Quality of life and cardiorespiratory function in chronic heart failure: effects of 12 months' aerobic training

Ergophysiological evaluation of heart failure patients with reduced ejection fraction undergoing exercise-based cardiac rehabilitation: A systematic review and meta-analysis

BACKGROUND

This systematic review and meta-analysis aims to explore in heart failure (HF) patients with reduced ejection fraction (EF) undergoing exercise-based cardiac rehabilitation the following: 1) the comparison of temporal changes between peak oxygen uptake (VO2peak) and first ventilatory threshold (VO2VT1), 2) the association of VO2peak and VO2VT1 changes with physiological factors, and 3) the differential effects of continuous aerobic exercise (CAE) and interval training (IT) on VO2peak and VO2VT1.

METHODS

A systematic literature search was conducted in PubMed, CENTRAL, and Scopus. Inclusion criteria were 1) original research articles using exercise-based cardiac rehabilitation, 2) stable HF patients with reduced EF, 3) available values of VO2peak and VO2VT1 (in mL/kg/min) both at baseline and after exercise training with comparison between these time points.

RESULTS

Among the 30 eligible trials, 24 used CAE, 5 IT, and one CAE and IT. Multivariable meta-regression with duration of exercise training and percentage of males as independent variables and the change in VO2peak as a dependent variable showed that the change in VO2peak was negatively associated with duration of exercise training (coefficient=-0.061, p=0.027), implying the possible existence of a waning effect of exercise training on VO2peak in the long term. Multivariable meta-regression demonstrated that both age (coefficient=-0.140, p<0.001) and EF (coefficient=-0.149, p<0.001) could predict the change in VO2VT1, whereas only age (coefficient=-0.095, p=0.022), but not EF (coefficient = 0.082, p = 0.100), could predict the change in VO2peak. The posttraining peak respiratory exchange ratio, as an index of maximum effort during exercise testing, correlated positively with the change in VO2peak (coefficient=-0.021, p=0.044). The exercise-induced changes of VO2peak (p = 0.438) and VO2VT1 (p = 0.474) did not differ between CAE and IT groups.

CONCLUSIONS

Improvement of endurance capacity during cardiac rehabilitation may be detected more accurately with the assessment of VO2VT1 rather than VO2peak.

Exercise training outcomes in patients with chronic heart failure with reduced ejection fraction depend on patient background

Background

The aim of this study was to identify significant factors affecting the effectiveness of exercise training using information of the HF-ACTION (Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training) study.

Methods

Background factors influencing the effect of exercise training were comprehensively surveyed for 2,130 patients by multivariable Cox regression analysis with the stepwise variable selection, and only significant factors were selected that were statistically distinguished from dummy noise factors using the Boruta method.

Results

The analysis suggested that the use of beta-blockers, pulse pressure, hemoglobin level, electrocardiography findings, body mass index, and history of stroke at baseline potentially influenced the exercise effect on all-cause death (AD). Therefore, a hypothetical score to estimate the effect of exercise training was constructed based on the analysis. The analysis suggested that the score is useful in identifying patients for whom exercise training may be significantly effective in reducing all-caused death and hospitalization (ADH) as well as AD. Such a subpopulation accounted for approximately 40% of the overall study population. On the other hand, in approximately 45% of patients, the effect of exercise was unclear on either AD or ADH. In the remaining 15% of patients, it was estimated that the effect of exercise might be unclear for ADH and potentially rather increase AD.

Conclusions

This study is the first analysis to comprehensively evaluate the effects of various factors on the outcome of exercise training in chronic heart failure, underscoring the need to carefully consider the patient's background before recommending exercise training. However, it should be noted that exercise training can improve many outcomes in a wide variety of diseases. Therefore, given the limitations involved in post-hoc analyses of a single clinical trial, the characteristics of patients to whom the results of this analysis can be applied need attention, and also further research is necessary on the relationship between the degree of exercise and the outcomes. A new clinical trial would be needed to confirm the factors detected and the appropriateness of the score.

Clinical Predictors of Adherence to Exercise Training Among Individuals With Heart Failure: THE HF-ACTION STUDY

PURPOSE

Suboptimal adherence is a major limitation to achieving the benefits of exercise interventions, and our ability to predict and improve adherence is limited. The purpose of this analysis was to identify baseline clinical and demographic characteristics predicting exercise training adherence in the HF-ACTION study cohort.

METHODS

Adherence to exercise training, defined by the total duration of exercise performed (min/wk), was evaluated in 1159 participants randomized to the HF-ACTION exercise intervention. More than 50 clinical, demographic, and exercise testing variables were considered in developing a model of the min/wk end point for 1-3 mo (supervised training) and 10-12 mo (home-based training).

RESULTS

In the multivariable model for 1-3 mo, younger age, lower income, more severe mitral regurgitation, shorter 6-min walk test distance, lower exercise capacity, and Black or African American race were associated with poorer exercise intervention adherence. No variable accounted for >2% of the variance and the adjusted R2 for the final model was 0.14. Prediction of adherence was similarly limited for 10-12 mo.

CONCLUSIONS

Clinical and demographic variables available at the initiation of exercise training provide very limited information for identifying patients with heart failure who are at risk for poor adherence to exercise interventions.

