in CV risk factor burden and exercise capacity.

The molecular athlete: exercise physiology from mechanisms to medals.

Human skeletal muscle demonstrates remarkable plasticity, adapting to numerous external stimuli including the habitual level of contractile loading. Accordingly, muscle function and exercise capacity encompass a broad spectrum, from inactive individuals with low levels of endurance and strength to elite athletes who produce prodigious performances underpinned by pleiotropic training-induced muscular adaptations. Our current understanding of the signal integration, interpretation, and output coordination of the cellular and molecular mechanisms that govern muscle plasticity across this continuum is incomplete. As such, training methods and their application to elite athletes largely rely on a "trial-and-error" approach, with the experience and practices of successful coaches and athletes often providing the bases for "post hoc" scientific enquiry and research. This review provides a synopsis of the morphological and functional changes along with the molecular mechanisms underlying exercise adaptation to endurance- and resistance-based training. These traits are placed in the context of innate genetic and interindividual differences in exercise capacity and performance, with special consideration given to aging athletes. Collectively, we provide a comprehensive overview of skeletal muscle plasticity in response to different modes of exercise and how such adaptations translate from "molecules to medals."

Pulmonary endarterectomy and balloon pulmonary angioplasty in chronic thromboembolic pulmonary hypertension: Comparison of changes in hemodynamics and functional capacity.

The treatment of choice for chronic thromboembolic pulmonary hypertension (CTEPH) is pulmonary endarterectomy (PEA). Balloon pulmonary angioplasty (BPA) is an emerging option for inoperable patients. Comparisons of the hemodynamic and functional outcome between these treatments are scarce. In this single-center observational cohort study, we compared hemodynamics by right heart catheterization and peak oxygen consumption before and 5 months (±14 days) after either PEA or BPA. Comprehensive evaluation and selection for PEA or BPA was performed by an expert CTEPH team. Fourty-twoand fourty consecutive patients were treated with PEA or BPA, respectively. Demographics were similar between groups. Both PEA and BPA significantly reduced mean pulmonary artery pressure (from 46 ± 11 mmHg at baseline to 28 ± 13 mmHg at follow-up; p < 0.001 and from 43 ± 12 mmHg to 31 ± 9 mmHg; p < 0.001) and pulmonary vascular resistance (from 686 ± 347 dyn s cm-5 at baseline to 281 ± 197 dyn s cm-5 at follow-up; p < 0.001 and from 544 ± 322 dyn s cm-5 to 338 ± 180 dyn s cm-5; p < 0.001), with significantly lower reductions for both parameters in the former group. However, cardiopulmonary exercise testing revealed no significant between group differences in exercise capacity. Diffusion capacity for carbon monoxide at baseline was the only follow-up predictor for peak VO2. In our study, PEA reduced pulmonary pressures more than BPA did, but similar improvements were observed for exercise capacity. Thus, while long term data after BPA is lacking, BPA treated CTEPH patients can expect physical gains in line with PEA.

Abstract 15439: Longitudinal Assessment of Racial Differences in Exercise Capacity After Breast Cancer Treatment: WF-97415

