Clinical Role of Exercise Training in the Management of Patients With Chronic Heart Failure

Effect of Mobile Internet Technology in Health Management of Heart Failure Patients Guiding Cardiac Rehabilitation

In this paper, we are going to explore the effect of mobile Internet technology in health management for the heart failure patients with cardiac rehabilitation. To implement and evaluate its effects in real environment, a total of 60 heart failure patients were divided, preferably in random fashion, into two groups of 30 cases, i.e., control and observation groups. The former group has received the routine home cardiac rehabilitation after discharge, and the latter group, i.e., observation, has received home cardiac rehabilitation based on mobile medical technical guidance after discharge. The 6 min walking test, Minnesota Cardiac Dysfunction Quality of Life Scale score, cardiac function index, and cardiac rehabilitation training compliance were matched between these groups specifically before and after the intervention. After 12 weeks of intervention, the 6 min walking test, Minnesota Cardiac Dysfunction Quality of Life Scale score, B-type natriuretic peptide of N-terminal, end-diastolic diameter preferably left ventricular, left ventricular ejection fraction, and compliance of training, specifically in the observation group, were better than the control group whereas statistically significant differences were observed, i.e., P < 0.01. Home cardiac rehabilitation guided by mobile Internet technology can improve the function of cardiac, exercise tolerance, life's quality, and compliance of patients with heart failure.

Post-translational modifications talk and crosstalk to class IIa histone deacetylases

Epigenetic modifications, such as histone or DNA modifications are key regulators of gene transcription and changes are often associated with maladaptive processes underlying cardiovascular disease. Epigenetic regulators therefore likely play a crucial role in cardiomyocyte homeostasis and facilitate the cellular adaption to various internal and external stimuli, responding to different intercellular and extracellular cues. Class IIa histone deacetylases are a class of epigenetic regulators that possess a myriad of post-transcriptional modification sites that modulate their activity in response to oxidative stress, altered catecholamine signalling or changes in the cellular metabolism. This review summaries the known reversible, post-translational modifications (PTMs) of class IIa histone deacetylases (HDACs) that ultimately drive transcriptional changes in homeostasis and disease. We also highlight the idea of a crosstalk of various PTMs on class IIa HDACs potentially leading to compensatory or synergistic effects on the class IIa HDAC-regulated cell behavior.

Prognostic impact of 6 min walk test distance in patients with systolic heart failure: insights from the WARCEF trial

AIMS

This study aimed to investigate the impact of baseline 6 min walk test distance (6MWTD) on time to major cardiovascular (CV) events in heart failure with reduced ejection fraction (HFrEF) and its impact in clinically relevant subgroups.

METHODS AND RESULTS

In the WARCEF (Warfarin versus Aspirin in Reduced Cardiac Ejection Fraction) trial, 6MWTD at baseline was available in 2102 HFrEF patients. Median follow-up was 3.4 years. All-cause death and heart failure hospitalization (HFH) exhibited a significant non-linear relationship with 6MWTD (P = 0.023 and 0.032, respectively), whereas a significant association between 6MWTD and CV death was shown in a linear model [hazard ratio (HR) per 10 m increase, 0.989; P = 0.011]. In linear splines with the best cut-off point at 200 m, the positive effect of a longer 6MWTD on all-cause death and HFH was only observed for 6MWTD > 200 m (HR per 10 m increase, 0.987; P = 0.0036 and 0.986; P = 0.0022, respectively). The associations between 6MWTD and CV outcomes were consistent across clinical subgroups; for age, a significant relationship between 6MWTD and HFH was observed in patients ≥60 years (HR per 10 m increase, 0.98; P < 0.001), but not in patients <60 years (HR per 10 m increase, 1.00; P = 0.98; P = 0.02 for the interaction).

CONCLUSIONS

In HFrEF, 6MWTD is independently associated with all-cause death, CV death, and HFH. 6MWTD of 200 m is the best cut-off point for predicting these adverse events. The prognostic impact of 6MWTD for HFH was only observed in older patients.

A network pharmacology approach to discover action mechanisms of Yangxinshi Tablet for improving energy metabolism in chronic ischemic heart failure

ETHNOPHARMACOLOGICAL RELEVANCE

Most cardiovascular diseases ultimately result in heart failure, an intractable problem in modern medicine. Yangxinshi tablet (YXS) is a Chinese medicine formula that is used clinically to treat coronary heart disease. However, the active compounds, potential targets, and pharmacological and molecular mechanism of its anti-heart failure activity remain unclear. Therefore, further investigation is required.