Improving exercise capacity and quality of life using non-invasive heart failure treatments: evidence from clinical trials

Endpoints of large-scale trials in chronic heart failure have mostly been defined to evaluate treatments with regard to hospitalizations and mortality. However, patients with heart failure are also affected by very severe reductions in exercise capacity and quality of life. We aimed to evaluate the effects of heart failure treatments on these endpoints using available evidence from randomized trials. Interventions with evidence for improvements in exercise capacity include physical exercise, intravenous iron supplementation in patients with iron deficiency, and - with less certainty - testosterone in highly selected patients. Erythropoiesis-stimulating agents have been reported to improve exercise capacity in anaemic patients with heart failure. Sinus rhythm may have some advantage when compared with atrial fibrillation, particularly in patients undergoing pulmonary vein isolation. Studies assessing treatments for heart failure co-morbidities such as sleep-disordered breathing, diabetes mellitus, chronic kidney disease and depression have reported improvements of exercise capacity and quality of life; however, the available data are limited and not always consistent. The available evidence for positive effects of pharmacologic interventions using angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, beta-blockers, and mineralocorticoid receptor antagonists on exercise capacity and quality of life is limited. Studies with ivabradine and with sacubitril/valsartan suggest beneficial effects at improving quality of life; however, the evidence base is limited in particular for exercise capacity. The data for heart failure with preserved ejection fraction are even less positive, only sacubitril/valsartan and spironolactone have shown some effectiveness at improving quality of life. In conclusion, the evidence for state-of-the-art heart failure treatments with regard to exercise capacity and quality of life is limited and appears not robust enough to permit recommendations for heart failure. The treatment of co-morbidities may be important for these patient-related outcomes. Additional studies on functional capacity and quality of life in heart failure are required.

Effects of a Cardiac Rehabilitation Program Versus Usual Care on Cardiopulmonary Function in Patients With Cardiac Syndrome X

PURPOSE

Because of uncertainty in the pathophysiological process, the treatment of cardiac syndrome X (CSX) is still under study. Addressing the effects of cardiac rehabilitation (CR) can help promote the prescription of this modality as an adjuvant therapy for these patients.

METHODS

This study was performed on 30 patients with effort-induced angina pectoris using a positive exercise test and/or myocardial perfusion scan in the absence of obvious stenosis or a stenosis of <50% on coronary angiography. The patients were divided into the CR and usual care (UC) groups and underwent cardiopulmonary exercise testing with gas exchange analysis before and after the study. The Duke Treadmill Score was used to compare prognosis and survival estimates of patients.

RESULTS

An increase in peak oxygen uptake ((Equation is included in full-text article.)O2) was significantly higher in the CR group than in the control group (P = .017). Resting (Equation is included in full-text article.)O2 was also increased in the CR group, but its difference with the UC group was not statistically significant. Resting O2 pulse was increased in the CR group, which significantly differed between groups (P = .041). Exercise test duration and the Duke Treadmill Score significantly increased in the CR group as compared with the UC group (P = .003 and P = .002, respectively). Also, recovery heart rate in the first minute was significantly improved in CR group.

CONCLUSION

Adding a 4-wk course of CR to UC for patients with CSX not only increased the Duke Treadmill Score and exercise test duration but also improved the resting O2 pulse, peak (Equation is included in full-text article.)O2, and first-minute recovery heart rate.

Heterogeneity in the vasodilatory function of individual extremities

Objectives

Heterogeneity and homogeneity in the flow-mediated dilation of the human body's individual extremities are not fully understood, and the relationship between flow-mediated dilation and local muscle activity is unclear. We assessed the flow-mediated dilation of four individual extremities and sought to determine the contribution of local muscle activity (evaluated as muscle strength) to the flow-mediated dilation in each extremity.

Methods

Thirteen healthy young right-handed nonactive males participated. The flow-mediated dilation in the brachial and popliteal arteries at both arms and legs was assessed by ultrasound Doppler. Muscle strength was evaluated as the grip strength and knee extension.

Results

There was a significant difference in the brachial artery (BA)-FMD values between the subjects' dominant and non-dominant sides (8.0 ± 2.8 vs. 5.5 ± 2.2%, p < 0.05), whereas the two sides showed similar popliteal artery (PA)-FMD values. There was no significant correlation in flow-mediated dilation between the dominant brachial artery and popliteal artery. The BA-FMD was significantly correlated with the grip strength in both upper extremities (dominant: r = 0.562, non-dominant: r = 0.548; p < 0.05, respectively).

Conclusion

These results demonstrated heterogeneity in the flow-mediated dilation of individual extremities. We observed that local muscle activity can affect the local vascular function. Measurements of vasodilatory function in individual extremities should thus be carefully considered.

Peripheral muscle training with resistance exercise bands in patients with chronic heart failure. Long-term effects on walking distance and quality of life; a pilot study

Aims

This study aimed to describe a method of peripheral muscle training with resistance bands in patients with chronic heart failure (CHF) and to evaluate its effects on the 6 min walk test and quality of life up to 12 months using a home‐based programme.

Methods and results

Twenty‐two patients with stable CHF (19 men and 3 women), mean age 63.2 years (SD 8.1), New York Heart Association class II–III were randomized to individual home‐based training (HT group), or home‐based training with a group‐based start‐up in a hospital setting (GT group). A 6 min walk test, the Minnesota Living with Heart Failure Questionnaire (MLHFQ), and Short Form with 36 items (SF‐36) were administered at baseline and after 3, 6, 9, and 12 months. Exercise training resulted in statistically significant increased walking distance in both groups. The HT group increased on average 107 (80) m from baseline to 12 months, and the GT group by 100 (96) m. Health‐related quality of life, measured with MLHFQ and SF‐36, reached statistically significant improvements in both groups but at different time points. There were no statistically significant differences between groups on any parameters or follow‐ups.

Conclusions

Long‐term home‐based peripheral muscle training in patients with CHF, with or without an introductory period in a hospital setting, can be used for initial improvement and retention of walking distance and health‐related quality of life.