Introduction: Breast cancer (BC) treatment toxicity contributes to elevated rates of cardiovascular morbidities, such as reduced exercise capacity, a risk factor for long-term cardiovascular disease (CVD) and mortality. Past studies have shown that Black women experience greater cardiotoxicity after BC treatment than white women. No studies have investigated racial differences in exercise capacity. The lack of longitudinal data leaves uncertainty as to whether greater declines in exercise capacity are experienced by Black BC survivors. Methods: This cohort was comprised of 236 women with stage I-III BC (80% white; 20% Black) and 130 cancer-free controls in the UPBEAT (NCT02791581) and DETECT (NCT01719562) studies. Submaximal exercise capacity was obtained via 6-Minute Walk Distance (6MWD, meters [m]) at baseline (pre-treatment) and 3 months. Linear regression was used to examine associations of race with baseline 6MWD and changes in 6MWD. Results: Mean age [SD] of BC survivors was 55.7 [10.9] years. Mean [SD] total meters walked pre-treatment was lower in Black women with BC (423 m [81.0]) than white women with BC (475 m [87.7]; p=0.01), and lower than Black women without BC (471 m [76.9]; p=0.07). Black BC survivors experienced a greater mean decline from baseline to 3-months in 6MWD (30 m [68.5]) than white BC survivors (21.7 m [86.6]; Table 1; p=0.02) or Black women without BC (9.2 m [67.3]; p=0.001), translating to a mean difference of 60 m between Black and white BC survivors during BC treatment. Conclusions: This is the first study to suggest racial differences in submaximal exercise capacity during BC treatment. Black BC survivors experienced a greater reduction in exercise capacity than white BC survivors after cancer treatment as early as 3-months post-diagnosis. This clinically-meaningful difference in exercise capacity warrants further investigation, particularly to determine interventions to reverse the loss of exercise capacity.

Abstract 12889: Sex Differences in Exercise Capacity After Home-Based Cardiac Rehabilitation During the Covid-19 Pandemic

Introduction: Many center-based cardiac rehabilitation programs were forced to close during the pandemic resulting in a programmatic shift to delivering cardiac rehabilitation remotely in the home-based setting. This study examined sex differences in the change of exercise frequency and exercise capacity in patients participating in home-based cardiac rehabilitation (HBCR) during the COVID-19 pandemic. Methods: Retrospective cohort study of 567 HBCR patients between March 2020 and May 2021. Patients who completed the Duke Activity Status Index questionnaire before and after HBCR were included. We calculated the number of reported exercise days/ week, exercise min/day, and VO 2 peak estimated. Patients were divided into two groups according to sex (Male/Female). Continuous data are described as mean±SD and baseline data compared with a two-sample t-test. The delta change from pre-post between groups also are compared with a two-sample t-test. Results: Of 567 HBCR patients, 118 patients completed both pre and post HBCR questionnaires (Male, n=82, 66±12 yo vs Female, n=36, 65±12 yo, p=0.80). There were no differences between groups for baseline exercise days/week or exercise min/day pre HBCR (4.0±2.8 vs 4.1±3.0 days, p=0.87; 22±20 vs 18±20 min, p=0.33); however, VO 2 peak at baseline HBCR was higher in males than females (22.3±8.1 vs 18.9±5.9 ml/kg/min, p&lt;0.05). Both groups improved exercise days/week (4.0±2.8 to 5.7±1.5 vs 4.1±3.0 to 5.7±1.4 days, p&lt;0.05 for both), exercise min/day (22±20 to 40±15 vs 18±20 to 37±21 min, p&lt;0.05 for both), and VO 2 peak (22.3±8.1 to 27.8±8.0 vs 18.9±5.9 to 22.7±6.5, ml/kg/min, p&lt;0.05 for both). In addition, there was no significant difference for the delta change of the three outcomes between groups (1.7±2.7 vs 1.6±2.5 days; 18±19 vs 19±18 min; 5.5±6.5 vs 3.8±4.5 ml/min/kg, p&gt;0.05 for all). Conclusions: Female patients entering HBCR during the COVID-19 pandemic demonstrated lower exercise capacity compared to males; however, both female and male patients increased exercise frequency (days/week and min/day) and exercise capacity (estimated VO 2 peak) similarly after attending HBCR during the COVID-19 pandemic.

Use of Cardiopulmonary Exercise Testing to Evaluate Long COVID-19 Symptoms in Adults

