Cardiopulmonary exercise testing - refining the clinical perspective by combining assessments

The ventilatory efficiency parameters outperform peak oxygen consumption in monitoring the therapy effects in patients with hypertrophic cardiomyopathy

AIM

We sought the cardiopulmonary exercise testing (CPET) parameter that most accurately reflected therapeutic efficacy in patients with hypertrophic cardiomyopathy (HCM).

METHODS

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 (VO2); 2) VO2 at anaerobic threshold (AT); 3) oxygen pulse; 4) minute ventilation (VE)/carbon-dioxide (CO2) production slope; 5) VE/VCO2 at AT (VE/VCO2_AT); 6) VE/VCO2 nadir; 7) VE/VCO2 intercept; and 8) partial end-tidal pressure of carbon-dioxide (PETCO2) change during CPET.

RESULTS

Of 115 screened patients, 61 (52 ± 14 years, 43 % women) were included. Within subject therapy effects were detected only by the VE/VCO2 intercept and PETCO2 change, whereas the differences between medical regimens were detected by differences in VE/VCO2 nadir and VE/VCO2_AT changes after the treatment. The best predictors of the change in well-being were left ventricular outflow tract maximal gradient and VE/VCO2 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/VCO2 nadir.

CONCLUSION

Ventilatory efficiency parameters outperform peak VO2 in gauging therapy effects in patients with HCM.

A multi-method exploration of a cardiac rehabilitation service delivered by registered Clinical Exercise Physiologists in the UK: key learnings for current and new services

BACKGROUND

Cardiac rehabilitation has been identified as having the most homogenous clinical exercise service structure in the United Kingdom (UK), but inconsistencies are evident in staff roles and qualifications within and across services. The recognition of Clinical Exercise Physiologists (CEPs) as a registered health professional in 2021 in the UK, provides a potential solution to standardise the cardiac rehabilitation workforce. This case study examined, in a purposefully selected cardiac exercise service that employed registered CEPs, (i) how staff knowledge, skills and competencies contribute to the provision of the service, (ii) how these components assist in creating effective service teams, and (iii) the existing challenges from staff and patient perspectives.

METHODS

A multi-method qualitative approach (inc., semi-structured interviews, observations, field notes and researcher reflections) was employed with the researcher immersed for 12-weeks within the service. The Consolidated Framework for Implementation Research was used as an overarching guide for data collection. Data derived from registered CEPs (n = 5), clinical nurse specialists (n = 2), dietitians (n = 1), service managers/leads (n = 2) and patients (n = 7) were thematically analysed.

RESULTS

Registered CEPs delivered innovative exercise prescription based on their training, continued professional development (CPD), academic qualifications and involvement in research studies as part of the service. Exposure to a wide multidisciplinary team (MDT) allowed skill and competency transfer in areas such as clinical assessments. Developing an effective behaviour change strategy was challenging with delivery of lifestyle information more effective during less formal conversations compared to timetabled education sessions.

CONCLUSIONS

Registered CEPs have the specialist knowledge and skills to undertake and implement the latest evidence-based exercise prescription in a cardiac rehabilitation setting. An MDT service structure enables a more effective team upskilling through shared peer experiences, observations and collaborative working between healthcare professionals.

Evaluating current assessment techniques of cardiorespiratory fitness

INTRODUCTION

Considerable and convincing global data from cohorts across the health spectrum (i.e. apparently healthy to known disease) indicate that cardiorespiratory fitness (CRF) is a major predictor of overall and cardiovascular disease (CVD)-survival, seemingly with greater prognostic resolution compared to other traditional CVD risk factors. Therefore, the assessment of CRF in research and clinical settings is of major importance.

AREAS COVERED

In this manuscript, we review the technology of measuring CRF assessed by the 'gold standard,' cardiopulmonary exercise testing (CPET), as well as with various other methods (e.g. estimated metabolic equivalents, 6-minute walk tests, shuttle tests, and non-exercise equations that estimate CRF), all of which provide significant prognostic information for CVD- and all-cause survival. The literature through May 2024 has been cited.

