Comparison of Treadmill and Cycle Ergometer Exercise During Cardiac Rehabilitation: A Meta-analysis

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 .

Home-based versus centre-based cardiac rehabilitation

BACKGROUND

Cardiovascular disease is the most common cause of death globally. Traditionally, centre-based cardiac rehabilitation programmes are offered to individuals after cardiac events to aid recovery and prevent further cardiac illness. Home-based and technology-supported cardiac rehabilitation programmes have been introduced in an attempt to widen access and participation, especially during the SARS-CoV-2 pandemic. This is an update of a review previously published in 2009, 2015, and 2017.

OBJECTIVES

To compare the effect of home-based (which may include digital/telehealth interventions) and supervised centre-based cardiac rehabilitation on mortality and morbidity, exercise-capacity, health-related quality of life, and modifiable cardiac risk factors in patients with heart disease SEARCH METHODS: We updated searches from the previous Cochrane Review by searching the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (Ovid), Embase (Ovid), PsycINFO (Ovid) and CINAHL (EBSCO) on 16 September 2022. We also searched two clinical trials registers as well as previous systematic reviews and reference lists of included studies. No language restrictions were applied.

SELECTION CRITERIA

We included randomised controlled trials that compared centre-based cardiac rehabilitation (e.g. hospital, sports/community centre) with home-based programmes (± digital/telehealth platforms) in adults with myocardial infarction, angina, heart failure, or who had undergone revascularisation.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened all identified references for inclusion based on predefined inclusion criteria. Disagreements were resolved through discussion or by involving a third review author. Two authors independently extracted outcome data and study characteristics and assessed risk of bias. Certainty of evidence was assessed using GRADE.

MAIN RESULTS

We included three new trials in this update, bringing a total of 24 trials that have randomised a total of 3046 participants undergoing cardiac rehabilitation. A further nine studies were identified and are awaiting classification. Manual searching of trial registers until 16 September 2022 revealed a further 14 clinical trial registrations - these are ongoing. Participants had a history of acute myocardial infarction, revascularisation, or heart failure. Although there was little evidence of high risk of bias, a number of studies provided insufficient detail to enable assessment of potential risk of bias; in particular, details of generation and concealment of random allocation sequencing and blinding of outcome assessment were poorly reported. No evidence of a difference was seen between home- and centre-based cardiac rehabilitation in our primary outcomes up to 12 months of follow-up: total mortality (risk ratio [RR] = 1.19, 95% confidence interval [CI] 0.65 to 2.16; participants = 1647; studies = 12/comparisons = 14; low-certainty evidence) or exercise capacity (standardised mean difference (SMD) = -0.10, 95% CI -0.24 to 0.04; participants = 2343; studies = 24/comparisons = 28; low-certainty evidence). The majority of evidence (N=71 / 77 comparisons of either total or domain scores) showed no significant difference in health-related quality of life up to 24 months follow-up between home- and centre-based cardiac rehabilitation. Trials were generally of short duration, with only three studies reporting outcomes beyond 12 months (exercise capacity: SMD 0.11, 95% CI -0.01 to 0.23; participants = 1074; studies = 3; moderate-certainty evidence). There was a similar level of trial completion (RR 1.03, 95% CI 0.99 to 1.08; participants = 2638; studies = 22/comparisons = 26; low-certainty evidence) between home-based and centre-based participants. The cost per patient of centre- and home-based programmes was similar.

AUTHORS' CONCLUSIONS

This update supports previous conclusions that home- (± digital/telehealth platforms) and centre-based forms of cardiac rehabilitation formally supported by healthcare staff seem to be similarly effective in improving clinical and health-related quality of life outcomes in patients after myocardial infarction, or revascularisation, or with heart failure. This finding supports the continued expansion of healthcare professional supervised home-based cardiac rehabilitation programmes (± digital/telehealth platforms), especially important in the context of the ongoing global SARS-CoV-2 pandemic that has much limited patients in face-to-face access of hospital and community health services. Where settings are able to provide both supervised centre- and home-based programmes, consideration of the preference of the individual patient would seem appropriate. Although not included in the scope of this review, there is an increasing evidence base supporting the use of hybrid models that combine elements of both centre-based and home-based cardiac rehabilitation delivery. Further data are needed to determine: (1) whether the short-term effects of home/digital-telehealth and centre-based cardiac rehabilitation models of delivery can be confirmed in the longer term; (2) the relative clinical effectiveness and safety of home-based programmes for other heart patients, e.g. post-valve surgery and atrial fibrillation.