Collaborative care model improves self-care ability, quality of life and cardiac function of patients with chronic heart failure

Chronic heart failure (CHF) is a common chronic disease that requires much care. This study aimed to explore the effects of collaborative care model (CCM) on patients with CHF. A total of 114 CHF patients were enrolled in this study, and were randomly and equally divided into two groups: control and experimental. Patients in the two groups received either usual care or CCM for 3 continuous months. The impacts of CCM on the self-care ability and quality of life were assessed using self-care of heart failure index and short form health survey 12, respectively. Further, cardiac function was assessed by measuring left ventricular ejection fraction (LVEF) and the level of N-terminal pro-B-type natriuretic peptide (NT-proBNP), and by the 6-min walking test. Clinical and demographic characteristics of patients in the control and CCM groups were statistically equivalent. Compared with usual care, CCM significantly enhanced self-care abilities of patients with CHF, including self-care maintenance, self-care management and self-care confidence (all P<0.05). The physical and mental quality of life was also significantly improved by CCM (P<0.01 or P<0.05). Compared with usual care, CCM significantly increased the LVEF (P<0.01), decreased the NT-proBNP level (P<0.01), and enhanced exercise capacity (P<0.001). In conclusion, CCM improved the self-care, quality of life and cardiac function of patients with CHF compared with usual care.

Gender Differences in Patients with Heart Failure

Aim: The aim of this literature review was to review and discuss the differences between men and women with heart failure with regard to epidemiology, aetiology, diagnostics, prognosis, pharmacological and non-pharmacological treatment, and the impact of heart failure on psychosocial factors and healthcare utilisation. Method: Two primary health care resources, MEDLINE and CINAHL, were selected to review the current literature. In MEDLINE, 234 abstracts dealing with heart failure and gender/sex were found and in CINAHL, 20 abstracts. Conclusion: Men have a higher incidence of heart failure, but the overall prevalence rate is similar in both sexes, since women survive longer after the onset of heart failure. Women tend to be older when diagnosed with heart failure and more often have diastolic dysfunction than men. The extent of sex differences in treatment, hospital cost and quality of care can partly be explained by age differences. The life situations for men and women with heart failure are different. Physical and social restrictions affecting daily life activities are experienced as most bothersome for men, whereas restrictions affecting the possibility to support family and friends are most difficult to accept for women. Women with heart failure ascribe more positive meanings to their illness. Despite this, women seem to experience a lower overall quality of life than men. The known gender differences in patients with heart failure need to be highlighted in guidelines as well as implemented in standard care.

Effect of exercise training on respiratory muscle oxygenation in children with congenital heart disease

BACKGROUND

Diminished aerobic capacity and weakness of both respiratory and peripheral muscles have been observed in cardiac patients and may contribute to exercise limitation. The aim of this study was to evaluate the effects of a home-based training programme on aerobic fitness and oxygenation of the respiratory muscles in children with congenital heart disease (CHD).

METHODS AND RESULTS

Eighteen patients with CHD aged 12-15 years participated in this study. Ten patients (training group, TG) underwent a training programme for 12 weeks and eight patients served as a non-training control group (CG). All subjects performed a cardiopulmonary exercise test before and after the study period. Oxygenation of the respiratory muscles was assessed using near-infrared spectroscopy. No significant differences were observed, at baseline and after the completion of the study, between the CG and TG in peak exercise workload, oxygen uptake (VO2), carbon dioxide output (VCO2), pulmonary ventilation (VE), and heart rate (HR). However, a significant improvement in exercise performance was found in the TG versus the CG when results were compared at the ventilatory threshold (Vth): workload (45.2+/-8.0 versus 58.5+/-7.4%; P<0.05), VO2 (62.3+/-7.5 versus 69.8+/-5.1%; P<0.05), VCO2 (49.8+/-5.7 versus 60.0+/-5.8%; P<0.05), VE (42.8+/-9.9 versus 50.1+/-9.5%; P<0.05), and HR (69.5+/-6.1 versus 76.0+/-3.5%; P<0.05). After training, an improvement in oxygenation of the respiratory muscles was found in the TG from 60% of VO2max until the end of exercise. At the Vth, the TG showed greater oxygenation after training (55.1+/-6.6 versus 43.0+/-6.9%, P<0.01, respectively). Furthermore, we showed a significant correlation of the change in respiratory muscle oxygenation and VO2 in the TG (r=0.90, P<0.01).

CONCLUSION

It is concluded that general physical training at submaximal intensity induces better aerobic fitness and improves respiratory muscle oxygenation in children with CHD.

Factors and Interventions Influencing Health-Related Quality of Life in Patients with Heart Failure: A Review of the Literature

INTRODUCTION

Because of the lack of a cure for patients with chronic heart failure (HF), there has been a progressive interest in the use of health-related quality of life (Hr-QoL) as complementary end-point to mortality and morbidity.

AIM

The aim of this review was from a nursing perspective to describe Hr-QoL and the influencing factors of Hr-QoL, as well as to identify interventions aimed at influencing Hr-QoL in HF patients.

METHOD

Medline, Cinahl and PsycInfo databases were searched from 1995 to 2004. A total of 58 papers were included.

RESULTS

HF symptoms and activity status influence Hr-QoL negatively. However, several individual characteristics such as personality, gender and age must also be taken into consideration because different values might exist regarding what constitutes a good Hr-QoL. Nurse led interventions based on education, support and exercise can influence Hr-QoL positively. There is also a need of more studies about the effects of depression, sleep disturbances, support as well as education on Hr-QoL. There is also a need of exercise studies with larger sample sizes and older patients in higher NYHA classes.

CONCLUSION

Several individual factors impact Hr-QoL, therefore, must nursing interventions are individually adapted to the patient's resources.

Comparison of Different Forms of Exercise Training in Patients With Cardiac Disease: Where Does High-Intensity Interval Training Fit?