EXPERT OPINION

The promotion of physical activity in efforts to improve levels of CRF is needed throughout the world to improve lifespan and, more importantly, healthspan. The routine assessment of CRF should be considered a vital sign that is routinely assessed in clinical practice.

Insights and recommendations into service model structure, staff roles and qualifications in a UK cancer specific clinical exercise service: a multi-method qualitative study

PURPOSE

Clinical exercise delivery in the United Kingdom is disparate in terms of service structure, staff roles and qualifications, therefore it is difficult to evaluate and compare across services. Our aim was to explore, in a purposely selected cancer exercise service that was recognised as effective; (i) how staff knowledge, skills and competencies contribute to the provision of the service, (ii) how these components assist in creating effective services, and (iii) to identify existing challenges from staff and service user perspectives.

METHODS

The Consolidated Framework for Implementation Research was used as an overarching guide to review the Prehab4Cancer service. Exercise specialists and service user perspectives were explored using a multi-method approach (online semi-structured interviews, online focus group and in-person observation) and data triangulation.

RESULTS

Exercise specialists were educated to a minimum of undergraduate degree level with extensive cancer-specific knowledge and skills, equivalent to that of a Registration Council for Exercise Physiologist (RCCP) Clinical Exercise Physiologist. Workplace experience was essential for exercise specialist development in behaviour change and communications skills.

CONCLUSIONS

Staff should be educated to a level comparable with the standards for registered RCCP Clinical Exercise Physiologists, which includes workplace experience to develop knowledge, skills and competencies in real-world settings.

Nurse facilitated 5000 m running at Parkrun improves vulnerable adolescent health in a high deprivation area: A matched pair randomized control trial

OBJECTIVE

To examine the effect of weekly nurse facilitated 5000 m running at Parkrun on markers of health in vulnerable adolescents from a high deprivation area.

DESIGN

A matched pair randomized control trial.

SAMPLE

Twenty-five adolescents aged 13-18, 90% identifying as Māori/Pasifika ethnicity.

INTERVENTION

The intervention (INT) group participated in 6-10 Parkruns within 10 weeks, and a control group (CON) participated in one Parkrun only. A nurse facilitated the intervention offering support and encouragement at each Parkrun.

MEASUREMENTS

Pre- and post-intervention testing sessions for cardiorespiratory fitness (CRF), glycated hemoglobin, body mass index (BMI), skeletal muscle mass (SMM), body fat, and hand grip strength (STR) were conducted.

RESULTS

Parkrun improved CRF (F = 5.308, p = 0.035) and 5000 m time (t = 2.850, p = 0.019) by 5.5 ± 4.9 min (11.2%). Parkrun conferred a large beneficial effect on CRF (η2 = 0.249) a moderate beneficial effect on glycated hemoglobin levels (η2 = 0.119), and small beneficial effects upon SMM (η2 = 0.037) and body fat (η2 = 0.017).

CONCLUSION

A weekly dose of nurse facilitated Parkrun can be recommended as a simple, accessible intervention that confers multiple beneficial effects on markers for health in adolescents from a high deprivation area.

Early reduction in cardiorespiratory fitness and diastolic reserve following radiation therapy for lung cancer

BACKGROUND

Contemporary radiotherapy for the treatment of lung cancer is effective in targeting tumor tissue while limiting heart exposure, yet cardiac toxicity still occurs, often becoming clinically apparent years later. Cardiorespiratory fitness (CRF) is an independent predictor of cardiovascular, cancer-related, and overall mortality and may serve as a sensitive measure of subclinical cardiac toxicity following anti-cancer treatments. Prior work has demonstrated a significant relationship between reduced CRF and impaired left-ventricular (LV) diastolic reserve in cancer survivors following thoracic radiotherapy. The purpose of this study was to assess early longitudinal changes in CRF and cardiac function in patients with lung cancer following radiotherapy.