Reduced exercise capacity is commonly reported among individuals with COVID-19 symptoms more than 3 months after SARS-CoV-2 infection (long COVID-19 [LC]). Cardiopulmonary exercise testing (CPET) is the criterion standard to measure exercise capacity and identify patterns of exertional intolerance. To estimate the difference in exercise capacity among individuals with and without LC symptoms and characterize physiological patterns of limitations to elucidate possible mechanisms of LC. A search of PubMed, EMBASE, Web of Science, preprint servers, conference abstracts, and cited references was performed on December 20, 2021, and again on May 24, 2022. A preprint search of medrxiv.org, biorxiv.org, and researchsquare.com was performed on June 9, 2022. Studies of adults with SARS-CoV-2 infection more than 3 months earlier that included CPET-measured peak oxygen consumption (V̇o2) were screened independently by 2 blinded reviewers; 72 (2%) were selected for full-text review, and 35 (1%) met the inclusion criteria. An additional 3 studies were identified from preprint servers. Data extraction was performed by 2 independent reviewers according to the PRISMA reporting guideline. Data were pooled using random-effects models. Difference in peak V̇o2 (in mL/kg/min) among individuals with and without persistent COVID-19 symptoms more than 3 months after SARS-CoV-2 infection. A total of 38 studies were identified that performed CPET on 2160 individuals 3 to 18 months after SARS-CoV-2 infection, including 1228 with symptoms consistent with LC. Most studies were case series of individuals with LC or cross-sectional assessments within posthospitalization cohorts. Based on a meta-analysis of 9 studies including 464 individuals with LC symptoms and 359 without symptoms, the mean peak V̇o2 was -4.9 (95% CI, -6.4 to -3.4) mL/kg/min among those with symptoms with a low degree of certainty. Deconditioning and peripheral limitations (abnormal oxygen extraction) were common, but dysfunctional breathing and chronotropic incompetence were also described. The existing literature was limited by small sample sizes, selection bias, confounding, and varying symptom definitions and CPET interpretations, resulting in high risk of bias and heterogeneity. The findings of this systematic review and meta-analysis study suggest that exercise capacity was reduced more than 3 months after SARS-CoV-2 infection among individuals with symptoms consistent with LC compared with individuals without LC symptoms, with low confidence. Potential mechanisms for exertional intolerance other than deconditioning include altered autonomic function (eg, chronotropic incompetence, dysfunctional breathing), endothelial dysfunction, and muscular or mitochondrial pathology.

Influence of bronchopulmonary dysplasia on lung function in adolescents who were born extremely prematurely.

To assess if a previous diagnosis of bronchopulmonary dysplasia(BPD) was associated with poorer lung function at 16 to 19 years of age, regardless of whether postnatal corticosteroids had been administered. Infants with BPD will have poorer lung function at 16 to 19 years of age. Prospective follow-up study. One hundred and sixty-one participants aged between 16 and 19 years who were born at less than 29 weeks of gestation; 87 had had BPD. Lung function was assessed by spirometry (FEV1 , FVC, FEV1 /FVC, FEF75 , FEF50 , FEF25 , FEF25 -75 , PEF), impulse oscillometry (R5Hz and R20Hz), plethysmography (FRCpleth , TLCpleth , RVpleth ), diffusion capacity of the lungs for carbon monoxide (DL CO, DL CO/VA) and lung clearance index (LCI). Questionnaires were used to quantify respiratory symptoms and a shuttle sprint test to assess exercise capacity. At 16 to 19 years, those who had had a diagnosis of BPD had poorer airway function (FEV1 , FEF75 , FEF50 , FEF25 -75 ) compared to those without. FVC and DL CO were also poorer in those who had BPD. Those differences remained significant after adjusting for sex, gestational age, and maternal smoking. When excluding those who had received postnatal corticosteroids, differences remained significant in FEV1 , FVC, and FEF75 . There were no significant differences in exercise capacity or respiratory symptoms between those with and without BPD. In adolescents and young adults born prematurely, those who had BPD had poorer lung function compared to those without, regardless of whether they had received postnatal corticosteroids.

Effectiveness of home-based pulmonary rehabilitation: systematic review and meta-analysis.