In this review, we discuss the most recent forms of exercise training available to patients with cardiac disease and their comparison or their combination (or both) during short- and long-term (phase II and III) cardiac rehabilitation programs. Exercise training modalities to be discussed include inspiratory muscle training (IMT), resistance training (RT), continuous aerobic exercise training (CAET), and high-intensity interval training (HIIT). Particular emphasis is placed on HIIT compared or combined (or both) with other forms such as CAET or RT. For example, IMT combined with CAET was shown to be superior to CAET alone for improving functional capacity, ventilatory function, and quality of life in patients with chronic heart failure. Similarly, RT combined with CAET was shown to optimize benefits with respect to functional capacity, muscle function, and quality of life. Furthermore, in recent years, HIIT has emerged as an alternative or complementary (or both) exercise modality to CAET, providing equivalent if not superior benefits to conventional continuous aerobic training with respect to aerobic fitness, cardiovascular function, quality of life, efficiency, safety, tolerance, and exercise adherence in both short- and long-term training studies. Finally, short-interval HIIT was shown to be useful in the initiation and improvement phases of cardiac rehabilitation, whereas moderate- or longer-interval (or both) HIIT protocols appear to be more appropriate for the improvement and maintenance phases because of their high physiological stimulus. We now propose progressive models of exercise training (phases II-III) for patients with cardiac disease, including a more appropriate application of HIIT based on the scientific literature in the context of a multimodal cardiac rehabilitation program.

Echo response and clinical outcome in CRT patients

Background

Change in left ventricular end-systolic volume (∆LVESV) is the most frequently used surrogate marker in measuring response to cardiac resynchronisation therapy (CRT). We investigated whether ∆LVESV is the best measure to discriminate between a favourable and unfavourable outcome and whether this is equally applicable to non-ischaemic and ischaemic cardiomyopathy.

Methods

205 CRT patients (age 65 ± 12 years, 69 % men) were included. At baseline and 6 months echocardiographic studies, exercise testing and laboratory measurements were performed. CRT response was assessed by: ∆LVESV, ∆LV ejection fraction (LVEF), ∆ interventricular mechanical delay, ∆VO₂ peak, ∆VE/VCO₂, ∆BNP, ∆creatinine, ∆NYHA, and ∆QRS. These were correlated to the occurrence of major adverse cardiac events (MACE) between 6 and 24 months.

Results

MACE occurred in 19 % of the patients (non-ischaemic: 13 %, ischaemic: 24 %). ∆LVESV remained the only surrogate marker for CRT response for the total population and patients with non-ischaemic cardiomyopathy, showing areas under the curve (AUC) of 0.69 and 0.850, respectively. For ischaemic cardiomyopathy, ∆BNP was the best surrogate marker showing an AUC of 0.66.

Conclusion

∆LVESV is an excellent surrogate marker measuring CRT response concerning long-term outcome for non-ischaemic cardiomyopathy. ∆LVESV is not suitable for ischaemic cardiomyopathy in which measuring CRT response remains difficult.

Fatiguing exercise initiated later in life reduces incidence of fibrillation and improves sleep quality in Drosophila

As the human body ages, the risk of heart disease and stroke greatly increases. While there is evidence that lifelong exercise is beneficial to the heart's health, the effects of beginning exercise later in life remain unclear. This study aimed to investigate whether exercise training started later in life is beneficial to cardiac aging in Drosophila. We examined 4-week-old wild-type virgin female flies that were exposed to exercise periods of either 1.5, 2.0, or 2.5 h per day, 5 days a week for 2 weeks. Using M-mode traces to analyze cardiac function by looking at parameters including heart rate, rhythmicity, systolic and diastolic diameter, and interval and fractional shortening, we found that cardiac function declined with age, shown by an increase in the number of fibrillation events and a decrease in fractional shortening. About 2.0 and 2.5 h of exercise per day displayed a reduced incidence of fibrillation events, and only physical exercise lasting 2.5-h period increased fractional shortening and total sleep time in Drosophila. These data suggested that training exercise needs to be performed for longer duration to exert physiological benefits for the aging heart. Additionally, climbing ability to assess the exercise-induced muscle fatigue was also measured. We found that 2.0 and 2.5 h of exercise caused exercise-induced fatigue, and fatiguing exercise is beneficial for cardiac and healthy aging overall. This study provides a basis for further study in humans on the impact of beginning an exercise regimen later in life on cardiac health.

Clinical usefulness of response profiles to rapidly incremental cardiopulmonary exercise testing

The advent of microprocessed "metabolic carts" and rapidly incremental protocols greatly expanded the clinical applications of cardiopulmonary exercise testing (CPET). The response normalcy to CPET is more commonly appreciated at discrete time points, for example, at the estimated lactate threshold and at peak exercise. Analysis of the response profiles of cardiopulmonary responses at submaximal exercise and recovery, however, might show abnormal physiologic functioning which would not be otherwise unraveled. Although this approach has long been advocated as a key element of the investigational strategy, it remains largely neglected in practice. The purpose of this paper, therefore, is to highlight the usefulness of selected submaximal metabolic, ventilatory, and cardiovascular variables in different clinical scenarios and patient populations. Special care is taken to physiologically justify their use to answer pertinent clinical questions and to the technical aspects that should be observed to improve responses' reproducibility and reliability. The most recent evidence in favor of (and against) these variables for diagnosis, impairment evaluation, and prognosis in systemic diseases is also critically discussed.

Life-long aerobic exercise preserved baseline cerebral blood flow but reduced vascular reactivity to CO2

PURPOSE

To examine the potential benefits of life-long aerobic exercise on brain health, in particular cerebrovascular function.

MATERIALS AND METHODS

Ten Masters athletes (MA) (seven males, three females; 74.5 ± 5.8 years) and 10 sedentary elderly individuals (SE) (eight males, two females; 75.4 ± 5.6 years) were recruited and baseline cerebral blood flow (CBF) and cerebral vascular reactivity (CVR) to CO2 were measured on a 3T MRI scanner. Nine sedentary young subjects were also recruited to serve as a control group to verify the age effect.

RESULTS

When compared to the SE group, MA showed higher CBF in posterior cingulate cortex/precuneus, which are key regions of the default-mode-network and are known to be highly sensitive to age and dementia. CVR in the MA brains were paradoxically lower than that in SE. This effect was present throughout the brain. Within the MA group, individuals with higher VO2max had an even lower CVR, suggesting a dose-response relationship.

