Association Between 6-Minute Walk Test Distance and Objective Variables of Functional Capacity After Exercise Training in Elderly Heart Failure Patients With Preserved Ejection Fraction: A Randomized Exercise Trial

Accuracy of the 6-Minute Walk Test for Assessing Functional Capacity in Patients With Heart Failure With Preserved Ejection Fraction and Other Chronic Cardiac Pathologies: Results of the ExIC-FEp Trial and a Meta-Analysis

BACKGROUND

Heart diseases, particularly heart failure, significantly impact patient quality of life and mortality rates. Functional capacity assessment is vital for predicting prognosis and risk in these patients. While the cardiopulmonary exercise test is considered the gold standard, the 6-minute walk test has emerged as a more accessible alternative. However, the screening accuracy and optimal cut-off points of the 6-minute walk test for detecting severely reduced functional capacity in cardiac pathologies, including heart failure with preserved ejection fraction, are unclear. The study aimed to analyse the diagnostic accuracy of the 6-minute walk test for detecting reduced functional capacity, defined as VO2max < 14 ml/kg/min, compared with the cardiopulmonary exercise test in participants with heart failure with preserved ejection fraction using data from the "Ejercicio en Insuficiencia Cardiaca con Fracción de Eyección Preservada" (ExIC-FEp) trial; and to compare these results with previous studies investigating the screening accuracy for assessing functional capacity of the 6-minute walk test in participants with other chronic cardiac pathologies through a meta-analysis.

RESULTS

The ExIC-FEp trial involved 22 participants with heart failure with preserved ejection fraction, who were not treated with beta-blockers, using the cardiopulmonary exercise test, specifically VO2max, as the reference test. The 6-minute walk test had a sensitivity of 70%, a specificity of 80%, and an area under the curve of 76% in the ExIC-FEp trial. Five studies were included in the meta-analysis showing a sensitivity of 79%, a specificity of 78%, and an area under the curve of 85%.

CONCLUSION

In conclusion, the 6-minute walk test holds promise as a screening tool for assessing functional capacity in heart failure with preserved ejection fraction and chronic heart diseases, with a VO2max < 14 ml/kg/min as a reference point. It demonstrates moderate to good screening accuracy. However, the screening accuracy and optimal cut-off points of the 6-minute walk test for detecting severely reduced functional capacity, regardless of aetiology, are unclear.

TRIAL REGISTRATION

NCT05726474. Registered 16 February 2023, https://clinicaltrials.gov/study/NCT05726474 .

Effects of sacubitril/valsartan on the functional capacity of real-world patients in Italy: the REAL.IT study on heart failure with reduced ejection fraction

Background

Heart failure (HF) significantly affects the morbidity, mortality, and quality of life of patients. New therapeutic strategies aim to improve the functional capacity and quality of life of patients while controlling HF-related risks. Real-world data on both the functional and cardiopulmonary exercise capacities of patients with HF with reduced ejection fraction upon sacubitril/valsartan use are lacking.

Methods

A multicenter, retrospective, cohort study, called REAL.IT, was performed based on the data collected from the electronic medical records of nine specialized HF centers in Italy. Cardiopulmonary exercise testing was performed at baseline and after 12 months of sacubitril/valsartan therapy, monitoring carbon dioxide production (VCO2) and oxygen consumption (VO2).

Results

The functional capacities of 170 patients were evaluated. The most common comorbidities were hypertension and diabetes (i.e., 53.5 and 32.4%, respectively). At follow-up, both the VO2 peak (from 15.1 ± 3.7 ml/kg/min at baseline to 17.6 ± 4.7 ml/kg/min at follow-up, p < 0.0001) and the predicted % VO2 peak (from 55.5 ± 14.1 to 65.5 ± 16.9, p < 0.0001) significantly increased from baseline. The VO2 at the anaerobic threshold (AT-VO2) increased from 11.5 ± 2.6 to 12.5 ± 3.3 ml/kg/min (p = 0.021), and the rate ratio between the oxygen uptake and the change in work (ΔVO2/Δwork slope) improved from 9.1 ± 1.5 to 9.9 ± 1.6 ml/min/W (p < 0.0001).

Conclusions

Sacubitril/valsartan improves the cardiopulmonary capacity of patients with HFrEF in daily clinical practice in Italy.

Effects of Exercise Interventions on Aerobic Capacity in Patients With Heart Failure With Preserved Left Ventricular Ejection Fraction: Systematic Review and Network Meta-Analysis

Exercise is an important component of rehabilitation care for patients with heart failure with preserved ejection fraction (HFpEF). However, it is unclear which type of physical rehabilitation exercise is most effective. Thus, the aim of this study was to determine the relative effects of different types of exercise interventions on aerobic capacity measured by peak oxygen consumption (VO 2 peak; in mL/kg·min) in patients with HFpEF. We searched different electronic databases until December 2020 for randomized controlled trials that evaluated the effects of different types of exercise interventions on VO 2 peak of patients with HFpEF. Mean difference, standardized mean difference (SMD), and 95% confidence intervals (CIs) were calculated. Fixed and random-effects Bayesian network meta-analysis was used to compare the relative effectiveness of the different exercise interventions. Nineteen studies met the study criteria, including 720 patients. Comparing the physical rehabilitation interventions with usual care (control group), inspiratory muscle training was the highest ranked exercise intervention with an SMD of 3.6 mL/kg·min (95% CI, 2.3-4.8), followed by the group undergoing high-intensity interval training with a significant pooled improvement in VO 2 peak 3.5 (95% CI, 2.6-4.4) and combined aerobic and resistance exercise with an SMD of 3.2 (95% CI, 1.4-5.0). The inspiratory muscle training, high-intensity interval training, and combined aerobic and resistance exercise were the highest ranked physical rehabilitation intervention to improve VO 2 peak. These interventions should be considered as a component in the care of patients with HFpEF. Registration: https://www.crd.york.ac.uk/PROSPERO/ ; Unique identifier: CRD42021256442.