Comparison of Cardiovascular Response to Lower Body and Whole Body Exercise Among Sedentary Young Adults

Background Cardiovascular responses to exercise are essential indicators of cardiovascular health and fitness. Understanding how different types of exercise, such as lower-body and whole-body exercises, impact these responses is crucial for designing effective fitness programs and assessing cardiovascular function. Aim This study aimed to compare the cardiovascular response of young adults during lower-body exercise using a bicycle ergometer and whole-body exercise on a treadmill. Methods Thirty-two healthy young adults participated in this study. Each participant completed two exercise sessions on separate days: lower-body exercise on a bicycle ergometer with a fixed cadence of 60 rpm with a breaking resistance of 1.75 kg and whole-body exercise on a treadmill with a speed of 1.7 mph and a 10% grade. Heart rate (HR), systolic blood pressure (BP), and diastolic BP were measured at rest and immediately after a three-minute exercise. Data were analyzed using paired t-tests to compare the cardiovascular responses between the two exercise modalities. Results A total of 17 male and 15 female young adults with a mean age of 20.87±1.43 years participated in the study. The male and female participants had similar ages (p =0.56) and body mass indexes (p = 0.1). There was a higher HR (129.16±2.67 versus 150.87±3.23, p<0.0001) and systolic BP (127.29±2.34 versus 144.9±4.16, p<0.0001) and lower diastolic BP (68.97±2.41 versus 62.97±2.31, p<0.0001) in whole body exercise on treadmill compared to lower body exercise in bicycle ergometer. The effect size was large enough as Cohen's d was 7.33, 5.13, and 2.54 for HR, systolic BP, and diastolic BP, respectively. Conclusion In sedentary young adults, treadmill exercise led to higher HR, systolic BP, and lower diastolic BP than bicycle ergometer exercise. Increased muscle recruitment might result in higher energy expenditure, increasing the HR and systolic BP to deliver oxygen and nutrients to the working muscles. Further research is needed to understand the mechanisms and long-term implications for precise exercise recommendations and better cardiovascular health management.

Maximal oxygen uptake prediction from submaximal bicycle ergometry using a differential model

The maximal oxygen uptake (VO₂max) estimation has been a subject of research for many years. Cardiorespiratory measurements during incremental tests until exhaustion are considered the golden yard stick to assess VO₂max. However, precise VO₂max determination based on submaximal tests is attractive for athlete as well for clinical populations. Here, we propose and verify such a method based on experimental data. Using a recently developed model of heart rate (HR) and VO₂ kinetics in graded exercise tests, we applied a protocol, which is terminated at 80% of the estimated maximal HR during ergometer cycling. In our approach, initially, formula for maximal HR is selected by retrospective study of a reference population (17 males, 23.5 ± 2.0 years, BMI: 23.9 ± 3.2 kg/m²). Next, the subjects for experimental group were invited (nine subjects of both sexes: 25.1 ± 2.1 years, BMI 23.2 ± 2.2 kg/m²). After calculation of maximal HR using cardiorespiratory recordings from the submaximal test, VO₂max is predicted. Finally, we compared the prediction with the values from the maximal exercise test. The differences were quantified by relative errors, which vary from 1.2% up to 13.4%. Some future improvements for the procedure of VO₂max prediction are discussed. The experimental protocol may be useful for application in rehabilitation assessment and in certain training monitoring settings, since physical exertion is not a prerequisite and the approach provides an acceptable VO₂max estimation accuracy.