CONCLUSION

Life-long aerobic exercise preserved blood supply in the brain's default-mode-network against age-related degradation. On the other hand, its impact on the cerebral vascular system seems to be characterized by a dampening of CO2 reactivity, possibly because of desensitization effects due to a higher lifetime exposure.

6-min walk test provides prognostic utility comparable to cardiopulmonary exercise testing in ambulatory outpatients with systolic heart failure

OBJECTIVES

The goal of this study was to compare the prognostic efficacy of the 6-min walk (6MW) and cardiopulmonary exercise (CPX) tests in stable outpatients with chronic heart failure (HF).

BACKGROUND

CPX and 6MW tests are commonly applied as prognostic gauges for systolic HF patients, but few direct comparisons have been conducted.

METHODS

Stable New York Heart Association (NYHA) functional class II and III systolic HF patients (ejection fraction ≤ 35%) from the HF-ACTION (Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training) trial were studied. 6MW distance (6MWD) and CPX indices (peak oxygen consumption [VO(2)] and ventilatory equivalents for exhaled carbon dioxide [VE/VCO(2)] slope) were compared as predictors of all-cause mortality/hospitalization and all-cause mortality over 2.5 years of mean follow-up.

RESULTS

A total of 2,054 HF-ACTION participants underwent both CPX and 6MW tests at baseline (median age 59 years; 71% male; 64% NYHA functional class II and 36% NYHA functional class III/IV). In unadjusted models and in models that included key clinical and demographic covariates, C-indices of 6MWD were 0.58 and 0.65 (unadjusted) and 0.62 and 0.72 (adjusted) in predicting all-cause mortality/hospitalization and all-cause mortality, respectively. C-indices for peak VO(2) were 0.61 and 0.68 (unadjusted) and 0.63 and 0.73 (adjusted). C-indices for VE/VCO(2) slope were 0.56 and 0.65 (unadjusted) and 0.61 and 0.71 (adjusted); combining peak VO(2) and VE/VCO(2) slope did not improve the C-indices. Overlapping 95% confidence intervals and modest integrated discrimination improvement values confirmed similar prognostic discrimination by 6MWD and CPX indices within adjusted models.

CONCLUSIONS

In systolic HF outpatients, 6MWD and CPX indices demonstrated similar utility as univariate predictors for all-cause hospitalization/mortality and all-cause mortality. However, 6MWD or CPX indices added only modest prognostic discrimination to models that included important demographic and clinical covariates.

A randomized study of the effects of exercise training on patients with atrial fibrillation

BACKGROUND

Exercise training is beneficial in ischemic and congestive heart disease. However, the effect on atrial fibrillation (AF) is unknown.

METHODS

Forty-nine patients with permanent AF (age [mean ± SD], 70.2 ± 7.8 years; male-to-female ratio, 0.75; body mass index [mean ± SD], 29.7 ± 4.3 kg/m(2)) were randomized to 12-week aerobic exercise training or a control group. Exercise capacity, 6-minute walk test (6MWT), cardiac output, quality of life, and natriuretic peptides were measured. Cardiac output was measured at rest and during ergometer testing, and atrial natriuretic peptide and N-terminal pro-B-type natriuretic peptide were measured before and after the training period. Quality of life was evaluated using the Short-Form 36 and Minnesota Living With Heart Failure (MLHF-Q) questionnaires.

RESULTS

Improved exercise capacity and 6MWT were observed in the active patients (P < .001), and at study end, there was a significant difference between the active patients and the controls (P = .002). Resting pulse decreased in the active patients (94.8 ± 22.4 to 86.3 ± 22.5 beats/min, P = .049) but remained unchanged in the controls. Cardiac output was unchanged from baseline to end-of-study period. The MLHF-Q score improved in the active group (21.1 ± 18.0 vs 15.4 ± 17.5, P = .03). Active patients showed progress in 3 of the 8 Short-Form 36 subscales: physical functioning (P = .02), general health perceptions (P = .001), and vitality (P = .02). Natriuretic peptides were unchanged.

CONCLUSION

Twelve weeks of exercise training increased exercise capacity and 6MWT and decreased resting pulse rate significantly in patients with AF. Overall quality of life increased significantly as measured by the cardiology-related MLHF-Q. Cardiac output and natriuretic peptides were unchanged in both groups.

Cardiac rehabilitation programs and health-related quality of life. State of the art

Cardiovascular disease is the main health problem in developed countries. Prevention is presented as the most effective and efficient primary care intervention, whereas cardiac rehabilitation programs are considered the most effective of secondary prevention interventions; however, these are underused. This literature review examines the effectiveness and the levels of evidence of cardiac rehabilitation programs, their components, their development and role in developed countries, applications in different fields of research and treatment, including their psychological aspects, and their application in heart failure as a paradigm of disease care under this type of intervention. It is completed by a review of the impact of such programs on measures of health-related quality of life, describing the instruments involved in studies in recent scientific literature.

The 6-min walk test: responses in healthy Canadians aged 45 to 85 years

We sought to describe responses to the 6-min walk test (6MWT) in healthy Canadian adults in order to facilitate interpretation of its results in patient populations. Seventy-seven healthy Canadians aged 45 to 85 years (65 ± 11 years, 40 females) completed this study. During a single visit, three 6MWTs were undertaken. The main outcome measure was 6-min walk distance (6MWD). Age, gender, height, and weight were recorded. In 61 (79%) participants, cardiorespiratory variables were collected during the third 6MWT using a calibrated portable gas analysis system. The 6MWD increased between the first and second test (615 ± 96 to 639 ± 98 m; p < 0.001) with no further improvement on the third test (638 ± 99 m; p = 0.945). The best 6MWD from the first 2 tests was 640 ± 99 m (range 416 to 880 m). A greater 6MWD was achieved by males compared with females (672 ± 94 vs. 611 ± 93 m; p = 0.005). The following equation accounted for 49% of the variance in 6MWD: 6MWD = 970.7 + (–5.5 × age) + (56.3 × gender), where females = 0, males = 1. The 6MWT elicited large cardiorespiratory responses with minimal symptoms. The rate of oxygen uptake measured at test-end was associated with the 6MWD (r = 0.802; p < 0.001). These data allow the 6MWD achieved in Canadian adults to be expressed as a percentage of the predicted value and provide researchers and clinicians with values for the expected cardiorespiratory responses in a healthy adult population for the purpose of comparison with patient populations.