Comparative effect of different physical exercise training on exercise capacity and cardiac function in heart failure with preserved ejection fraction: a network meta-analysis-ExIC-FEp Study

AIMS

This network meta-analysis aimed to compare the effect of different types of physical exercise [endurance training, endurance/resistance training, and high-intensity interval training (HIIT)] on exercise capacity and cardiac function parameters in patients with heart failure with preserved ejection fraction.

METHODS AND RESULTS

A systematic search of the MEDLINE (via PubMed), Scopus, and Web of Science databases was conducted to identify experimental studies addressing the effect of different physical exercise training programmes on exercise capacity and cardiac function in heart failure with preserved ejection fraction. Comparative evaluation of the effect of exercise training type was performed by conducting a standard pairwise meta-analysis and a network meta-analysis for direct and indirect comparisons between exercise training types and controls/non-interventions. Eleven studies were included in the analysis showing that endurance training improves the main exercise capacity parameters (VO2peak, workload, exercise time, peak heart rate, VO2, and 6 min walk distance). Additionally, endurance/resistance training showed a significant effect on VO2peak, workload, early mitral annulus velocity, and early mitral/mitral annulus velocity ratio. Finally, HIIT showed a significant effect on VO2peak, VO2, and the early mitral/mitral annulus velocity ratio.

CONCLUSION

Our findings support the effect of three different types of physical exercise on exercise capacity, mainly VO2peak. Additionally, endurance/resistance training and HIIT could reverse left ventricular remodelling in patients with heart failure with preserved ejection fraction.

REGISTRATION

PROSPERO: CRD42021276111.

Comparative Effect of Two Types of Physical Exercise for the Improvement of Exercise Capacity, Diastolic Function, Endothelial Function and Arterial Stiffness in Participants with Heart Failure with Preserved Ejection Fraction (ExIC-FEp Study): Protocol for a Randomized Controlled Trial

(1) Background: Heart failure (HF) with preserved ejection fraction (HFpEF) accounts for approximately 50% of all patients with HF. In the absence of pharmacological treatments that have been successful in reducing mortality or morbidity in this pathology, physical exercise is recognized as an important adjunct in the treatment of HF. Therefore, the objective of this study is to compare the efficacy of combined training and high intensity interval training (HIIT) on exercise capacity, diastolic function, endothelial function, and arterial stiffness in participants with HFpEF. (2) Methods: The ExIC-FEp study will be a single-blind, 3-arm, randomized clinical trial (RCT) conducted at the Health and Social Research Center of the University of Castilla-La Mancha. Participants with HFpEF will be randomly assigned (1:1:1) to the combined exercise, HIIT or control group to evaluate the efficacy of physical exercise programs on exercise capacity, diastolic function, endothelial function, and arterial stiffness. All participants will be examined at baseline, at three months and at six months. (3) Results: The findings of this study will be published in a peer-reviewed journal. (4) Conclusions: This RCT will represent a significant advance in the available scientific evidence on the efficacy of physical exercise in the treatment of HFpEF.

Differential plasma protein expression after ingestion of essential amino acid-based dietary supplement verses whey protein in low physical functioning older adults

In a recent randomized, double-blind, placebo-controlled trial, we were able to demonstrate the superiority of a dietary supplement composed of essential amino acids (EAAs) over whey protein, in older adults with low physical function. In this paper, we describe the comparative plasma protein expression in the same subject groups of EAAs vs whey. The plasma proteomics data was generated using SOMA scan assay. A total of twenty proteins were found to be differentially expressed in both groups with a 1.5-fold change. Notably, five proteins showed a significantly higher fold change expression in the EAA group which included adenylate kinase isoenzyme 1, casein kinase II 2-alpha, Nascent polypeptide-associated complex subunit alpha, peroxiredoxin-1, and peroxiredoxin-6. These five proteins might have played a significant role in providing energy for the improved cardiac and muscle strength of older adults with LPF. On the other hand, fifteen proteins showed slightly lower fold change expression in the EAA group. Some of these 15 proteins regulate metabolism and were found to be associated with inflammation or other comorbidities. Gene Ontology (GO) enrichment analysis showed the association of these proteins with several biological processes. Furthermore, protein-protein interaction network analysis also showed distinct networks between upregulated and downregulated proteins. In conclusion, the important biological roles of the upregulated proteins plus better physical function of participants in the EAAs vs whey group demonstrated that EAAs have the potential to improve muscle strength and physical function in older adults. This study was registered with ClinicalTrials.gov: NCT03424265 "Nutritional interventions in heart failure."

Could SGLT2 Inhibitors Improve Exercise Intolerance in Chronic Heart Failure?

Despite the constant improvement of therapeutical options, heart failure (HF) remains associated with high mortality and morbidity. While new developments in guideline-recommended therapies can prolong survival and postpone HF hospitalizations, impaired exercise capacity remains one of the most debilitating symptoms of HF. Exercise intolerance in HF is multifactorial in origin, as the underlying cardiovascular pathology and reactive changes in skeletal muscle composition and metabolism both contribute. Recently, sodium-related glucose transporter 2 (SGLT2) inhibitors were found to improve cardiovascular outcomes significantly. Whilst much effort has been devoted to untangling the mechanisms responsible for these cardiovascular benefits of SGLT2 inhibitors, little is known about the effect of SGLT2 inhibitors on exercise performance in HF. This review provides an overview of the pathophysiological mechanisms that are responsible for exercise intolerance in HF, elaborates on the potential SGLT2-inhibitor-mediated effects on these phenomena, and provides an up-to-date overview of existing studies on the effect of SGLT2 inhibitors on clinical outcome parameters that are relevant to the assessment of exercise capacity. Finally, current gaps in the evidence and potential future perspectives on the effects of SGLT2 inhibitors on exercise intolerance in chronic HF are discussed.