HRV-Guided Training for Elders after Stroke: A Protocol for a Cluster-Randomized Controlled Trial

There are many consequences associated with having a stroke, all of which are important factors affecting long-term rehabilitation outcomes; these become important health issues for those of advanced age and require dedicated health strategies. High-intensity interval training (HIIT) is an effective training protocol used in cardiac rehabilitation programs; however, owing to the inter-individual variability in physiological responses to training associated with cardiovascular diseases, the exercise regimen given to each patient should be closely controlled and individualized to ensure the safety and efficiency of the exercise program. Heart rate variability (HRV) is currently being used for this purpose, as it is closely linked to parasympathetic nervous system activation, with high HRV scores associated with good cardiovascular adaptation. The objective of this protocol is to determine the effect of HIIT compared to HRV-guided training in terms of cardiorespiratory fitness, heart rate variability, functional parameters, body composition, quality of life, inflammatory markers, and cognitive function in patients who have had a stroke, as well as to assess the feasibility of patients undertaking an 8-week cardiac rehabilitation program, evaluating its safety and their adherence. The proposed protocol involved cluster-randomized controlled design in which the post-stroke patients are assigned either to an HRV-based training group (HRV-G) or a HIIT-based training group (HIIT-G). HIIT-G will train according to a predefined training program, whereas HRV-G will train depending on the patients' daily HRV. The outcomes considered are peak oxygen uptake (VO_2peak), endothelial and work parameters, heart rate variability, functional parameters, relative weight and body fat distribution, quality of life, inflammatory markers and cognitive function, as well as exercise adherence, feasibility, and safety. It is expected that this HRV-guided training protocol will improve functional performance in patients following a stroke and be safer, more feasible, and generate improved adherence relative to HIIT, providing an improved strategy for to optimize cardiac rehabilitation interventions.

Optimal exercise training for children with congenital heart disease: A systematic review

Background

Although more children with congenital heart disease (CHD) are reaching adulthood, they generally have some impairment compared to their healthy peers. Few studies have investigated the effect of exercise training on health-related quality of life (HRQOL) and/or physical activity in children with CHD.

Purpose

The purpose of this study was to systematically review the effect of exercise training on HRQOL and/or physical activity and the types of training used in general.

Methods

We searched relevant articles published from 2000 to 2021 in English and included intervention studies for children with CHD younger than 20 years who underwent exercise training. Afterwards, we excluded the studies not using HRQOL or physical activity as outcome measures, classified the extracted information according to outcome measures and types of interventions, and assessed the risk of bias of the included studies.

Results

Finally, 10 articles were selected, and HRQOL in 3 articles and physical activity in 3 articles showed improvement after exercise training. However, 4 articles did not show improvement in these outcome measures, and 9 of the articles had a high risk of bias in blinding. Sport-based or play-based interventions were used in 5 articles, and prescribed or structured ones were used in 5 articles.

Conclusion

Although exercise training for children with CHD may improve their HRQOL and/or physical activity, more studies are needed to assess the effect statistically. In children with CHD, sport-based or play-based interventions could be used as well as prescribed or structured interventions.

Effect of High-Intensity Interval Training on Physical Health in Coronary Artery Disease Patients: A Meta-Analysis of Randomized Controlled Trials

The effects of exercise-based cardiac rehabilitation (CR) on physical health in coronary artery disease (CAD) patients has long been established, while the optimal exercise mode remains to be determined. This meta-analysis compared the efficacy of high-intensity interval training (HIIT) versus moderate-intensity continuous training (MICT) in CAD patients. Databases were searched up to December 2020. Twenty-five studies with 1272 participants were analyzed. The results showed that both HIIT and MICT induced significant VO_2peak improvement with a 4.52 mL/kg/min (p < 0.01) and 2.36 mL/kg/min (p < 0.01), respectively. Additionally, a larger improvement of VO_2peak (1.92 mL/kg/min, p < 0.01) was observed in HIIT over MICT. HIIT with medium and long intervals, higher work/rest ratio induced larger VO_2peak improvement than the compared subgroup. Interestingly, non-isocaloric exercise protocols induced larger VO_2peak improvement compared with isocaloric protocols. In addition, both HIIT and MICT significantly increased anaerobic threshold and peak power with HIIT superior to MICT. No significant different changes were observed in blood pressure after HIIT or MICT intervention, however when HIIT was compared with MICT, MICT seems superior to HIIT in reducing systolic blood pressure (−3.61 mmHg, p < 0.01) and diastolic blood pressure (−2.37 mmHg, p < 0.01). Although, HIIT and MICT induced significant improvement of most other parameters, like HR_rest, HR_peak, left ventricular ejection fraction (LVEF), quality of life (QoL), no significant differences were noted between groups. This meta-analysis suggested that HIIT is superior to MICT in increasing VO_2peak, anaerobic threshold, peak power in CAD patients. Additionally, the efficacy of HIIT over MICT in improving VO_2peaks was influenced by HIIT intervals, work/rest ratio and total caloric consumption. Both HIIT and MICT did not significantly influence resting BP, however, MICT seemed to be more effective in reducing BP than HIIT. HIIT and MICT equally significantly influenced HR_rest, HR_peak, HRR1min, OUES, LVEF%, QoL.