The impact of training modalities on the clinical benefits of exercise intervention in patients with cardiovascular disease risk or type 2 diabetes mellitus

Exercise training intervention represents an effective means to reduce adipose tissue mass, improve glycaemic control and increase whole-body oxygen uptake capacity (VO(2peak)) in obesity, metabolic syndrome, type 2 diabetes mellitus (T2DM) and heart disease patients. In this manuscript, we review the impact of different exercise training modalities on clinical benefits of prolonged exercise intervention in these patient (sub)populations. By changing training modalities, significantly greater clinical benefits can be obtained. Greater training frequency and longer programme duration is associated with greater reduction in adipose tissue mass in obesity patients. A greater training frequency (up to 2 days/week) and a longer programme duration (up to 38 weeks) seems to be associated with greater improvements in VO(2peak) in heart disease patients. Longer programme duration and addition of resistance-type exercise further improve glycaemic control in T2DM patients. The first line of evidence seems to indicate that high-intensity interval exercise training has a greater impact on VO(2peak) in heart disease patients and insulin sensitivity in subjects with metabolic syndrome, but not on adipose tissue mass in obese subjects. However, it remains unclear whether addition of resistance-type exercise and continuous higher-intensity endurance-type exercise training are accompanied by greater improvements in VO(2peak) in heart disease patients. Furthermore, the impact of training session duration/volume on adipose tissue mass loss and glycaemic control in obesity and T2DM patients, respectively, is currently unknown. The impact of training frequency on glycaemic control remains to be investigated in T2DM patients.

Drosophila models of cardiac disease

The fruit fly Drosophila melanogaster has emerged as a useful model for cardiac diseases, both developmental abnormalities and adult functional impairment. Using the tools of both classical and molecular genetics, the study of the developing fly heart has been instrumental in identifying the major signaling events of cardiac field formation, cardiomyocyte specification, and the formation of the functioning heart tube. The larval stage of fly cardiac development has become an important model system for testing isolated preparations of living hearts for the effects of biological and pharmacological compounds on cardiac activity. Meanwhile, the recent development of effective techniques to study adult cardiac performance in the fly has opened new uses for the Drosophila model system. The fly system is now being used to study long-term alterations in adult performance caused by factors such as diet, exercise, and normal aging. The fly is a unique and valuable system for the study of such complex, long-term interactions, as it is the only invertebrate genetic model system with a working heart developmentally homologous to the vertebrate heart. Thus, the fly model combines the advantages of invertebrate genetics (such as large populations, facile molecular genetic techniques, and short lifespan) with physiological measurement techniques that allow meaningful comparisons with data from vertebrate model systems. As such, the fly model is well situated to make important contributions to the understanding of complicated interactions between environmental factors and genetics in the long-term regulation of cardiac performance.

Gender differences in satisfaction with life in patients with coronary heart disease: physical activity as a possible mediating factor

The objective of the present study was to examine if time varying, mediating effect of physical activity plays an important role in the gender-satisfaction with life relationship. Six hundred four male and 197 female patients were included. Principal outcomes of interest were self-report satisfaction with life and physical activity at baseline, 6, 12 and 24 months. The Krull and MacKinnon procedure for hierarchical linear modeling showed that the change in physical activity mediated the gender-satisfaction with life over a 2 year period. Results from the current study suggest that increased physical activity partially explains why males report having increased well-being than females after hospitalization. This suggests that future interventions need to focus on reducing the gender disparity in physical activity to improve differences noted in satisfaction with life. If higher physical activity levels impact satisfaction with life positively, the importance of physical activity for female patients is warranted.

Exercise training in older patients with heart failure and preserved ejection fraction: a randomized, controlled, single-blind trial

BACKGROUND

Heart failure (HF) with preserved left ventricular ejection fraction (HFPEF) is the most common form of HF in the older population. Exercise intolerance is the primary chronic symptom in patients with HFPEF and is a strong determinant of their reduced quality of life (QOL). Exercise training (ET) improves exercise intolerance and QOL in patients with HF with reduced ejection fraction (EF). However, the effect of ET in HFPEF has not been examined in a randomized controlled trial.

METHODS AND RESULTS

This 16-week investigation was a randomized, attention-controlled, single-blind study of medically supervised ET (3 days per week) on exercise intolerance and QOL in 53 elderly patients (mean age, 70±6 years; range, 60 to 82 years; women, 46) with isolated HFPEF (EF ≥50% and no significant coronary, valvular, or pulmonary disease). Attention controls received biweekly follow-up telephone calls. Forty-six patients completed the study (24 ET, 22 controls). Attendance at exercise sessions in the ET group was excellent (88%; range, 64% to 100%). There were no trial-related adverse events. The primary outcome of peak exercise oxygen uptake increased significantly in the ET group compared to the control group (13.8±2.5 to 16.1±2.6 mL/kg per minute [change, 2.3±2.2 mL/kg per minute] versus 12.8±2.6 to 12.5±3.4 mL/kg per minute [change, -0.3±2.1 mL/kg per minute]; P=0.0002). There were significant improvements in peak power output, exercise time, 6-minute walk distance, and ventilatory anaerobic threshold (all P<0.002). There was improvement in the physical QOL score (P=0.03) but not in the total score (P=0.11).

CONCLUSIONS

ET improves peak and submaximal exercise capacity in older patients with HFPEF.