Effects of Exercise on Heart Failure with Preserved Ejection Fraction: An Updated Review of Literature

Heart failure with preserved ejection fraction (HFpEF) represents the most common HF phenotype of patients aged > 65 years, with an incidence and a prevalence that are constantly growing. The HFpEF cardinal symptom is exercise intolerance (EI), defined as the impaired ability to perform physical activity and to reach the predicted age-related level of exercise duration in the absence of symptoms—such as fatigue or dyspnea—and is associated with a poor quality of life, a higher number of hospitalizations, and poor outcomes. The evidence of the protective effect between exercise and adverse cardiovascular outcomes is numerous and long-established. Regular exercise is known to reduce cardiovascular events and overall mortality both in apparently healthy individuals and in patients with established cardiovascular disease, representing a cornerstone in the prevention and treatment of many cardio-metabolic conditions. Several studies have investigated the role of exercise in HFpEF patients. The present review aims to dwell upon the effects of exercise on HFpEF. For this purpose, the relevant data from a literature search (PubMed, EMBASE, and Medline) were reviewed. The analysis of these studies underlines the fact that exercise training programs improve the cardiorespiratory performance of HFpEF patients in terms of the increase in peak oxygen uptake, the 6 min walk test distance, and the ventilatory threshold; on the other hand, diastolic or systolic functions are generally unchanged or only partially modified by exercise, suggesting that multiple mechanisms contribute to the improvement of exercise tolerance in HFpEF patients. In conclusion, considering that exercise training programs are able to improve the cardiorespiratory performance of HFpEF patients, the prescription of exercise training programs should be encouraged in stable HFpEF patients, and further research is needed to better elucidate the pathophysiological mechanisms underpinning the beneficial effects described.

Exercise Testing in HFpEF: an Appraisal Through Diagnosis, Pathophysiology and Therapy A Clinical Consensus Statement of the Heart Failure Association (HFA) and European Association of Preventive Cardiology (EAPC) of the European Society of Cardiology (ESC)

Patients with heart failure with preserved ejection fraction (HFpEF) universally complain of exercise intolerance and dyspnoea as key clinical correlates. Cardiac as well as extracardiac components play a role for the limited exercise capacity, including an impaired cardiac and peripheral vascular reserve, a limitation in mechanical ventilation and/or gas exchange with reduced pulmonary vascular reserve, skeletal muscle dysfunction and iron deficiency/anaemia. Although most of these components can be differentiated and quantified through gas exchange analysis by cardiopulmonary exercise testing (CPET), the information provided by objective measures of exercise performance have not been systematically considered in the recent algorithms/scores for HFpEF diagnosis, neither by European nor US groups. The current Clinical Consensus Statement by the HFA and EAPC Association of the ESC aims at outlining the role of exercise testing and its pathophysiological, clinical and prognostic insights, addressing the implication of a thorough functional evaluation from the diagnostic algorithm to the pathophysiology and treatment perspectives of HFpEF. Along with these goals, we provide a specific analysis on the evidence that CPET is the standard for assessing, quantifying, and differentiating the origin of dyspnoea and exercise impairment and even more so when combined with echo and/or invasive hemodynamic evaluation is here provided. This will lead to improved quality of diagnosis when applying the proposed scores and may also help useful to implement the progressive characterization of the specific HFpEF phenotypes, a critical step toward the delivery of phenotype-specific treatments.

Effects of exercise-based cardiac rehabilitation delivery modes on exercise capacity and health-related quality of life in heart failure: a systematic review and network meta-analysis

Background

This review aimed to compare the relative effectiveness of different exercise-based cardiac rehabilitation (ExCR) delivery modes (centre-based, home-based, hybrid and technology-enabled ExCR) on key heart failure (HF) outcomes: exercise capacity, health-related quality of life (HRQoL), HF-related hospitalisation and HF-related mortality.

Methods and results

Randomised controlled trials (RCTs) published through 20 June 2021 were identified from six databases, and reference lists of included studies. Risk of bias and certainty of evidence were evaluated using the Cochrane tool and Grading of Recommendations Assessment, Development and Evaluation, respectively. Bayesian network meta-analysis was performed using R. Continuous and binary outcomes are reported as mean differences (MD) and ORs, respectively, with 95% credible intervals (95% CrI). One-hundred and thirty-nine RCTs (n=18 670) were included in the analysis. Network meta-analysis demonstrated improvements in VO₂peak following centre-based (MD (95% CrI)=3.10 (2.56 to 3.65) mL/kg/min), home-based (MD=2.69 (1.67 to 3.70) mL/kg/min) and technology-enabled ExCR (MD=1.76 (0.27 to 3.26) mL/kg/min). Similarly, 6 min walk distance was improved following hybrid (MD=84.78 (31.64 to 138.32) m), centre-based (MD=50.35 (30.15 to 70.56) m) and home-based ExCR (MD=36.77 (12.47 to 61.29) m). Incremental shuttle walk distance did not improve following any ExCR delivery modes. Minnesota living with HF questionnaire improved after centre-based (MD=−10.38 (−14.15 to –6.46)) and home-based ExCR (MD=−8.80 (−13.62 to –4.07)). Kansas City Cardiomyopathy Questionnaire was improved following home-based ExCR (MD=20.61 (4.61 to 36.47)), and Short Form Survey 36 mental component after centre-based ExCR (MD=3.64 (0.30 to 6.14)). HF-related hospitalisation and mortality risks reduced only after centre-based ExCR (OR=0.41 (0.17 to 0.76) and OR=0.42 (0.16 to 0.90), respectively). Mean age of study participants was only associated with changes in VO₂peak.