METHODS

Ten patients (69 [61-76] years, 70% female) with lung cancer without known cardiovascular disease scheduled to receive radiotherapy involving a clinically-relevant heart dose (≥ 5 Gy to > 10% of heart volume) were evaluated prior to and following treatment. Changes in CRF (peak oxygen consumption [VO2peak], oxygen uptake efficiency slope [OUES]), cardiac function (LV ejection fraction [LVEF], rest and exercise diastolic function [diastolic functional reserve index (DFRI)]), cardiac biomarkers (N-terminal pro-brain natriuretic peptide [NT-proBNP], high-sensitivity C-reactive protein [hsCRP]), and health-related quality of life (HRQOL; Functional Assessment of Cancer Therapy-General-7 [FACT-G7]) were measured.

RESULTS

The VO2peak was reduced at baseline (1.245 [0.882-1.605] L·min- 1; 70 [62-86] %-predicted) and significantly declined (1.095 [0.810-1.448] L·min- 1, P = 0.047; 62 [56-76] %-predicted, P = 0.005) at 6.0 [3.0-6.0] months post-radiotherapy. Similarly, a significant decline in the OUES was observed (1.63 [1.27-1.88] to 1.57 [1.12-1.75], P = 0.032). Systolic cardiac function was normal at baseline and did not change following radiotherapy (LVEF; 62 [56-65]% to 66 [57-68]%, P = 0.475). The DFRI significantly declined following radiotherapy (34.9 [22.7-41.6] vs. 12.8 [3.1-35.9]). The hsCRP increased significantly from 4.4 [1.4-5.8] to 6.1 [3.7-20.7] g/L, P = 0.047 with a trend towards higher levels of NT-proBNP (65 [49-125] to 121 [88-191] pg/mL, P = 0.110). Health-related quality of life significantly decreased (FACT-G7; 21.5 [18.8-25] to 15.5 [11.5-20]; P = 0.021) post-radiotherapy.

CONCLUSIONS

Patients with lung cancer receiving radiotherapy with a clinically-significant heart dose experience reductions in CRF (VO2peak, OUES) as early as six months following treatment with concurrent reductions in diastolic reserve (DFRI), HRQOL, and increases in cardiac biomarkers (NT-proBNP, hsCRP).

Evaluation of cardiovascular risk factors in children aged 6-16 years and their evolution in early adulthood in a 10-year follow-up study

OBJECTIVE

Obesity and arterial hypertension (AH) in children represent well-recognized risk factors for cardiovascular (CV) events during adult life. We investigated any changes regarding several CV risk (CVR) factors in children after a 10-year follow-up period.

METHODS

A cohort of 143 healthy children, elementary/high school students, 6-16 years old, was initially evaluated in 2010-2011 regarding CVR factors [obesity, blood pressure (BP), aortic stiffness (PWV), lipid profile] plus food habits/sports activity. At 10-years follow-up (2020-2021), 63/143 (44%) young adults were re-evaluated.

RESULTS

Children with obesity (45%) had increased BP (p < 0.001) and a less favorable LDL-C/triglycerides profile (p = 0.001) compared to overweight/normoweight ones. In a 10-year follow-up, obesity and exercise improved (p < 0.001 and p = 0.005), systolic BP (SBP) (102 ± 13 vs. 118 ± 11 mmHg, p < 0.001) and PWV increased (6.1 ± 1 vs. 7.7 ± 1.1 m/sec, p < 0.001), LDL-C (96 ± 21 vs. 86 ± 24 mg/dl, p = 0.004) and HDL-C + (64 ± 18 vs. 55 ± 10 mg/dl, p < 0.001) decreased, triglycerides increased (62 ± 21 vs. 73 ± 34 mg/dl, p = 0.04), and food approached the western model of nutrition (less fish/fruits). In children/young adults, BMI was associated with age (Beta = 0.47, p < 0.001 and Beta = 0.36, p = 0.004), SBP (Beta = 0.46 and Beta = 0.52, p < 0.001), and LDL-C (Beta = 0.27 and Beta = 0.44, p < 0.001).