Assessment of exercise capacity in African patients with chronic heart failure using six minutes walk test

BACKGROUND

The purpose of this study was to assess the functional capacity during a 6-minute corridor walk and a 6-minute bicycle ergometry exercise in patients with chronic heart failure (CHF).

METHOD

Thirty five patients with stable CHF were recruited for the study. Each subject performed six minutes corridor walk and 6-minute bicycle ergometry testing. The 6-minute walk required the subjects to walk at a self selected speed on a 20 meter marked level ground for 6-minute. All the subjects also performed a 6-minute exercise on a stationary bicycle ergometer with initial resistance of 20 watts and increased by 10 watts after 3-minutes. The perceived rate of exertion was assessed using a modified Borg Scale after each exercise mode. The maximum oxygen consumption was derived using American College of Sport Medicine equations.

RESULTS

Result showed high positive correlation between distance walked in the 6-minute and the maximum volume of oxygen (VO(2) max) (r = 0.65, P < 0.01). The average distance walked was 327 m +/- 12.03 m. The VO(2) max estimated during bicycle ergometry was higher (13.7 +/- 1.9 L) than during the six minutes walk (8.9 +/- 1.2 L).

CONCLUSION

Six minutes walk could be useful to evaluate exercise tolerance in patients with chronic heart failure, while the bicycle ergometer could be more appropriate in the assessment of maximum functional capacity in these patients.

A community model of group rehabilitation for older patients with chronic heart failure: A pilot study

PURPOSE

The aim of this study was to develop and evaluate a community-based programme for heart failure patients, with emphasis on exercise and education.

METHOD

In a before-and-after trial, subjects with heart failure underwent a 12-week group programme comprising of exercise, education and mutual support. Outcome measures included subjects' compliance and views of the programme, knowledge related to disease management, physical parameters (symptoms, exercise tolerance, muscle strength) and psychosocial well-being (using generic and disease-specific tools). A focus group was held and participants' feedback noted.

RESULTS

Overall patient compliance and satisfaction rate was high. Significant changes were observed in knowledge, physical performance and psychosocial parameters. Subjects' feedback following the programme was generally positive.

CONCLUSIONS

This pilot study shows that a group programme for heart failure patients is feasible, acceptable and improved physical status and quality of life. It can be a useful model in the management of chronic disease in the community.

Assessment of quality of life in severe heart failure

Improvement of health-related quality of life (HRQL) is increasingly recognized as a priority in the management of heart failure (HF). In this review, we highlight the dramatic improvement in HRQL often observed in patients with severe HF and give particular emphasis to the nonpharmacologic therapy of cardiac resynchronization therapy, left ventricular assist devices, and cardiac rehabilitation. We juxtapose this to the less consistent improvement in HRQL seen with interventions aimed at treatment of acute HF syndromes. Conflicting data wherein HRQL improves in parallel to a detrimental or neutral effect on cardiovascular morbidity and mortality are also presented. We conclude with future directions and make the case for HF-specific instruments intended for the assessment of HRQL in hospitalized patients, longitudinal studies in which HRQL is followed over time, and continued attention to the preferences of those with severe and acute HF.

Effects of a home-based exercise program on clinical outcomes in heart failure

BACKGROUND

The aim of this study was to determine the effects of a home-based exercise program on clinical outcomes. Exercise training improves exercise capacity in patients with heart failure (HF) but the long-term effects on clinical outcomes remain unknown.

METHODS

We randomized 173 patients with systolic HF to control (n = 87) or home-based exercise (n = 86). The primary end point was a composite of all-cause hospitalizations, emergency department admissions, urgent transplantation, and death at 12 months. Functional performance (as assessed by cardiopulmonary exercise testing and the 6-minute walk test), quality of life, and psychological states were measured at baseline, 3 months, and 6 months.

RESULTS

There was no significant difference between experimental and control groups in the combined clinical end point at 12 months and in functional status, quality of life, or psychological states over 6 months. Patients in the exercise group had a lower incidence of multiple (2 or more) hospitalizations compared with the control group: 12.8% versus 26.6%, respectively (P = .018).

CONCLUSIONS

A home-based walking program that incorporated aerobic and resistance exercise did not result in improved clinical outcomes at 1-year follow-up in this cohort of patients with systolic HF. However, the exercise program resulted in reduced rehospitalization rates.

Prevalence and management of chronotropic incompetence in heart failure

Although chronotropic incompetence (CI) has been shown to have important prognostic value in asymptomatic and coronary artery disease populations, much less attention has been given to the prevalence and impact of CI in heart failure. There is considerable variability in the reported prevalence of chronotropic impairment (25%-70%) in the heart failure literature, likely due to a lack of a standardized definition and/or differing assessment methodologies. Although the exact prevalence of CI is debatable and the precise pathophysiologic mechanisms involved remain uncertain, there is unambiguous evidence indicating that chronotropic impairment contributes significantly to the myriad of cardiovascular, neuromuscular, pulmonary, and neurohormonal maladaptations known to negatively impact the physical functional and quality of life of most heart failure patients. Specifically, an inappropriate chronotropic response to exercise can decrease peak exercise oxygen uptake by as much as 15% to 20%. Therapeutic interventions to improve chronotropic function, including endurance exercise training and rate-adaptive pacing, although promising, still warrant further investigation.

Effects of short-term exercise training on symptoms and quality of life in patients with chronic atrial fibrillation

BACKGROUND

A randomised study was conducted to determine if short-term exercise training in patients with chronic atrial fibrillation (AF) might improve symptoms and health-related quality of life (HRQoL).

METHODS

AF patients (64+/-7 years) were randomised to exercise training (n=15) or a 2-month control period (n=15) followed by an exercise training program (ETP). The ETP consisted of 24 training sessions with aerobic exercise and muscle strengthening. A cycle ergometer test, with recording of perceived exertion on the Borg scale, was performed. The participants completed HRQoL questionnaires, the Short-Form 36 (SF-36) and Symptom and Severity Checklist (SSCL), before and after training. Because there were no changes after two months in the control group, pooled data for all patients are presented before and after training.