Despite proven effectiveness for people with chronic respiratory diseases, practical barriers to attending centre-based pulmonary rehabilitation (centre-PR) limit accessibility. We aimed to review the clinical effectiveness, components and completion rates of home-based pulmonary rehabilitation (home-PR) compared to centre-PR or usual care. Using Cochrane methodology, we searched (January 1990 to August 2021) six electronic databases using a PICOS (population, intervention, comparison, outcome, study type) search strategy, assessed Cochrane risk of bias, performed meta-analysis and narrative synthesis to answer our objectives and used the Grading of Recommendations, Assessment, Development and Evaluations framework to rate certainty of evidence. We identified 16 studies (1800 COPD patients; 11 countries). The effects of home-PR on exercise capacity and/or health-related quality of life (HRQoL) were compared to either centre-PR (n=7) or usual care (n=8); one study used both comparators. Compared to usual care, home-PR significantly improved exercise capacity (standardised mean difference (SMD) 0.88, 95% CI 0.32-1.44; p=0.002) and HRQoL (SMD -0.62, 95% CI -0.88--0.36; p<0.001). Compared to centre-PR, home-PR showed no significant difference in exercise capacity (SMD -0.10, 95% CI -0.25-0.05; p=0.21) or HRQoL (SMD 0.01, 95% CI -0.15-0.17; p=0.87). Home-PR is as effective as centre-PR in improving functional exercise capacity and quality of life compared to usual care, and is an option to enable access to pulmonary rehabilitation.

Antihypertensive treatment effect on exercise blood pressure and exercise capacity in older adults.

An exaggerated blood pressure (BP) response to exercise and low exercise capacity are risk factors for cardiovascular disease (CVD). The effect of pharmacological antihypertensive treatment on exercise BP in older adults is largely unknown. This study investigates these effects accounting for differences in exercise capacity. Participants enrolled in the Southall and Brent Revisited (SABRE) study undertook a 6-min stepper test with expired gas analysis and BP measured throughout exercise. Participants were stratified by antihypertensive treatment status and resting BP control. Exercise systolic and diastolic BP (exSBP and exDBP) were compared between groups using potential outcome means [95% confidence intervals (CIs)] adjusted for exercise capacity. Exercise capacity was also compared by group. In total, 659 participants were included (mean age ± SD: 73 ± 6.6 years, 57% male). 31% of normotensive and 23% of hypertensive older adults with controlled resting BP had an exaggerated exercise BP. ExSBP was similar between normotensive and treated/controlled individuals [mean (95%CI): 180 (176 184) mmHg vs. 177 (173 181) mmHg, respectively] but was higher in treated/uncontrolled and untreated/uncontrolled individuals [mean (95% CI): 194 (190 197) mmHg, P < 0.001 and 199 (194 204) mmHg, P < 0.001, respectively]; these differences persisted after adjustment for exercise capacity and other confounders. Exercise capacity was lower in treated vs. normotensive individuals [mean (95% CI) normotensive: 16.7 (16.0,17.4) ml/kg/min]; treated/controlled: 15.5 (14.8,16.1) ml/kg/min, P = 0.009; treated/uncontrolled: [15.1 (14.5,15.7) ml/kg per min, P = 0.001] but was not reduced in untreated/uncontrolled individuals [mean (95% CI): 17.0 (16.1,17.8) ml/kg per min, P = 0.621]. Irrespective of resting BP control and despite performing less exercise, antihypertensive treatment does not fully mitigate an exaggerated BP response to exercise suggesting residual CVD risk in older adults.

Exercise versus airway clearance techniques for people with cystic fibrosis.

Exercise versus airway clearance techniques for people with cystic fibrosis.

Assessment of fusion pacing on exercise capacity in patients with cardiac resynchronisation therapy devices