Conclusion

ExCR programmes have broader benefits for people with HF and since different delivery modes were comparably effective for improving exercise capacity and HRQoL, the selection of delivery modes should be tailored to individuals’ preferences.

Estimation of Functional Aerobic Capacity Using the Sit-to-Stand Test in Older Adults with Heart Failure with Preserved Ejection Fraction

Background: The 6-Min Walking Test (6MWT) has been proposed to assess functional aerobic capacity in patients with heart failure, but many older adults with heart failure cannot complete it. The adequacy of the 5-repetition Sit-To-Stand (5-STS), a simpler test than 6MWT, to assess the functional aerobic capacity in older adults with heart failure has not been evaluated. Objectives: This study aimed to assess the usefulness of 5-STS in estimating maximal oxygen uptake (VO2 peak) in older adults with heart failure with preserved ejection fraction (HFpEF). Methods: A cross-sectional study was carried out. Patients 70 years and older with HFpEF were included. A bivariant Pearson correlation and subsequent multivariate linear regression analysis were used to analyze the correlations between the 5-STS and the estimated VO2 peak. Results: Seventy-six patients (80.74 (5.89) years) were recruited. The 5-STS showed a moderate and inversely correlation with the estimated VO2 peak (r = −0.555, p < 0.001). The 5-STS explained 40.4% of the variance in the estimated VO2 peak, adjusted by age, sex, and BMI. When older adults were stratified by BMI, the 5-STS explained 70% and 31.4% of the variance in the estimated VO2 peak in older adults with normal weight and overweight/obesity, respectively. Conclusions: The 5-STS may be an easy tool to assess functional aerobic capacity in older adults with HFpEF, especially for those with normal weight.

Physical Exercise Modalities for the Management of Heart Failure With Preserved Ejection Fraction: A Systematic Review and Meta-Analysis

ABSTRACT

Different physical exercise modalities have been widely studied in patients having heart failure with preserved ejection fraction (HFpEF) but with variably reported findings. We, therefore, conducted a systematic review and meta-analysis to evaluate whether the efficacy of physical activity in the management of HFpEF is related to exercise modalities. PubMed and Embase were searched up to July 2021. The eligible studies included randomized controlled trials that identified effects of physical exercise on patients with HFpEF. Sixteen studies were included to evaluate the efficiency of physical exercise in HFpEF. A pooled analysis showed that exercise training significantly improved peak oxygen uptake (VO2), ventilatory anaerobic threshold, distance covered in the 6-minute walking test, the ratio of early diastolic mitral inflow to annular velocities, the Short Form 36 physical component score, and the Minnesota Living with Heart Failure Questionnaire total score. However, the changes in other echocardiographic parameters including the ratio of peak early to late diastolic mitral inflow velocities, early diastolic mitral annular velocity, and left atrial volume index were not significant. Both high-intensity and moderate-intensity training significantly improved exercise capacity (as defined by peak VO2), with moderate-intensity exercise having a superior effect. Furthermore, exercise-induced improvement in peak VO2 was partially correlated with exercise duration. Physical exercise could substantially improve exercise capacity, quality of life, and some indicators of cardiac diastolic function in patients with HFpEF. A protocol of moderate-intensity exercise training lasting a longer duration might be more beneficial compared with high-intensity training for patients with HFpEF.

The HEART Camp Exercise Intervention Improves Exercise Adherence, Physical Function, and Patient-Reported Outcomes in Adults With Preserved Ejection Fraction Heart Failure

BACKGROUND

Despite exercise being one of few strategies to improve outcomes for individuals with heart failure with preserved ejection fraction (HFpEF), exercise clinical trials in HFpEF are plagued by poor interventional adherence. Over the last 2 decades, our research team has developed, tested, and refined Heart failure Exercise And Resistance Training (HEART) Camp, a multicomponent behavioral intervention to promote adherence to exercise in HF. We evaluated the effects of this intervention designed to promote adherence to exercise in HF focusing on subgroups of participants with HFpEF and heart failure with reduced ejection fraction (HFrEF).

METHODS AND RESULTS

This randomized controlled trial included 204 adults with stable, chronic HF. Of those enrolled, 59 had HFpEF and 145 had HFrEF. We tested adherence to exercise (defined as ≥120 minutes of moderate-intensity [40%-80% of heart rate reserve] exercise per week validated with a heart rate monitor) at 6, 12, and 18 months. We also tested intervention effects on symptoms (Patient-Reported Outcomes Measurement Information System-29 and dyspnea-fatigue index), HF-related health status (Kansas City Cardiomyopathy Questionnaire), and physical function (6-minute walk test). Participants with HFpEF (n = 59) were a mean of 64.6 ± 9.3 years old, 54% male, and 46% non-White with a mean ejection fraction of 55 ± 6%. Participants with HFpEF in the HEART Camp intervention group had significantly greater adherence compared with enhanced usual care at both 12 (43% vs 14%, phi = 0.32, medium effect) and 18 months (56% vs 0%, phi = 0.67, large effect). HEART Camp significantly improved walking distance on the 6-minute walk test (η2 = 0.13, large effect) and the Kansas City Cardiomyopathy Questionnaire overall (η2 = 0.09, medium effect), clinical summary (η2 = 0.16, large effect), and total symptom (η2 = 0.14, large effect) scores. In the HFrEF subgroup, only patient-reported anxiety improved significantly in the intervention group.