Exercise-based cardiac rehabilitation for coronary heart disease

BACKGROUND

Coronary heart disease (CHD) is the most common cause of death globally. However, with falling CHD mortality rates, an increasing number of people living with CHD may need support to manage their symptoms and prognosis. Exercise-based cardiac rehabilitation (CR) aims to improve the health and outcomes of people with CHD. This is an update of a Cochrane Review previously published in 2016.

OBJECTIVES

To assess the clinical effectiveness and cost-effectiveness of exercise-based CR (exercise training alone or in combination with psychosocial or educational interventions) compared with 'no exercise' control, on mortality, morbidity and health-related quality of life (HRQoL) in people with CHD.

SEARCH METHODS

We updated searches from the previous Cochrane Review, by searching CENTRAL, MEDLINE, Embase, and two other databases in September 2020. We also searched two clinical trials registers in June 2021.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) of exercise-based interventions with at least six months' follow-up, compared with 'no exercise' control. The study population comprised adult men and women who have had a myocardial infarction (MI), coronary artery bypass graft (CABG) or percutaneous coronary intervention (PCI), or have angina pectoris, or coronary artery disease.

DATA COLLECTION AND ANALYSIS

We screened all identified references, extracted data and assessed risk of bias according to Cochrane methods. We stratified meta-analysis by duration of follow-up: short-term (6 to 12 months); medium-term (> 12 to 36 months); and long-term ( > 3 years), and used meta-regression to explore potential treatment effect modifiers. We used GRADE for primary outcomes at 6 to 12 months (the most common follow-up time point).  MAIN RESULTS: This review included 85 trials which randomised 23,430 people with CHD. This latest update identified 22 new trials (7795 participants). The population included predominantly post-MI and post-revascularisation patients, with a mean age ranging from 47 to 77 years. In the last decade, the median percentage of women with CHD has increased from 11% to 17%, but females still account for a similarly small percentage of participants recruited overall ( < 15%). Twenty-one of the included trials were performed in low- and middle-income countries (LMICs). Overall trial reporting was poor, although there was evidence of an improvement in quality over the last decade. The median longest follow-up time was 12 months (range 6 months to 19 years). At short-term follow-up (6 to 12 months), exercise-based CR likely results in a slight reduction in all-cause mortality (risk ratio (RR) 0.87, 95% confidence interval (CI) 0.73 to 1.04; 25 trials; moderate certainty evidence), a large reduction in MI (RR 0.72, 95% CI 0.55 to 0.93; 22 trials; number needed to treat for an additional beneficial outcome (NNTB) 75, 95% CI 47 to 298; high certainty evidence), and a large reduction in all-cause hospitalisation (RR 0.58, 95% CI 0.43 to 0.77; 14 trials;  NNTB 12, 95% CI 9 to 21; moderate certainty evidence). Exercise-based CR likely results in little to no difference in risk of cardiovascular mortality (RR 0.88, 95% CI 0.68 to 1.14; 15 trials; moderate certainty evidence), CABG (RR 0.99, 95% CI 0.78 to 1.27; 20 trials; high certainty evidence), and PCI (RR 0.86, 95% CI 0.63 to 1.19; 13 trials; moderate certainty evidence) up to 12 months' follow-up. We are uncertain about the effects of exercise-based CR on cardiovascular hospitalisation, with a wide confidence interval including considerable benefit as well as harm (RR 0.80, 95% CI 0.41 to 1.59; low certainty evidence). There was evidence of substantial heterogeneity across trials for cardiovascular hospitalisations (I2 = 53%), and of small study bias for all-cause hospitalisation, but not for all other outcomes. At medium-term follow-up, although there may