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): British Heart Foundation Local Departmental Research Funding Background Cardiac resynchronisation therapy (CRT) using fusion pacing requires correct timing of left ventricular pacing to right ventricular activation. The SyncAV™ algorithm, achieves this by dynamic reassessment of intrinsic atrio-ventricular (AV) conduction to adjust the paced/sensed AV delay. However, it is unclear whether AV optimisation maintains resynchronisation during exercise, or whether loss of fusion could lead to decreased exercise capacity. Cardio-pulmonary exercise testing (CPET) is the gold standard method for assessing exercise performance and can provide prognostic information in the heart failure population. Purpose We therefore used CPET measures of exercise capacity to compare the SyncAV™ algorithm to conventional pacing with fixed AV delays, in a double blinded, randomised crossover study (NCT03768804). Methods Patients at least 6 months post-CRT implant performed 2 CPET tests at least 1 week apart, with randomisation to either SyncAV™ with fusion pacing or conventional biventricular pacing with a fixed AVD of 120ms. All other programming was optimised to produce the narrowest QRS duration possible at rest in each case. Results Twenty patients (11 male, age 71 [65-77] years, median [interquartile range]) were recruited, with both ischaemic and non-ischaemic aetiology of heart failure. All had clinical and/or echocardiographic response to CRT. Optimised Fixed AVD and SyncAV™programming resulted in similar narrowing of QRS duration (QRSd) from intrinsic rhythm at rest (131 [103-137] vs 134 [110-137] ms for fixed AVD and SyncAV™ groups respectively, p=0.85). Overall, there was no difference in peak oxygen consumption (V̇O2peak) between programming (14.91 [12.61-18.16] vs 15.61 [12.18-19.70] ml/kg/min, p=0.19), or oxygen consumption at anaerobic threshold (VT1) (7.36 [6.93-8.94] vs 7.87 [6.77-9.24] ml/kg/min, p=0.42), or in the time to reach either V̇O2PEAK (p=0.81) or VT1 (p=0.39). The BORG rating of perceived effort was also similar between groups. CPET performance was also analysed comparing whichever programming gave the narrowest QRSd at rest (119 [96-136] vs 134 [119-142] ms, p&amp;lt;0.01). Eight were narrower with fixed AVD, 8 with SyncAV™ and in 4 there was no difference. QRSd during exercise (p=0.03), peak O2 pulse (ml/beat, a surrogate of stroke volume, p=0.03) and cardiac efficiency (watts/ml/kg/min, p=0.04) were significantly improved when programmed to the narrowest QRS duration at rest. Conclusion There is no significant difference in exercise capacity or QRSd between the use of optimised fixed AVD or SyncAV™, lending reassurance to fusion pacing being adequately maintained on exercise. In addition, programming with whichever algorithm gives the narrowest QRSd at rest is associated with a narrower QRSd during exercise, higher peak stroke volume and improved cardiac efficiency. This supports the use of SyncAV™ in the 40% of patients where this gave the narrowest QRSd at rest.

Deriving personalised physical activity intensity thresholds by merging accelerometry with field-based walking tests: Implications for pulmonary rehabilitation.

During pulmonary rehabilitation (PR), patients receive individually tailored walking exercise training. The personalised nature of exercise prescription is a fundamental component of PR. Despite this, the measurement of physical activity (PA) has been limited to a ‘one size fits all’ approach and can be challenging to translate into clinically meaningful or real-world units, such as cadence. This discrepancy may partly explain the inconsistent evidence for the impact of PR on PA. It may also provide an opportunity to standardise PA assessment in the context of chronic respiratory disease (CRD) and PR, where field-based walking tests are routine measures. This technical note provides an example of how to develop personalised PA intensity thresholds, calibrated against an individual’s performance on the Incremental Shuttle Walking Test (ISWT; maximal) and Endurance Shuttle Walk Test (ESWT; sub-maximal). These are externally paced tests, with each level (speed) of the tests denoting a specific speed (intensity); ranging 1.8 km/h (ISWT Level 1) to 8.5 km/h (ISWT Level 12). From the ESWT, it becomes possible to evaluate adherence to each individual’s walking exercise prescription. Future research should explore this approach and its responsiveness to PR. It may be possible to extend this methodology with the inclusion of physiological parameters (e.g., heart rate, calorimetry, and oxygen consumption) to derive relative intensity markers (e.g. moderate-to-vigorous), accounting for individual differences in exercise capacity, under the same paradigm as PR exercise prescription.