CONCLUSIONS

A multicomponent, behavioral intervention is associated with improvements in long-term adherence to exercise, physical function, and patient-reported outcomes in adults with HFpEF and anxiety in HFrEF. Our results provide a strong rationale for a large HFpEF clinical trial to validate these findings and examine interventional mechanisms and delivery modes that may further promote adherence and improve clinical outcomes in this population.

CLINICAL TRIAL REGISTRATION

URL: https://clinicaltrials.gov/. Unique identifier: NCT01658670.

Effects of different exercise programs on cardiorespiratory reserve in HFpEF: a systematic review and meta-analysis

HFpEF represents an heterogeneous syndrome with complex pathophysiologic substrate and multiple clinical manifestations. Much attention has been recently focused on cardiac rehabilitation programs for HFpEF patients and studies have examined the effects of exercise training on this specific population. This systematic review and meta-analysis included studies of adult patients with HFpEF and evaluated the impact of exercise on cardiorespiratory fitness variables measured during CPET. The primary outcome was the difference between groups in the change of peak oxygen uptake (Δpeak VO₂). Literature search involved PubMed/MEDLINE, Cochrane/CENTRAL and Scopus databases. From an initial 5,143 literature records, we identified 18 studies fulfilling inclusion criteria; 11 studies with 515 patients were finally included in primary outcome analysis. Δpeak VO₂ between baseline and study-end was significantly higher in the groups of exercise training versus control (WMD 2.25 ml/kg/min, 95%CI 1.81-2.70). Exercise training resulted in greater change in the 6MWT distance (WMD 2.25 meters, 95%CI 1.81-2.70). Health related quality of life (WMD: -3.36, 95%CI -9.42-2.70, I²=14%, p=0.33) and echocardiographic indexes of diastolic function showed no differences between exercise and control groups at study end. In subgroup analysis, no difference between resistance versus aerobic exercise was noted on Δpeak VO₂, but high intensity interval training showed greater increase in peak VO₂ versus aerobic exercise (WMD 1.62 ml/kg/min, 95%CI 0.96-2.29, I²=0%, p=0.82). Exercise training in HFpEF results in significant improvements in peak VO₂ and 6MWT distance compared to controls. High intensity interval training may offer greater enhancement of exercise capacity of these patients than standard aerobic exercise.

Effects of exercise training in heart failure with preserved ejection fraction: an updated systematic literature review

Physical activity is associated with a lower risk of adverse cardiovascular outcomes, including heart failure (HF). Exercise training is a class IA level recommendation in patients with stable HF, but its impact is less clear in heart failure with preserved ejection fraction (HFpEF). The aim of this study was to analyze the effects of the exercise training on cardiovascular outcomes in patients with HFpEF. A systematic literature search was conducted on the main electronic databases, proceedings of major meetings, and reference lists of the identified studies, using specific terms for only English language studies published between 2000 and 2018. We followed the PRISMA to perform our review. Quality of studies was also assessed. The systematic review identified 9 studies on 348 patients, of moderate (n = 2) to good (n = 7) quality. The training consisted of a combination of supervised in-hospital and home-based outpatient programs, including aerobic exercise, endurance and resistance training, walking, and treadmill and bicycle ergometer. Most of the protocols ranged 12-16 weeks, with a frequency of 2-3 sessions weekly, lasting 20-60 min per session. There were significant improvements in peak oxygen uptake, 6-min walking test distance, and ventilatory threshold, whereas quality of life and echocardiographic parameters improved only in some studies. Endothelial function/arterial stiffness remained unchanged. No adverse events were reported. Appropriate exercise programs are able to get a favorable cardiovascular outcome in patients with HFpEF. This could also benefit in terms of quality of life, even if more controversial. Further researches are necessary.

Exercise Intolerance in Heart Failure with Preserved Ejection Fraction

Exercise intolerance represents a typical feature of heart failure with preserved ejection fraction (HFpEF), and is associated with a poor quality of life, frequent hospitalizations, and increased all-cause mortality. The cardiopulmonary exercise test is the best method to quantify exercise intolerance, and allows detection of the main mechanism responsible for the exercise limitation, influencing treatment and prognosis. Exercise training programs improve exercise tolerance in HFpEF. However, studies are needed to identify appropriate type and duration. This article discusses the pathophysiology of exercise limitation in HFpEF, describes methods of determining exercise tolerance class, and evaluates prognostic implications and potential therapeutic strategies.

Daily Consumption of a Specially Formulated Essential Amino Acid-Based Dietary Supplement Improves Physical Performance in Older Adults With Low Physical Functioning

We have investigated the hypothesis that nutritional supplementation of the diet in low-physical-functioning older individuals with a specially formulated composition based on essential amino acids (EAAs) would improve physical function as compared to supplementation with the same amount of whey protein. A third group of comparable volunteers were given nutrition education but no supplementation of the diet. After 6 weeks of whey protein supplementation (n = 32), there was no effect on the distance walked in 6 minutes, but the distance walked improved significantly from the pre-value after 12 weeks of whey supplementation. EAA consumption (n = 28) significantly improved walking distance at both 6 and 12 weeks. The distance walked at 12 weeks (419.0 ± 25.0 m) was 35.4 m greater than the pre-value of 384.0 ± 23.0 m (p < .001). The increase in distance walked by the EAA group was also significantly greater than that in the whey group at both 6 and 12 weeks (p < .01). In contrast, a decrease in distance walked was observed in the control group (n = 32) (not statistically significant, NS). EAA supplementation also improved grip strength and leg strength, and decreased body weight and fat mass. Plasma low-density lipoprotein concentration was significantly reduced in the EAA group, as well as the concentration of macrophage migration inhibitory factor. There were no adverse responses in any groups, and compliance was greater than 95% in all individuals consuming supplements. We conclude that dietary supplementation with an EAA-based composition may be a beneficial therapy in older individuals with low physical functional capacity. Clinical Trials Registration Number: This study was registered with ClinicalTrials.gov: NCT03424265-"Nutritional interventions in heart failure."