be little to no difference in all-cause mortality (RR 0.90, 95% CI 0.80 to 1.02; 15 trials), MI (RR 1.07, 95% CI 0.91 to 1.27; 12 trials), PCI (RR 0.96, 95% CI 0.69 to 1.35; 6 trials), CABG (RR 0.97, 95% CI 0.77 to 1.23; 9 trials), and all-cause hospitalisation (RR 0.92, 95% CI 0.82 to 1.03; 9 trials), a large reduction in cardiovascular mortality was found (RR 0.77, 95% CI 0.63 to 0.93; 5 trials). Evidence is uncertain for difference in risk of cardiovascular hospitalisation (RR 0.92, 95% CI 0.76 to 1.12; 3 trials). At long-term follow-up, although there may be little to no difference in all-cause mortality (RR 0.91, 95% CI 0.75 to 1.10), exercise-based CR may result in a large reduction in cardiovascular mortality (RR 0.58, 95% CI 0.43 to 0.78; 8 trials) and MI (RR 0.67, 95% CI 0.50 to 0.90; 10 trials). Evidence is uncertain for CABG (RR 0.66, 95% CI 0.34 to 1.27; 4 trials), and PCI (RR 0.76, 95% CI 0.48 to 1.20; 3 trials). Meta-regression showed benefits in outcomes were independent of CHD case mix, type of CR, exercise dose, follow-up length, publication year, CR setting, study location, sample size or risk of bias. There was evidence that exercise-based CR may slightly increase HRQoL across several subscales (SF-36 mental component, physical functioning, physical performance, general health, vitality, social functioning and mental health scores) up to 12 months' follow-up; however, these may not be clinically important differences. The eight trial-based economic evaluation studies showed exercise-based CR to be a potentially cost-effective use of resources in terms of gain in quality-adjusted life years (QALYs).

AUTHORS' CONCLUSIONS

This updated Cochrane Review supports the conclusions of the previous version, that exercise-based CR provides important benefits to people with CHD, including reduced risk of MI, a likely small reduction in all-cause mortality, and a large reduction in all-cause hospitalisation, along with associated healthcare costs, and improved HRQoL up to 12 months' follow-up. Over longer-term follow-up, benefits may include reductions in cardiovascular mortality and MI. In the last decade, trials were more likely to include females, and be undertaken in LMICs, increasing the generalisability of findings. Well-designed, adequately-reported RCTs of CR in people with CHD more representative of usual clinical practice are still needed. Trials should explicitly report clinical outcomes, including mortality and hospital admissions, and include validated HRQoL outcome measures, especially over longer-term follow-up, and assess costs and cost-effectiveness.

Exercise-Based Interventions in Middle-Aged and Older Adults after Myocardial Infarction: A Systematic Review

This study summarized the relevant literature and aimed to determine the effect of exercise-based interventions after myocardial infarction in middle-aged and older adults. Studies were identified and analyzed according to the PRISMA guidelines. The following electronic databases were used: Google Scholar, PubMed, Mendeley, Science Direct, and Scopus. The identified studies had to be longitudinal, be published in English, have taken place between 2010 and 2020, involve participants who had suffered myocardial infarction, and address different types of exercise-based interventions to be included. Of the 592 relevant studies identified, 20 were included in the qualitative analysis. After analyzing the results obtained, it could be concluded that different types of exercise-based interventions or their combination have a positive effect after myocardial infarction in middle-aged and elderly adults. It can also be suggested that the combination of a cycle ergometer and a treadmill may be the most effective exercise-based intervention. An adequate choice of intensity and volume is crucial, with the optimal duration of the experimental program and the type(s) of exercises adapted to participants after myocardial infarction.