Differential Evaluating Effect on Exercise Capacity of Cardiopulmonary Exercise Testing and Treadmill Exercise Testing in Post-percutaneous Coronary Intervention Patients

Background: Treadmill exercise testing (TET) is commonly used to measure exercise capacity. Studies have shown that cardiopulmonary exercise testing (CPET) is more accurate than TET and is, therefore, regarded as the “gold standard” for testing maximum exercise capacity and prescribing exercise plans. To date, no studies have reported the differences in exercise capacity after percutaneous coronary intervention (PCI) using the two methods or how to more accurately measure exercise capacity based on the results of TET.Aims: This study aims to measure maximum exercise capacity in post-PCI patients and to recommend exercise intensities that ensure safe levels of exercise.Methods: We enrolled 41 post-PCI patients who were admitted to the Cardiac Rehabilitation Clinic at the First Medical Center, the Chinese PLA General Hospital, from July 2015 to June 2016. They completed CPET and TET. The paired sample t-test was used to compare differences in measured exercise capacity, and multiple linear regression was applied to analyze the factors that affected the difference.Results: The mean maximum exercise capacity measured by TET was 8.89 ± 1.53 metabolic equivalents (METs), and that measured by CPET was 5.19 ± 1.23 METs. The difference between them was statistically significant (p = 0.000) according to the paired sample t-test. The difference averaged 40.15% ± 2.61% of the exercise capacity measured by TET multiple linear regression analysis showed that the difference negatively correlated with waist-hip ratio (WHR).Conclusion: For the purpose of formulating more accurate exercise prescription, the results of TET should be appropriately adjusted when applied to exercise capacity assessment.Clinical Trial Registration:http://www.chictr.org.cn/ number, ChiCTR2000031543.

Analysis of exercise capacity, quality of life and leisure sports in patients with a Fontan circulation

Abstract Funding Acknowledgements Type of funding sources: None. Background/Introduction: Despite the improvement in survival, patients with a Fontan circulation are exposed to numerous complications as well as a reduced exercise capacity and quality of life. Purpose To assess the influence of the type of single ventricle (right vs. left) and the amount of sporting activity on exercise capacity and health related quality of life (HRQol) in a large group of Fontan patients. Methods Retrospective analysis of standardised cardiopulmonary exercise tests (CPET) performed on a treadmill between 2014 and 2019. Questionnaires to measure HRQol and sporting activity were sent to study participants. Results 79 patients were enrolled in this study (female, n = 31). 56 of them had a systemic right ventricle (SRV), 20 had a systemic left ventricle (SLV) and 3 had diverse anatomies. Median age at CPET was 12.2 years (range 6.2-34.4 years). The results for important exercise parameters were as follows: peak oxygen uptake (VO2max) 30.7 ± 6.2 ml/kg/min, oxygen uptake at anaerobic threshold (VO2-VAT) 24.7 ± 5.8 ml/kg/min, peak oxygen pulse 8.2 ± 3.4 mlO2/beat and VE/VCO2 slope 39.8 ± 9.1. There was no significant difference in VO2max, VO2-VAT, peak oxygen pulse and VE/CO2 slope between SRV and SLV patients: VO2max 30.2 ± 5.6 vs. 32.8 ± 7.5 ml/kg/min, p = 0.14; VO2-AT 24.4 ± 5.3 vs.25.7 ± 7.3 ml/kg/min, p = 0.53; peak oxygen pulse 7.8 ± 3.2 vs. 9.5 ± 3.9 mlO2/beat, p = 0.06; VE/CO2 slope 41.1 ± 9.6 vs. 36.9 ± 6.8, p = 0.10. Analyses of the questionnaires revealed that most of the patients do leisure sports (n = 60, 76%) with nearly half of them more than two hours per week (n = 26, 33%). In a subgroup analysis of patients under 18 years (n = 51, 65%) we found that nearly all of them participate in school sports (n = 50) and have a good subjective healthiness (n = 47). VO2-VAT and VO2max correlated positively with subjective healthiness (VO2-VAT r = 0.32, p &amp;lt; 0.05; VO2max r = 0.35, p &amp;lt; 0.05) as well as with the amount of leisure sports activity (hours/week) (VO2-VAT r = 0.37, p &amp;lt; 0.01; VO2max r = 0.50, p &amp;lt; 0.01). Conclusions By analysing a large group of patients in Fontan circulation we could demonstrate that there is no difference in exercise capacity between SRV and SLV patients. Furthermore, most of the patients participate in leisure sports and have a good subjective healthiness. In a subgroup of paediatric patients, we were able to show that a better exercise capacity is associated with increased leisure sports activity and a better subjective healthiness.