CONCLUSIONS

In children with obesity, increased BMI and waist circumference were related to SBP and a less favorable lipid profile. At the 10-year re-evaluation, obesity was partially improved, physical activity was increased, and SBP had reached the high-normal levels in a substantial number of young adults, while lipid profile was less favorable (for HDL-C/triglycerides) compared to baseline evaluation. Our results highlight the evolution of CVR factors from childhood to early adulthood.

Blood and Salivary Cortisol Variations in Athletes in Relation to Cardiopulmonary Exercise Testing

Background and Objectives: Cortisol is a valuable marker for assessing the body's response to any form of stress. We conducted this study in order to evaluate the variations of salivary and serum cortisol levels in professional football players in relation to cardiopulmonary exercise testing (CPET) and their significance in potentially evaluating overtraining in athletes. Also, the question of whether salivary cortisol determination could fully substitute serum sampling was addressed. Materials and Methods: A total of 19 male professional football players were evaluated by measuring serum cortisol levels at rest (T0) and immediately after a CPET (T1) and salivary cortisol levels at rest (T0), 10 min after a CPET (T2), and 30 min after a CPET (T3). Results: T0 serum cortisol showed a statistically significant correlation with the oxygen uptake at the anaerobic threshold divided by the body weight (VO2-AT/weight), as did the T2 salivary cortisol with the maximum oxygen uptake at the anaerobic threshold (VO2-AT) and VO2-AT/weight. T0 salivary cortisol was significantly correlated with the subjects' height and the predicted O2 pulse. Conclusions: While some correlations were discovered, they are insufficient to recommend cortisol as a routine biomarker in athletes' evaluation. However, significant correlations were established between salivary and serum determinations, meaning that the non-invasive procedure could substitute venous blood sampling.

Contribution of hemoglobin concentration to cardiorespiratory fitness in black African American patients with recently decompensated heart failure and reduced ejection fraction

BACKGROUND

Previous studies have shown that patients with heart failure with reduced ejection fraction (HFrEF) and anemia have reduced peak oxygen consumption (VO2). Black or African American (B-AA) patients have a higher prevalence of anemia and are underrepresented in clinical studies of HFrEF. The aim of this study was to determine the contribution of hemoglobin to peak VO2 in B-AA patients recently hospitalized for acute decompensated HFrEF.

METHODS

We analyzed cardiopulmonary exercise testing (CPX) data measured within two weeks of discharge for acute decompensated HF in B-AA patients with HFrEF (left ventricular ejection fraction [LVEF] ≤40%) without severe anemia (Hb<8 g/dL). Blood samples were collected prior to CPX. Data are reported as median [interquartile range] and compared between groups with the Mann-Whitney, Chi-Square, and Spearman's rank tests.

RESULTS

We included 81 patients; 27 (33%) women, 57 [27-79] years of age, Body Mass Index of 33 [15-55] kg/m2 and LVEF of 30 [23-36] %. Hemoglobin ranged between 9.1 to 18.1 g/dL (median= 13.3 [11.9-14.5] g/dL); 26 (32%) were considered to have anemia based on a Hb concentration of males <13 g/dL and females <12 g/dL. Peak VO2 was lower in patients with anemia (11.8 [10.0-14.2] vs. 14.1 [10.6-17.0] mL·kg-1·min-1; P=0.010) with a significant correlation between peak VO2 and hemoglobin concentration (R=+0.455; P<0.001).

CONCLUSIONS

Anemia is prevalent among B-AA patients with recently decompensated HFrEF and appears to be a significant contributor to reductions in peak VO2.