Impaired Exercise Tolerance in Heart Failure With Preserved Ejection Fraction: Quantification of Multiorgan System Reserve Capacity

Exercise intolerance is a principal feature of heart failure with preserved ejection fraction (HFpEF), whether or not there is evidence of congestion at rest. The degree of functional limitation observed in HFpEF is comparable to patients with advanced heart failure and reduced ejection fraction. Exercise intolerance in HFpEF is characterized by impairments in the physiological reserve capacity of multiple organ systems, but the relative cardiac and extracardiac deficits vary among individuals. Detailed measurements made during exercise are necessary to identify and rank-order the multiorgan system limitations in reserve capacity that culminate in exertional intolerance in a given person. We use a case-based approach to comprehensively review mechanisms of exercise intolerance and optimal approaches to evaluate exercise capacity in HFpEF. We also summarize recent and ongoing trials of novel devices, drugs, and behavioral interventions that aim to improve specific exercise measures such as peak oxygen uptake, 6-min walk distance, heart rate, and hemodynamic profiles in HFpEF. Evaluation during the clinically relevant physiological perturbation of exercise holds promise to improve the precision with which HFpEF is defined and therapeutically targeted.

Wearable devices can predict the outcome of standardized 6-minute walk tests in heart disease

Wrist-worn devices with heart rate monitoring have become increasingly popular. Although current guidelines advise to consider clinical symptoms and exercise tolerance during decision-making in heart disease, it remains unknown to which extent wearables can help to determine such functional capacity measures. In clinical settings, the 6-minute walk test has become a standardized diagnostic and prognostic marker. We aimed to explore, whether 6-minute walk distances can be predicted by wrist-worn devices in patients with different stages of mitral and aortic valve disease. A total of n = 107 sensor datasets with 1,019,748 min of recordings were analysed. Based on heart rate recordings and literature information, activity levels were determined and compared to results from a 6-minute walk test. The percentage of time spent in moderate activity was a predictor for the achievement of gender, age and body mass index-specific 6-minute walk distances (p < 0.001; R 2 = 0.48). The uncertainty of these predictions is demonstrated.

Effect of Aerobic Exercise on Peak Oxygen Consumption, VE/VCO2 Slope, and Health-Related Quality of Life in Patients with Heart Failure with Preserved Left Ventricular Ejection Fraction: a Systematic Review and Meta-Analysis

PURPOSE OF REVIEW

The aim of this study was to determine the effects of aerobic exercise on peak oxygen uptake (peak VO₂), minute ventilation/carbon dioxide production (VE/VCO₂ slope), and health-related quality of life (HRQoL) among patients with heart failure (HF) and preserved ejection fraction (HFpEF).

RECENT FINDINGS

We conducted a Cochrane Library, MEDLINE/PubMed, Physiotherapy Evidence Database, and SciELO search (from 1985 to May 2019) for randomized controlled trials that evaluated the effects of aerobic exercise in HFpEF patients. We calculated the mean differences (MD) and 95% confidence interval (CI). Ten intervention studies were included providing a total of 399 patients. Compared with control, aerobic exercise resulted in improvement in peak VO₂ MD 1.9 mL kg^-1 min^-1 (95% CI 1.3 to 2.5; N = 314) and HRQoL measured by Minnesota Living with Heart Failure MD 5.4 (95% CI - 10.5 to - 0.2; N = 256). No significant difference in VE/VCO₂ slope was found between participants in the aerobic exercise group and the control group. The quality of evidence for peak VO₂ and HRQoL was assessed as being moderate. Aerobic exercise moderately improves peak VO₂ and HRQoL and should be considered a strategy of rehabilitation of HFpEF individuals.

Respiratory training interventions improve health status of heart failure patients: A systematic review and network meta-analysis of randomized controlled trials

BACKGROUND

Prior studies indicate that doing breathing exercises improves physical performance and quality of life (QoL) in heart failure patients. However, these effects remain unclear and contradictory.

AIM

To determine the effects of machine-assisted and non-machine-assisted respiratory training on physical performance and QoL in heart failure patients.

METHODS

This was a systematic review and network meta-analysis study. A literature search of electronic databases was conducted for randomized controlled trials (RCTs) on heart failure. Respiratory training interventions were grouped as seven categories: IMT_Pn (inspiratory muscle training without pressure or < 10% maximal inspiratory pressure, MIP), IMT_Pl (inspiratory muscle training with low pressure, 10%-15% MIP), IMT_Pm (inspiratory muscle training with medium pressure, 30%-40% MIP), IMT_Ph (inspiratory muscle training with high pressure, 60% MIP or MIP plus aerobics), Aerobics (aerobic exercise or weight training), Qi_Ex (tai chi, yoga, and breathing exercise), and none. The four outcomes were heart rate, peak oxygen uptake (VO₂ peak), 6-min walking distance test (6MWT), and Minnesota Living with Heart Failure QoL. The random-effects model, side-splitting model, and the surface under the cumulative ranking curve (SUCRA) were used to test and analyze the data.