Exercise capacity improvement after cardiac rehabilitation following myocardial infarction and its association with long-term cardiovascular events.

Cardiovascular rehabilitation (CR) improves aerobic capacity and quality of life in patients after myocardial infarction (MI). The aim was to examine the associations between exercise capacity improvement and different clinically relevant cardiovascular events. This was a registry-based study of post-MI patients, referred to CR. All patients were submitted to exercise testing before and after CR (36 sessions, 2-3 times/week, and combined exercise). Patients were divided into two groups, based on the difference in exercise capacity before and after the CR programme with the cut-off of two metabolic equivalents (METs) improvement. We assessed the correlation between the extent of exercise capacity improvement and the following cardiovascular events: major adverse cardiac events (MACE), cardiovascular-related hospitalizations, and unplanned coronary angiography. A total of 499 patients were included (mean age 56 ± 10 years, 20% women). Both groups significantly improved in terms of exercise capacity, natriuretic peptide levels, resting heart rate, and resting diastolic pressure; however, lipid status significantly improved only in patients with ≥2 METs difference in exercise capacity. A total of 13.4% patients suffered MACE (median follow-up 858 days); 21.8% were hospitalized for cardiovascular reasons (median follow-up 791 days); and 19.8% had at least one unplanned coronary angiography (median follow-up 791 days). Exercise capacity improvement of ≥2 METs was associated with lower rates of MACE, cardiovascular hospitalizations, and unplanned coronary angiography in all examined univariate and multivariate models. This study has shown that exercise improvement of ≥2 METs is associated with a significant decrease in MACE, cardiac hospitalizations, and unplanned coronary angiography.

Critical care outcomes in patients with pre-existing pulmonary hypertension: insights from the ASPIRE registry.

Pulmonary hypertension (PH) is a life-shortening condition characterised by episodes of decompensation precipitated by factors such as disease progression, arrhythmias and sepsis. Surgery and pregnancy also place additional strain on the right ventricle. Data on critical care management in patients with pre-existing PH are scarce.We conducted a retrospective observational study of a large cohort of patients admitted to the critical care unit of a national referral centre between 2000–2017 to establish acute mortality, evaluate predictors of in-hospital mortality and establish longer term outcomes in survivors to hospital discharge.242 critical care admissions involving 206 patients were identified. Hospital survival was 59.3%, 94% and 92% for patients admitted for medical, surgical or obstetric reasons, respectively. Medical patients had more severe physiological and laboratory perturbations than patients admitted following surgical or obstetric interventions. Higher APACHE II (Acute Physiology and Chronic Health Evaluation) score, age and lactate, and lower oxygen saturation measure by pulse oximetry/inspiratory oxygen fraction (SpO2/FiO2) ratio, platelet count and sodium level were identified as independent predictors of hospital mortality. An exploratory risk score, OPALS (oxygen (SpO2/FiO2) ≤185; platelets ≤196×109·L−1; age ≥37.5 years; lactate ≥2.45 mmol·L−1; sodium ≤130.5 mmol·L−1), identified medical patients at increasing risk of hospital mortality. One (11%) out of nine patients who were invasively ventilated for medical decompensation and 50% of patients receiving renal replacement therapy left hospital alive. There was no significant difference in exercise capacity or functional class between follow-up and pre-admission in patients who survived to discharge.These data have clinical utility in guiding critical care management of patients with known PH. The exploratory OPALS score requires validation.