Simultaneous exercise stress cardiac magnetic resonance and cardiopulmonary exercise testing to elucidate the Fick components of aerobic exercise capacity: a feasibility and reproducibility study and pilot study in hematologic cancer survivors

BACKGROUND

Patients treated for hematologic malignancy often experience reduced exercise capacity and increased fatigue; however whether this reduction is related to cardiac dysfunction or impairment of skeletal muscle oxygen extraction during activity is unknown. Cardiopulmonary exercise testing (CPET) coupled with stress cardiac magnetic resonance (ExeCMR), may provide a noninvasive method to identify the abnormalities of cardiac function or skeletal muscle oxygen extraction. This study was performed to determine the feasibility and reproducibility of a ExeCMR + CPET technique to measure the Fick components of peak oxygen consumption (VO2) and pilot its discriminatory potential in hematologic cancer patients experiencing fatigue.

METHODS

We studied 16 individuals undergoing ExeCMR to determine exercise cardiac reserve with simultaneous measures of VO2. The arteriovenous oxygen content difference (a-vO2diff) was calculated as the quotient of VO2/cardiac index (CI). Repeatability in measurements of peak VO2, CI, and a-vO2diff was assessed in seven healthy controls. Finally, we measured the Fick determinants of peak VO2 in hematologic cancer survivors with fatigue (n = 6) and compared them to age/gender-matched healthy controls (n = 6).

RESULTS

Study procedures were successfully completed without any adverse events in all subjects (N = 16, 100%). The protocol demonstrated good-excellent test-retest reproducibility for peak VO2 (intraclass correlation coefficient [ICC] = 0.992 [95%CI:0.955-0.999]; P < 0.001), peak CI (ICC = 0.970 [95%CI:0.838-0.995]; P < 0.001), and a-vO2diff (ICC = 0.953 [95%CI:0.744-0.992]; P < 0.001). Hematologic cancer survivors with fatigue demonstrated a significantly lower peak VO2 (17.1 [13.5-23.5] vs. 26.0 [19.7-29.5] mL·kg-1·min-1, P = 0.026) and lower peak CI (5.0 [4.7-6.3] vs. 7.4 [7.0-8.8] L·min-1/m2, P = 0.004) without a significant difference in a-vO2diff (14.4 [11.8-16.9] vs. 13.6 [10.9-15.4] mLO2/dL, P = 0.589).

CONCLUSIONS

Noninvasive measurement of peak VO2 Fick determinants is feasible and reliable with an ExeCMR + CPET protocol in those treated for a hematologic malignancy and may offer insight into the mechanisms of exercise intolerance in those experiencing fatigue.

Patient Perceptions of Exertion and Dyspnea With Interleukin-1 Blockade in Patients With Recently Decompensated Systolic Heart Failure

Interleukin-1 (IL-1) blockade is an anti-inflammatory treatment that may affect exercise capacity in heart failure (HF). We evaluated patient-reported perceptions of exertion and dyspnea at submaximal exercise during cardiopulmonary exercise testing (CPET) in a double-blind, placebo-controlled, randomized clinical trial of IL-1 blockade in patients with systolic HF (REDHART [Recently Decompensated Heart Failure Anakinra Response Trial]). Patients underwent maximal CPET at baseline, 2, 4, and 12 weeks and rated their perceived level of exertion (RPE, on a scale from 6 to 20) and dyspnea on exertion (DOE, on a scale from 0 to 10) every 3 minutes throughout exercise. Patients also answered 2 questionnaires to assess HF-related quality of life: the Duke Activity Status Index and the Minnesota Living with Heart Failure Questionnaire. From baseline to the 12-week follow-up, IL-1 blockade significantly reduced RPE and DOE at 3- and 6-minutes during CPET without changing values for heart rate, oxygen consumption, and cardiac workload at 3- and 6-minutes. Linear regression identified 6-minute RPE to be a strong independent predictor of both physical symptoms (Minnesota Living with Heart Failure Questionnaire; β = 0.474, p = 0.002) and perceived exercise capacity (Duke Activity Status Index; β = -0.443, p = 0.008). In conclusion, patient perceptions of exertion and dyspnea at submaximal exercise may be valuable surrogates for quality of life and markers of response to IL-1 blockade in patients with HF.