AIM OF STUDY

Active ingredients and potential targets of YXS for treating heart failure have been reported previously. However, the molecular functions or biological processes of YXS in energy metabolism have not been discovered. To date, no experimental study to validate the potential anti-heart failure mechanism of YXS. The aim of this study was to study the therapeutic effect of YXS on rats with chronic ischemic heart failure by evaluating rat cardiac function and exercise tolerance, and to explore its potential mechanism by network pharmacology, western blotting, quantitative RT-PCR and histological analysis.

MATERIALS AND METHODS

In this investigation, chronic ischemic heart failure rats were randomly assigned to five groups: control group (sham operation), model group (0.5% CMC-Na), trimetazidine group (positive control) and two YXS groups (low- and high-dose groups). Experimental rats were treated by gavage with 10 mg/kg/d (clinical equivalent dose) trimetazidine (TMZ), 500 mg/kg/d (clinical equivalent dose) YXS and 1000 mg/kg/d YXS, respectively, for 5 weeks. The cardiac functions of rats were detected by High-Resolution In Vivo Imaging System. We elucidated novel understanding of the active compounds of YXS in rat plasma and predicted the energy metabolism related targets and processes for heart failure. Then, we validated experimentally the targets and mechanism of YXS on these pathological processes in vivo.

RESULTS

It was found that YXS was able to effectively improve cardiac LVIDs, LVEDV, LVESV and EF, decrease myocardial oxygen consumption and reduce myocardial infarct size in rats with chronic ischemic heart failure was similar to that of TMZ. We identified 63 major candidate targets for YXS that are closely to heart failure progression. Enrichment analysis revealed key targets for YXS associated to oxygen delivery, glucose utilization, and mitochondrial biogenesis. Meanwhile, we validated that YXS could promote the expression of downstream HIF-1α, PGC1α and GLUT4 by increasing phosphorylation of PI3K, Akt, mTOR, rpS6 and AMPK. The results show that YXS could activate related PI3K/Akt/mTOR/rpS6/HIF-1α and AMPK/PGC1α/GLUT4 signaling pathways in chronic ischemic heart failure rats. Further experiments demonstrated that YXS increased mitochondrial biogenesis in chronic ischemic heart failure rats and improved exercise tolerance CONCLUSION: YXS treated chronic ischemic heart failure through activating its targets which play pivotal roles in oxygen delivery, glucose utilization and mitochondrial biogenesis to improve energy metabolism through a multi-component, multi-level, multi-target, multi-pathway and multi-mechanism approaches.

Prognostic Role of Left Ventricular Dysfunction in Patients With Coronary Artery Disease After an Ambulatory Cardiac Rehabilitation Program

The relationship between left ventricular ejection fraction (LVEF) and outcomes after cardiac rehabilitation (CR) is not well established; therefore we assessed the prognostic role of LVEF at the end of ambulatory CR program in patients (pts) who received coronary revascularization. LVEF was evaluated at hospital discharge and re-assessed at the end of CR in all ST-elevation myocardial infarction and coronary artery bypass graft pts, while in pts with non-ST-elevation MI or elective percutaneous coronary intervention the echocardiography was repeated if they had an impaired LVEF at discharge. New hospitalizations for cardiovascular causes at 1-year, and cardiovascular mortality during long-term follow-up were analyzed. We enrolled in CR 3078 pts, 86% showed LVEF ≥40% and 9% LVEF <40%. Of those with a discharge LVEF <40%, 56% improved LVEF (LVEF ≥40%) after CR. At 1-year, heart failure was the main cause of new hospitalizations in LVEF <40% group compared with LVEF ≥40% group (5% vs 0.4%, p <0.01). During a mean follow up of 48 ± 25 months, cardiovascular death occurred in 9% of pts with LVEF <40% and in 2% with LVEF ≥40% (p = 0.014). At Cox multivariate analysis, LVEF <40% at the end of CR and age were independent predictors of hospitalization and mortality for cardiovascular causes, while coronary artery bypass graft was a protective factor. In conclusion, during CR the improvement of LVEF occurs in a relevant proportion of patients, the re-assessment of LVEF at the end of the CR is helpful for risk stratification because left ventricle dysfunction at the end of CR is associated with worse cardiovascular outcomes.