RESULTS

A total of 1499 subjects from 31 RCT studies were included. IMT_Ph had the highest effect sizes for VO₂ peak and 6MWT, IMT_Pm highest for QoL, and Qi_Ex highest for heart rate. Aerobics had the second highest for VO₂ peak, Qi_Ex second highest for 6MWT, and IMT_Ph second highest for heart rate and QoL.

CONCLUSION

This study supports that high- and medium-intensity machine-assisted training improves exercise capacity and QoL in hospital-based heart failure patients. After hospital discharge, non-machine-assisted training continuously improves cardiac function.

6-minute walking test: a useful tool in the management of heart failure patients

Reduced functional ability and exercise tolerance in patients with heart failure (HF) are associated with poor quality of life and a worse prognosis. The 6-minute walking test (6MWT) is a widely available and well-tolerated test for the assessment of the functional capacity of patients with HF. Although the cardiopulmonary exercise test (a maximal exercise test) remains the gold standard for the evaluation of exercise capacity in patients with HF, the 6MWT (submaximal exercise test) may provide reliable information about the patient’s daily activity. The current review summarizes the value of 6MWT in patients with HF and identifies its usefulness and limitations in everyday clinical practice in populations of HF. We aimed to investigate potential associations of 6MWD with other measures of functional status and determinants of 6MWD in patients with HF as well as to review its prognostic role and changes to various interventions in these patients.

Effect of Neladenoson Bialanate on Exercise Capacity Among Patients With Heart Failure With Preserved Ejection Fraction: A Randomized Clinical Trial

IMPORTANCE

Heart failure with preserved ejection fraction (HFpEF) lacks effective treatments. Based on preclinical studies, neladenoson bialanate, a first-in-class partial adenosine A1 receptor agonist, has the potential to improve several heart failure-related cardiac and noncardiac abnormalities but has not been evaluated to treat HFpEF.

OBJECTIVES

To determine whether neladenoson improves exercise capacity, physical activity, cardiac biomarkers, and quality of life in patients with HFpEF and to find the optimal dose.

DESIGN, SETTING, AND PARTICIPANTS

Phase 2b randomized clinical trial conducted at 76 centers in the United States, Europe, and Japan. Patients (N = 305) with New York Heart Association class II or III HFpEF with elevated natriuretic peptide levels were enrolled between May 10, 2017, and December 7, 2017 (date of final follow-up: June 20, 2018).

INTERVENTIONS

Participants were randomized (1:2:2:2:2:3) to neladenoson (n = 27 [5 mg], n = 50 [10 mg], n = 51 [20 mg], n = 50 [30 mg], and n = 51 [40 mg]) or matching placebo (n = 76) for 20 weeks of treatment.

MAIN OUTCOMES AND MEASURES

The primary end point was change in 6-minute walk test distance from baseline to 20 weeks (minimal clinically important difference, 40 m). Key safety measures included bradyarrhythmias and adverse events. To evaluate the effects of varying doses of neladenoson, a multiple comparison procedure with 5 modeling techniques (linear, Emax, 2 variations of sigmoidal Emax, and quadratic) was used to evaluate diverse dose-response profiles.

RESULTS

Among 305 patients who were randomized (mean age, 74 years; 160 [53%] women; mean 6-minute walk test distance, 321.5 m), 261 (86%) completed the trial and were included in the primary analysis. After 20 weeks of treatment, the mean absolute changes from baseline in 6-minute walk test distance were 0.2 m (95% CI, -12.1 to 12.4 m) for the placebo group; 19.4 m (95% CI, -10.8 to 49.7 m) for the 5 mg of neladenoson group; 29.4 m (95% CI, 3.0 to 55.8 m) for 10 mg of neladenoson group; 13.8 m (95% CI, -2.3 to 29.8 m) for 20 mg of neladenoson group; 16.3 m (95% CI, -1.1 to 33.6 m) for 30 mg of neladenoson group; and 13.0 m (95% CI, -5.9 to 31.9 m) for 40 mg of neladenoson group. Because none of the neladenoson groups achieved the clinically relevant 40-m increase in 6-minute walk test distance from baseline, an optimal dose of neladenoson was not identified. There was no significant dose-response relationship for the change in 6-minute walk test distance among the 5 different dose-response models (P = .05 for Emax; P = .18 for quadratic; P = .21 for sigmoidal Emax 1; P = .39 for linear; and P = .52 for sigmoidal Emax 2). Serious adverse events were similar among the neladenoson groups (61/229 [26.6%]) and the placebo group (21/76 [27.6%]).

CONCLUSIONS AND RELEVANCE

Among patients with HFpEF, there was no significant dose-response relationship detected for neladenoson with regard to the change in exercise capacity from baseline to 20 weeks. In light of these findings, novel approaches will be needed if further development of neladenoson for the treatment of patients with HFpEF is pursued.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03098979.