Rationale and design of interleukin-1 blockade in recently decompensated heart failure (REDHART2): a randomized, double blind, placebo controlled, single center, phase 2 study

Background

Heart failure (HF) is a global leading cause of mortality despite implementation of guideline directed therapy which warrants a need for novel treatment strategies. Proof-of-concept clinical trials of anakinra, a recombinant human Interleukin-1 (IL-1) receptor antagonist, have shown promising results in patients with HF.

Method

We designed a single center, randomized, placebo controlled, double-blind phase II randomized clinical trial. One hundred and two adult patients hospitalized within 2 weeks of discharge due to acute decompensated HF with reduced ejection fraction (HFrEF) and systemic inflammation (high sensitivity of C-reactive protein > 2 mg/L) will be randomized in 2:1 ratio to receive anakinra or placebo for 24 weeks. The primary objective is to determine the effect of anakinra on peak oxygen consumption (VO₂) measured at cardiopulmonary exercise testing (CPX) after 24 weeks of treatment, with placebo-corrected changes in peak VO₂ at CPX after 24 weeks (or longest available follow up). Secondary exploratory endpoints will assess the effects of anakinra on additional CPX parameters, structural and functional echocardiographic data, noninvasive hemodynamic, quality of life questionnaires, biomarkers, and HF outcomes.

Discussion

The current trial will assess the effects of IL-1 blockade with anakinra for 24 weeks on cardiorespiratory fitness in patients with recent hospitalization due to acute decompensated HFrEF.

Trial registration: The trial was registered prospectively with ClinicalTrials.gov on Jan 8, 2019, identifier NCT03797001.

Cardiopulmonary Exercise Testing and Cardiac Biomarker Measurements in Young Football Players: A Pilot Study

Constant and intense physical activity causes physiological adaptive changes in the human body, but it can also become a trigger for adverse events, such as sudden cardiac arrest or sudden cardiac death. Our main objective was to assess the use of combined cardiopulmonary exercise testing (CPET) and cardiac biomarker determinants in young professional athletes. We conducted a study which involved the full examination of 19 football players, all male, aged between 18 and 20 years old. They underwent standard clinical and paraclinical evaluation, a 12-lead electrocardiogram (ECG), and transthoracic echocardiography (TTE). Afterwards, a tailored CPET was performed and peripheral venous blood samples were taken before and 3 h after the test in order to determine five biomarker levels at rest and post-effort. The measured biomarkers were cardiac troponin I (cTnI), myoglobin (Myo), the MB isoenzyme of creatine-kinase (CK-MB), the N-terminal prohormone of brain natriuretic peptide (NT-proBNP) and D-dimers. While cTnI and NT-proBNP levels were undetectable both at rest and post-effort in all subjects, the variations in Myo, CK-MB and D-dimers showed significant correlations with CPET parameters. This highlights the potential use of combined CPET and biomarker determinants to evaluate professional athletes, and encourages further research on larger study groups.

Heart Failure After ST-Elevation Myocardial Infarction: Beyond Left Ventricular Adverse Remodeling

ST-segment elevation myocardial infarction (STEMI) remains a significant source of morbidity and mortality worldwide. Despite advances in treatment leading to a significant reduction in the early complications and in-hospital mortality, a significant proportion of STEMI survivors develop heart failure (HF) at follow-up. The classic paradigm of HF after STEMI is one characterized by left ventricular adverse remodeling (LVAR) and encompasses the process of regional and global structural and functional changes that occur in the heart as a consequence of loss of viable myocardium, increased wall stress and neurohormonal activation, and results in HF with reduced ejection fraction (HFrEF). More recently, however, with further improvements in the treatment of STEMI the incidence and entity of LVAR appear to be largely reduced, yet the risk for HF following STEMI is not abolished and remains substantial, identifying a new paradigm by which patients with STEMI present with HF and preserved EF (HFpEF) characterized by reduction of diastolic or systolic reserve independent of LVAR.