Management of advanced heart failure: a review

INTRODUCTION

Heart failure (HF) has become a global pandemic. Despite recent developments in both medical and device treatments, HF incidences continues to increase. The current definition of HF restricts itself to stages at which clinical symptoms are apparent. In advanced heart failure (AdHF), it is universally accepted that all patients are refractory to traditional therapies. As the number of HF patients increase, so does the need for additional treatments, with an increased proportion of patients requiring advanced therapies. Areas covered: This review discusses extensive evidence for the effect of medical treatment on HF, although the data on the effect on AdHF is scare. Authors review the relevant literature for treating AdHF patients. Furthermore, mechanical circulatory devices (MCD) have emerged as an alternative to heart transplantation and have been shown to enhance quality of life and reduce mortality therefore authors also review the current literature on the different MCD and technologies. Expert commentary: More patients will need advanced therapies, as the access to heart transplantation is limited by the number of available donors. AdHF patients should be identified timely since the window of opportunities for advanced therapy is narrow as their morbidity is progressive and survival is often short.

Physical Therapy Self-Management Strategies for a Patient With a Total Hip Replacement and Heart Failure: A Case Report

Heart failure (HF) is the most common reason for admission to the hospital in people over the age of 65 and has been found to be a possible complication following a joint replacement. Self-management education has been shown to reduce hospital readmissions rates among patients with HF and to cause significant improvements. The purpose of this case report was to describe physical therapy (PT) self-management education in the care of a patient with both a recent hip replacement (THR) surgery and HF.

CASE DESCRIPTION

85-year-old female with a THR and HF. Objective measurements included Timed Up and Go Test (TUG); 10-meter walk test (10MWT) and the 6-minute walk test (6MWT). Standard PT care for THR and self-management education strategies was provided. The patient was seen two times per week for nine weeks. Improvements were noted in all outcome measures: (TUG, 10MWT, 6MWT). The patient was able to meet all ambulation goals and become independent in transfers. In this case, self-management education was shown to provide positive benefits by increasing functional mobility and helping prevent further complications from HF. Self- management education in the home health setting is important for older adult patients who had a THR.

Dose-Response Relationship Between Exercise Intensity, Mood States, and Quality of Life in Patients With Heart Failure

BACKGROUND

We conducted a secondary analysis to (1) compare changes in mood disorders and quality of life (QOL) among 4 groups of patients with heart failure in a home-based exercise program who had varying degrees of change in their exercise capacity and (2) determine whether there was an association between exercise capacity, mood disorders, and QOL.

METHODS

Seventy-one patients were divided into 4 groups based on changes in exercise capacity from baseline to 6 months: group 1showed improvements of greater than 10% (n = 19), group 2 showed improvements of 10% or less (n = 16), group 3 showed reductions of 10% or less (n = 9), and group 4 showed reductions of greater than 10% (n = 27).

RESULTS

Over time, patients in all 4 groups demonstrated significantly lower levels of depression and hostility (P < .001) and higher levels of physical and overall quality of life (P = .046). Group differences over time were noted in anxiety (P = .009), depression (P = .015), physical quality of life (P < .001), and overall quality of life (P = .002). Greater improvement in exercise capacity was strongly associated with lower depression scores (r = -0.49, P = .01).

CONCLUSIONS

An improvement in exercise capacity with exercise training was associated with a decrease in depression and anxiety and an increase in QOL in patients with heart failure.

Chronic interval exercise training prevents BKCa channel-mediated coronary vascular dysfunction in aortic-banded miniswine