Rationale and design of the phase 2b clinical trials to study the effects of the partial adenosine A1-receptor agonist neladenoson bialanate in patients with chronic heart failure with reduced (PANTHEON) and preserved (PANACHE) ejection fraction

Despite major advances in the treatment of chronic heart failure (HF) with reduced ejection fraction (HFrEF), morbidity and mortality associated with the condition remain high, suggesting the need for additional treatment options, particularly haemodynamically neutral treatments that do not alter blood pressure, heart rate, or renal function. HF with preserved ejection fraction (HFpEF) is also associated with high morbidity and mortality and adequate treatment options are limited; thus there is a critical unmet need for the development of novel therapies for HFpEF. Chronic HFrEF and HFpEF are both systemic disorders that affect not only the heart but several other tissues and organs including skeletal muscle, leading to exercise intolerance and dyspnoea. Partial adenosine A1-receptor agonists represent a novel potential therapy for HF regardless of underlying ejection fraction given their minimal effect on heart rate and blood pressure, and preclinical data demonstrate several possible beneficial mechanisms, including improved mitochondrial function and sarcoplasmic reticulum Ca²⁺ -ATPase (SERCA2a) activity, enhanced energy substrate utilization, reverse ventricular remodelling, and anti-ischemic, cardioprotective properties. However, data on this class of drugs in humans are scarce, and the optimal dose of the partial adenosine A1 receptor, neladenoson bialanate, has not been defined. Here we describe the design and rationale of two randomized, double-blind, placebo-controlled, parallel-group, dose-finding phase 2b trials, PANTHEON (HFrEF) and PANACHE (HFpEF), that will advance our understanding of the potential benefit and optimal dose of neladenoson bialanate and provide critical information for the planning of future phase 3 trials.

Six-Minute Walk Test for Assessing Physical Functional Capacity in Chronic Heart Failure

PURPOSE OF THE REVIEW

The six-minute walk test (6MWT) is a submaximal exercise test for evaluating physical functional capacity. This review aims to report the research on the use of the 6MWT in chronic heart failure (CHF) that has been published in the past 5 years.

RECENT FINDINGS

The 6MWT distance does not accurately reflect peak VO₂. Minimal clinically important difference in the 6MWT distance, and additional measurements, such as heart rate recovery, can assist in the interpretation of the 6MWT distance, so management decisions can be made. Incorporating mobile apps and information technology in measuring the 6MWT distance extends the usefulness of this simple walk test and improve remote monitoring of patients with CHF. The 6MWT is a useful tool in CHF programs. However, interpretation of the 6MWT distance must be with caution. With the advancement in technology, the 6MWT has the potential to facilitate the monitoring of people living in rural and remote areas.

Resting and exercise haemodynamics in relation to six-minute walk test in patients with heart failure and preserved ejection fraction

AIMS

Patients with heart failure and preserved ejection fraction (HFpEF) are characterized by functional impairment and an abnormal haemodynamic response to exercise. The six-minute walk test (6MWT) serves as a standardized test for functional capacity quantification in heart failure patients, and is associated with cardiovascular outcomes. However, as the association between 6MWT and haemodynamic parameters during rest and exercise in HFpEF patients is unknown, we sought to elucidate this relationship.

METHODS AND RESULTS

Overall, 64 patients enrolled in the REDUCE LAP-HF trial completed a 6MWT at baseline. Univariate and multivariable linear regression models were used to assess the associations between 6MWT and measured or derived haemodynamic variables at baseline, during light/moderate exercise (20 W), and at peak supine exercise. The average 6MWT distance was 318 ± 106 m. At rest, in a multivariable model, only pulmonary capillary wedge pressure (PCWP) was significantly associated with 6MWT [coefficient: -5.4, 95% confidence interval (CI) -10.4, -0.5, P = 0.033]. During light/moderate exercise, mean pulmonary artery pressure was associated with 6MWT in a multivariable model (coefficient: -3.5, 95% CI -6.8, -0.3, P = 0.033). During peak exercise, central venous pressure, cardiac index (CI), and PCWP/CI correlated with 6MWT; however, workload corrected PCWP was the only variable independently associated with 6MWT (coefficient: -0.8, 95% CI -1.3, -0.4, P < 0.001). The variance in 6MWT was modestly explained by measured or derived haemodynamic variables at rest or at any stage of exercise (r²  = 7-17%).

CONCLUSION

Workload corrected PCWP correlated best with 6MWT performance in HFpEF patients. Baseline haemodynamic variables were modestly correlated with 6MWT, suggesting that 6MWT performance in HFpEF patients may be significantly influenced by extra-cardiac factors.

The link between exercise and titin passive stiffness

NEW FINDINGS

What is the topic of this review? This review focuses on how in vivo and molecular measurements of cardiac passive stiffness can predict exercise tolerance and how exercise training can reduce cardiac passive stiffness. What advances does it highlight? This review highlights advances in understanding the relationship between molecular (titin-based) and in vivo (left ventricular) passive stiffness, how passive stiffness modifies exercise tolerance, and how exercise training may be therapeutic for cardiac diseases with increased passive stiffness. Exercise can help alleviate the negative effects of cardiovascular disease and cardiovascular co-morbidities associated with sedentary behaviour; this may be especially true in diseases that are associated with increased left ventricular passive stiffness. In this review, we discuss the inverse relationship between exercise tolerance and cardiac passive stiffness. Passive stiffness is the physical property of cardiac muscle to produce a resistive force when stretched, which, in vivo, is measured using the left ventricular end diastolic pressure-volume relationship or is estimated using echocardiography. The giant elastic protein titin is the major contributor to passive stiffness at physiological muscle (sarcomere) lengths. Passive stiffness can be modified by altering titin isoform size or by post-translational modifications. In both human and animal models, increased left ventricular passive stiffness is associated with reduced exercise tolerance due to impaired diastolic filling, suggesting that increased passive stiffness predicts reduced exercise tolerance. At the same time, exercise training itself may induce both short- and long-term changes in titin-based passive stiffness, suggesting that exercise may be a treatment for diseases associated with increased passive stiffness. Direct modification of passive stiffness to improve exercise tolerance is a potential therapeutic approach. Titin passive stiffness itself may be a treatment target based on the recent discovery of RNA binding motif 20, which modifies titin isoform size and passive stiffness. Translating these discoveries that link exercise and left ventricular passive stiffness may provide new methods to enhance exercise tolerance and treat patients with cardiovascular disease.