Comparison of Cardiorespiratory Fitness in Black or African American Versus Caucasian Patients With Heart Failure

PURPOSE

Cardiopulmonary exercise testing (CPX) is a well-established assessment with important insight into prognosis and therapeutic efficacy in patients with heart failure (HF). Prior studies have identified several clinical differences between Black or African American (B-AA) and Caucasian patients with HF. Differences in key CPX responses between these two groups require further investigation.

METHODS

Using a database consisting of subjects with symptomatic HF who had undergone CPX for inclusion in various prospective randomized clinical trials, we identified 198 (n = 94 [47%] B-AA; n = 105 [53%] Caucasian) patients with a qualifying baseline CPX. Significant univariate predictors of peak oxygen uptake (V˙o2peak) were included in a multivariate linear regression model.

RESULTS

When compared with Caucasian patients, B-AA were younger (mean ± SD = 54.8 ± 10.0 vs 57.9 ± 9.6 yr, P = .03), had higher C-reactive protein (CRP) (median [IQR] = 4.9 [2.3, 8.8] vs 1.9 [0.6, 5.5] mg/L, P < .0001), lower hemoglobin (13.0 ± 1.8 vs 13.8 ± 1.6 g/dL, P = .003), and lower left ventricular ejection fraction (LVEF) (40 [32, 51] vs 53 [43, 59]%, P < .00010). During CPX, B-AA patients also had lower V˙o2peak (14.6 ± 3.9 vs 17.6 ± 4.8 mL·kg-1·min-1, P < .0001). No differences were observed between B-AA and Caucasian in the minute ventilation/carbon dioxide production (V˙e/V˙co2) slope (P = .14). The difference in V˙o2peak between B-AA and Caucasian was largely attenuated after adjusting for age, body mass index, CRP, N-terminal pro-brain natriuretic peptide, hemoglobin, LVEF, and peak HR (14.1: 95% CI, 13.2-14.9 vs 15.6: 95% CI, 14.4-16.8 mL·kg-1·min-1, P = .053).

CONCLUSIONS

Directly measured V˙o2peak was significantly lower in B-AA than in Caucasians with HF. This is largely explained by differences in clinical characteristics, whereas no significant differences were observed in the V˙e/V˙co2 slope.

Assessment of Cardiorespiratory and Metabolic Responses in Women with Obesity After Surgically Induced Weight Loss: Results from a Pilot Study

PURPOSE

Bariatric surgery is effective in controlling severe obesity. However, studies investigating the impact of surgically induced weight loss on cardiorespiratory and metabolic responses during maximal effort are controversial. The aim of this study was to assess cardiorespiratory and metabolic responses in women with obesity after bariatric surgery.

MATERIALS AND METHODS

We performed a secondary analysis on data from a pilot study with women with obesity submitted to bariatric surgery and who did not participate in a controlled physical training program. Anthropometry, pulmonary function (spirometry), and cardiorespiratory fitness (cardiopulmonary exercise testing [CPX]) were assessed before and after bariatric surgery.

RESULTS

Thirty-four women were included (38.7 ± 9.6 years, body mass index = 44.1 ± 6.3 kg/m²). Postoperative assessment was conducted 9.4 ± 2.7 months after surgery. After surgery, we observed a reduction in all anthropometric measurements (mean loss of 28.6 kg, p < 0.001), and improvement in spirometry values (p < 0.001). Relative VO_2peak (mL/kg/min) increased slightly (Δ = 1.7; p = 0.06); however, absolute VO_2peak (L/min) reduced significantly (Δ =  - 0.398; p < 0.001). We also observed an increase of 1.3 min (p < 0.001) in CPX duration, a reduction of 11.3 bpm (p < 0.001) in resting heart rate, and a decrease of systolic (p = 0.02) and diastolic (p < 0.001) blood pressures at peak effort.