Conventional treatments have failed to improve the prognosis of heart failure with preserved ejection fraction (HFpEF) patients. Thus, the purpose of this study was to determine the therapeutic efficacy of chronic interval exercise training (IT) on large-conductance Ca²⁺-activated K⁺ (BK_Ca) channel-mediated coronary vascular function in heart failure. We hypothesized that chronic interval exercise training would attenuate pressure overload-induced impairments to coronary BK_Ca channel-mediated function. A translational large-animal model with cardiac features of HFpEF was used to test this hypothesis. Specifically, male Yucatan miniswine were divided into three groups ( n = 7/group): control (CON), aortic banded (AB)-heart failure (HF), and AB-interval trained (HF-IT). Coronary blood flow, vascular conductance, and vasodilatory capacity were measured after administration of the BK_Ca channel agonist NS-1619 both in vivo and in vitro in the left anterior descending coronary artery and isolated coronary arterioles, respectively. Skeletal muscle citrate synthase activity was decreased and left ventricular brain natriuretic peptide levels increased in HF vs. CON and HF-IT animals. A parallel decrease in NS-1619-dependent coronary vasodilatory reserve in vivo and isolated coronary arteriole vasodilatory responsiveness in vitro were observed in HF animals compared with CON, which was prevented in the HF-IT group. Although exercise training prevented BK_Ca channel-mediated coronary vascular dysfunction, it did not change BK_Ca channel α-subunit mRNA, protein, or cellular location (i.e., membrane vs. cytoplasm). In conclusion, these results demonstrate the viability of chronic interval exercise training as a therapy for central and peripheral adaptations of experimental heart failure, including BK_Ca channel-mediated coronary vascular dysfunction. NEW & NOTEWORTHY Conventional treatments have failed to improve the prognosis of heart failure with preserved ejection fraction (HFpEF) patients. Our findings show that chronic interval exercise training can prevent BK_Ca channel-mediated coronary vascular dysfunction in a translational swine model of chronic pressure overload-induced heart failure with relevance to human HFpEF.

Chronic low-intensity exercise attenuates cardiomyocyte contractile dysfunction and impaired adrenergic responsiveness in aortic-banded mini-swine

Exercise improves clinical outcomes in patients diagnosed with heart failure with reduced ejection fraction (HFrEF), in part via beneficial effects on cardiomyocyte Ca²⁺ cycling during excitation-contraction coupling (ECC). However, limited data exist regarding the effects of exercise training on cardiomyocyte function in patients diagnosed with heart failure with preserved ejection fraction (HFpEF). The purpose of this study was to investigate cardiomyocyte Ca²⁺ handling and contractile function following chronic low-intensity exercise training in aortic-banded miniature swine and test the hypothesis that low-intensity exercise improves cardiomyocyte function in a large animal model of pressure overload. Animals were divided into control (CON), aortic-banded sedentary (AB), and aortic-banded low-intensity trained (AB-LIT) groups. Left ventricular cardiomyocytes were electrically stimulated (0.5 Hz) to assess Ca²⁺ homeostasis (fura-2-AM) and unloaded shortening during ECC under conditions of baseline pacing and pacing with adrenergic stimulation using dobutamine (1 μM). Cardiomyocytes in AB animals exhibited depressed Ca²⁺ transient amplitude and cardiomyocyte shortening vs. CON under both conditions. Exercise training attenuated AB-induced decreases in cardiomyocyte Ca²⁺ transient amplitude but did not prevent impaired shortening vs. CON. With dobutamine, AB-LIT exhibited both Ca²⁺ transient and shortening amplitude similar to CON. Adrenergic sensitivity, assessed as the time to maximum inotropic response following dobutamine treatment, was depressed in the AB group but normal in AB-LIT animals. Taken together, our data suggest exercise training is beneficial for cardiomyocyte function via the effects on Ca²⁺ homeostasis and adrenergic sensitivity in a large animal model of pressure overload-induced heart failure. NEW & NOTEWORTHY Conventional treatments have failed to improve the prognosis of heart failure with preserved ejection fraction (HFpEF) patients. Our findings show chronic low-intensity exercise training can prevent cardiomyocyte dysfunction and impaired adrenergic responsiveness in a translational large animal model of chronic pressure overload-induced heart failure with relevance to human HFpEF.

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.

Exercise Training in Group 2 Pulmonary Hypertension: Which Intensity and What Modality

Pulmonary hypertension (PH) due to left-sided heart disease (LSHD) is a common and disconcerting occurrence. For example, both heart failure (HF) with preserved and reduced ejection fraction (HFpEF and HFrEF) often lead to PH as a consequence of a chronic elevation in left atrial filling pressure. A wealth of literature demonstrates the value of exercise training (ET) in patients with LSHD, which is particularly robust in patients with HFrEF and growing in patients with HFpEF. While the effects of ET have not been specifically explored in the LSHD-PH phenotype (i.e., composite pathophysiologic characteristics of patients in this advanced disease state), the overall body of evidence supports clinical application in this subgroup. Moderate intensity aerobic ET significantly improves peak oxygen consumption, quality of life and prognosis in patients with HF. Resistance ET significantly improves muscle strength and endurance in patients with HF, which further enhance functional capacity. When warranted, inspiratory muscle training and neuromuscular electrical stimulation are becoming recognized as important components of a comprehensive rehabilitation program. This review will provide a detailed account of ET programing considerations in patients with LSHD with a particular focus on those concomitantly diagnosed with PH.