RESULTS

Four of the eight SF-36 scales improved significantly (p<0.05) following training: physical functioning (82+/-14 pre-ETP, 86+/-10 post-ETP), bodily pain (82+/-17 pre-ETP, 92+/-14 post-ETP), vitality (61+/-14 pre-ETP, 68+/-13 post-ETP) and role-emotional (85+/-28 pre-ETP, 94+/-20 post-ETP). The SF-36 physical component summary scale also increased from 49+/-6 pre-ETP to 52+/-6 post-ETP (p<0.05). Significant improvements were also observed for summary and specific symptom scores of the SSCL. Exercise capacity improved by 41+/-20% and perceived exertion during testing by 1.4 points after training (p<0.05 for both).

CONCLUSIONS

The study demonstrates a significant improvement in HRQoL, symptoms during exercise testing and exercise capacity after a short-term exercise training program in patients with chronic AF.

Clinical evidence for a health benefit from cardiac rehabilitation: an update

The recent decision by the Centers for Medicare and Medicaid Services to expand the indications for cardiac rehabilitation (CR) provides an opportunity to review the clinical evidence of the efficacy of exercise in the CR setting for patients who have experienced an acute myocardial infarction, coronary artery bypass graft surgery, stable angina, percutaneous coronary intervention, chronic heart failure, cardiac transplant, or cardiac valve repair/replacement. Evidence shows that physician-directed, exercise-based CR positively affects the basic pathophysiology of coronary artery disease, the extent of disability and level of quality of life, and the ability to potentially impact events of both morbidity and mortality. The role of CR, including regular exercise, lifestyle modification, and appropriate medical therapy, is effective in younger and older men and women with cardiac diagnoses. The efficacy of this important therapeutic modality warrants its more widespread application.

Evidence for prescribing exercise as therapy in chronic disease

Considerable knowledge has accumulated in recent decades concerning the significance of physical activity in the treatment of a number of diseases, including diseases that do not primarily manifest as disorders of the locomotive apparatus. In this review we present the evidence for prescribing exercise therapy in the treatment of metabolic syndrome-related disorders (insulin resistance, type 2 diabetes, dyslipidemia, hypertension, obesity), heart and pulmonary diseases (chronic obstructive pulmonary disease, coronary heart disease, chronic heart failure, intermittent claudication), muscle, bone and joint diseases (osteoarthritis, rheumatoid arthritis, osteoporosis, fibromyalgia, chronic fatigue syndrome) and cancer, depression, asthma and type 1 diabetes. For each disease, we review the effect of exercise therapy on disease pathogenesis, on symptoms specific to the diagnosis, on physical fitness or strength and on quality of life. The possible mechanisms of action are briefly examined and the principles for prescribing exercise therapy are discussed, focusing on the type and amount of exercise and possible contraindications.

Home-based exercise improves functional performance and quality of life in women with diastolic heart failure

BACKGROUND

Diastolic heart failure (DHF) is common in older women. There have been no clinical trials that have identified therapies to improve symptoms in these patients. A total of 32 women with New York Heart Association class II and III DHF (left ventricular ejection fraction >45% and symptoms of dyspnea or fatigue) were randomized into a 12-week home-based, low-to-moderate intensity (40% and 60%, respectively) exercise and education program (intervention) or education only program (control). Methods and results The intervention group improved in the 6-minute walk test from 840 +/- 366 ft to 1043 +/- 317 ft versus 824 +/- 367 ft to 732 +/- 408 ft in the control group (P =.002). Quality of life also improved in the intervention group compared with the control group as measured by the Living with Heart Failure Questionnaire (41 +/- 26 to 24 +/- 18 vs 27 +/- 18 to 28 +/- 22 at 12 weeks, P =.002; 24 +/- 18 to 19 +/- 18 vs 28 +/- 22 to 32 +/- 27 at the 3-month follow-up, P =.014) and the Geriatric Depression Scale (6 +/- 4 to 4 +/- 4 vs 5 +/- 3 to 7 +/- 5 at 12 weeks, P =.012; 4 +/- 4 to 4 +/- 4 vs 7 +/- 5 to 7 +/- 5 at the 3-month follow-up, P =.009).

CONCLUSIONS

Women with DHF exhibit significant comorbidities and physical limitations. Home-based, low-to-moderate intensity exercise, in addition to education, is an effective strategy for improving the functional capacity and quality of life in women with DHF. Further study is needed to assess the long-term effect of exercise on clinical outcomes.

Effects of home-based exercise training on neurovascular control in patients with heart failure

BACKGROUND

The effect of home-based exercise training on neurovascular control in heart failure patients is unknown.

AIMS

To test the hypothesis that home-based training would maintain the reduction in muscle sympathetic nerve activity (MSNA) and forearm vascular resistance (FVR) acquired after supervised training.

METHODS AND RESULTS

Twenty-nine patients (54+/-1.9 years, EF<40%) were randomised into two groups: untrained control (n=12) and exercise trained (n=17). Both groups underwent assessment of Quality of Life (QoL), MSNA, and forearm blood flow. The exercise group underwent a 4-month supervised training program followed by 4 months of home-based training. After the initial 4 months of training, patients in the exercise group showed a significant increase in peak VO(2) and reduction in MSNA, compared to the untrained group, but this was not maintained during 4 months of home-based training. In contrast, the decrease in FVR (56+/-3 vs. 46+/-4 vs. 40+/-2 U, p=0.008) and the improvement in QOL that were achieved during supervised training were maintained during home-based training.

CONCLUSIONS

Home-based training following supervised training is a safe strategy to maintain improvements in QoL and reduction in FVR in chronic heart failure patients, but is an inadequate strategy to maintain fitness as estimated by peak VO(2) or reduction in neurohumoral activation.