CONCLUSION

Surgically induced weight loss without exercise training improved cardiac reserve, ventilatory response, blood pressure, and resting heart rate. Cardiorespiratory fitness reflected by relative VO_2peak increased slightly, despite increased tolerance to CPX.

Preservation of Cardiac Reserve and Cardiorespiratory Fitness in Patients With Acute De Novo Versus Acute on Chronic Heart Failure With Reduced Ejection Fraction

There is limited understanding on the potential differences in the pathophysiology between de novo heart failure with reduced ejection fraction (HFrEF) and acute on chronic HFrEF. The aim of this study was to assess differences in cardiorespiratory fitness (CRF) parameters between de novo heart failure and acute on chronic HFrEF using cardiopulmonary exercise testing (CPX). We retrospectively analyzed CPX data measured within 2 weeks of discharge following acute hospitalization for HFrEF. Data are reported as median and interquartile range or frequency and percentage (%). We included 102 patients: 32 (31%) women, 81 (79%) black, 57 (51 to 64) years of age, BMI of 34 (29 to 39) Kg/m². Of these, 26 (25%) had de novo HFrEF and 76 (75%) had acute on chronic HFrEF. When compared with acute on chronic, patients with de novo HFrEF had a significantly higher peak oxygen consumption (VO₂) (16.5 [12.2 to 19.4] vs 12.8 [10.1 to 15.3] ml·kg^-1·min^-1, p <0.001), %-predicted peak VO₂ (58% [51 to 75] vs 49% [42 to 59]) p = 0.012), peak heart rate (134 [117 to 147] vs 117 [104 to 136] beats/min, p = 0.004), peak oxygen pulse (12.2 [10.5 to 15.5] vs 9.9 [8.0 to 13.1] ml/beat, p = 0.022) and circulatory power (2,823 [1,973 to 3,299] vs 1,902 [1,372 to 2,512] mm Hg·ml·kg^-1·min^-1, p = 0.002). No significant difference in resting left ventricular ejection fraction was found between groups. In conclusion, patients with de novo HFrEF have better CRF parameters than those with acute on chronic HFrEF. These differences are not explained by resting left ventricular systolic function but may be related to greater preservation in cardiac reserve during exercise in de novo HFrEF patients.

Power Output and Efficiency During Supine, Recumbent, and Upright Cycle Ergometry

Recumbent and supine cycling are common exercise modes in rehabilitation and clinical settings but the influence of postures on work efficiency is unclear. Therefore, the aim of this study was to compare metabolic and ventilatory efficiency during upright, recumbent, and supine postures. Potential differences should be assessed for suitable diagnostics and for prescriptions of training that probably is performed in alternative postures. Eighteen healthy subjects (age: 47.2 ± 18.4 years; 10 female, 8 male) participated in the study and each completed three incremental cycle ergometer tests until exhaustion in upright, recumbent (40°), and supine positions. Gas exchange, heart rate (HR), and lactate concentrations were analyzed and efficiency was calculated subsequently. Testing sessions were performed in random order within a 2-week period. Upright cycling resulted in significantly higher peak values [power output, oxygen uptake (Vo₂), HR] as well as performance at lactate and ventilatory thresholds in comparison to recumbent or supine positions. Vco₂/Vo₂ slope and ventilatory efficiency (VE/Vco₂ slope) were not affected by posture. Aerobic work efficiency (Vo₂/P slope) and gross efficiency (GE) differed significantly between postures. Hereby, GE was lowest in supine cycling, particularly obvious in a mainly aerobic condition at 70 Watt [Median 11.6 (IQR 10.9-13.3) vs. recumbent: 15.9 (IQR 15.6-18.3) and upright: 17.4 (IQR 15.1-18.3)]. Peak power as well as GE and work efficiency values are influenced by cycling position, reinforcing the importance of adjusting test results for training prescriptions. Surprisingly, ventilatory efficiency was not affected in this study and therefore does not seem to falsify test results for pulmonary diagnostics.