Heart Failure as a Newly Approved Diagnosis for Cardiac Rehabilitation: Challenges and Opportunities

Many see the broadened eligibility of cardiac rehabilitation (CR) to include heart failure with reduced ejection fraction (HFrEF) as a likely catalyst to high CR enrollment and improved care. However, such expectation contrasts with the reality that CR enrollment of eligible coronary heart disease patients has remained low for decades. In this review, entrenched obstacles impeding utilization of CR are considered, particularly in relation to potential HFrEF management. The strengths and limitations of the HF-ACTION (Heart Failure-A Controlled Trial Investigating Outcomes of Exercise Training) trial to advance precepts of CR are considered, as well as gaps that this trial failed to address, such as the utility of CR for patients with heart failure with preserved ejection fraction and the conundrum of poor patient adherence.

Improving functional capacity in heart failure: the need for a multifaceted approach

PURPOSE OF REVIEW

Functional capacity is a broad term that describes a person's ability to perform the daily activities that require physical exertion. Patients diagnosed with heart failure, regardless of cause, demonstrate a compromised functional capacity. The ability to perform aerobic activities is a central, but not complete, determinant of functional capacity. Muscular strength and endurance are other important elements of functional capacity. It is well established that patients with heart failure demonstrate attenuated muscular strength and endurance as a consequence of their disease process. Typically, a heart failure patient's ability to perform daily activities that are either aerobic or resistive in nature is compromised and contributes to the decline in functional capacity.

RECENT FINDINGS

There is an abundance of literature demonstrating that exercise training improves aerobic capacity and muscular strength and endurance in those with heart failure. These training benefits translate to an improvement in functional capacity and an enhanced ability to perform activities of daily living. There are several approaches to exercise training in the heart failure population, each of which has implications for the degree to which functional capacity can be improved.

SUMMARY

This review summarizes the current body of literature related to exercise training as a means of optimizing functional capacity in patients with heart failure.

Incorporating patients with chronic heart failure into outpatient cardiac rehabilitation: practical recommendations for exercise and self-care counseling-a clinical review

PURPOSE

A recent policy change from the Centers for Medicare and Medicaid Services includes coverage of cardiac rehabilitation (CR) for patients with chronic heart failure (CHF) with reduced ejection fraction. This article provides a framework by which CR programs can incorporate disease-specific services for patients with CHF who participate in CR.

DISCUSSION

Cardiac rehabilitation should include self-care counseling that targets improved education and skill development (eg, medication compliance, monitoring/management of body weight). Various tools are available for assessing exercise tolerance (eg, stress test with gas exchange and 6-minute walk), health-related quality of life, and other outcome-related parameters. Exercise should be prescribed in a manner that progressively increases intensity, duration, and frequency, to a volume of exercise equivalent to 3 to 7 metabolic equivalent task (MET)-hr per week. The benefits of exercise training are limited by patient adherence; therefore, CR providers need to identify the adherence challenges unique to each patient and address each accordingly. To optimize the referral of patients with CHF to CR, program staff should develop strategies to raise both health care provider and patient awareness about the benefits of CR, as well as work collaboratively to set up system-based approaches to CR referral.

CONCLUSIONS

The referral of patients with CHF to CR will increase in 2014 and beyond, due partly to a policy change from the Centers for Medicare and Medicaid Services that allows coverage for CR. These patients should be integrated into existing programs, with the intent of providing both standard CR services and CHF-specific education and disease management activities that target improved outcomes.

A randomised controlled study of the long-term effects of exercise training on mortality in elderly people: study protocol for the Generation 100 study

INTRODUCTION

Epidemiological studies suggest that exercise has a tremendous preventative effect on morbidity and premature death, but these findings need to be confirmed by randomised trials. Generation 100 is a randomised, controlled study where the primary aim is to evaluate the effects of 5 years of exercise training on mortality in an elderly population.

METHODS AND ANALYSIS

All men and women born in the years 1936-1942 (n=6966), who were residents of Trondheim, Norway, were invited to participate. Between August 2012 and June 2013, a total of 1567 individuals (790 women) were included and randomised to either 5 years of two weekly sessions of high-intensity training (10 min warm-up followed by 4×4 min intervals at ∼90% of peak heart rate) or, moderate-intensity training (50 min of continuous work at ∼70% of peak heart rate), or to a control group that followed physical activity advice according to national recommendations. Clinical examinations, physical tests and questionnaires will be administered to all participants at baseline, and after 1, 3 and 5 years. Participants will also be followed up by linking to health registries until year 2035.

ETHICS AND DISSEMINATION

The study has been conducted according to the SPIRIT statement. All participants signed a written consent form, and the study has been approved by the Regional Committee for Medical Research Ethics, Norway. Projects such as this are warranted in the literature, and we expect that data from this study will result in numerous papers published in world-leading clinical journals; we will also present the results at international and national conferences.

TRIAL REGISTRATION NUMBER

Clinicaltrials.gov NCT01666340.

The obesity paradox in chronic heart failure: what does it mean?

Heart failure (HF) is a growing health problem, at least in part due to the concurrent obesity epidemic plaguing developed countries. However, once a patient develops HF, an elevated BMI appears to confer a survival benefit--a phenomenon termed the "obesity paradox." The exact explanation for this paradox has been difficult to ascertain. Numerous plausible mechanisms have been asserted, including the fact that obese patients tend to be younger and more symptomatic, leading them to seek medical attention earlier in the course of their HF. Obese patients may also have larger energy reserves that help to offset the catabolic changes seen with HF. Other hypotheses highlight the limitations of BMI as an obesity classifier. The purpose of this review is to examine the various theories for the obesity paradox in HF and discuss the implications for the clinical management of obese patients with HF.

Provocative issues in heart disease prevention

In this article, new areas of cardiovascular (CV) prevention and rehabilitation research are discussed: high-intensity interval training (HIIT) and new concepts in nutrition. HIIT consists of brief periods of high-intensity exercise interspersed by periods of low-intensity exercise or rest. The optimal mode according our work (15-second exercise intervals at peak power with passive recovery intervals of the same duration) is associated with longer total exercise time, similar time spent near peak oxygen uptake (VO2 peak) VO2 peak, and lesser perceived exertion relative to other protocols that use longer intervals and active recovery periods. Evidence also suggests that compared with moderate-intensity continuous exercise training, HIIT has superior effects on cardiorespiratory function and on the attenuation of multiple cardiac and peripheral abnormalities. With respect to nutrition, a growing body of evidence suggests that the gut microbiota is influenced by lifestyle choices and might play a pivotal role in modulating CV disease development. For example, recent evidence linking processed (but not unprocessed) meats to increased CV risk pointed to the gut microbial metabolite trimethylamine N-oxide as a potential culprit. In addition, altered gut microbiota could also mediate the proinflammatory and cardiometabolic abnormalities associated with excess added free sugar consumption, and in particular high-fructose corn syrup. Substantially more research is required, however, to fully understand how and which alterations in gut flora can prevent or lead to CV disease and other chronic illnesses. We conclude with thoughts about the appropriate role for HIIT in CV training and future research in the role of gut flora-directed interventions in CV prevention.

Exercise physiology in heart failure and preserved ejection fraction

Recent advances in the pathophysiology of exercise intolerance in patients with heart failure with preserved ejection fraction (HFPEF) suggest that noncardiac peripheral factors contribute to the reduced peak V(o2) (peak exercise oxygen uptake) and to its improvement after endurance exercise training. A greater understanding of the peripheral skeletal muscle vascular adaptations that occur with physical conditioning may allow for tailored exercise rehabilitation programs. The identification of specific mechanisms that improve whole body and peripheral skeletal muscle oxygen uptake could establish potential therapeutic targets for medical therapies and a means to follow therapeutic response.

Exercise training in chronic heart failure

The syndrome of heart failure (HF) is a growing epidemic that causes a significant socio-economic burden. Despite considerable progress in the management of patients with HF, mortality and morbidity remain a major healthcare concern and frequent hospital admissions jeopardize daily life and social activities. Exercise training is an important adjunct nonpharmacological treatment modality for patients with HF that has proven positive effects on mortality, morbidity, exercise capacity and quality of life. Different training modalities are available to target the problems with which HF patients are faced. It is essential to tailor the prescribed exercise regimen, so that both efficiency and safety are guaranteed. Electrical implanted devices and mechanical support should not exclude patients from exercise training; however, particular precautions and a specialized approach are advised. At least 50% of patients with HF, older than 65 years of age, present with HF with preserved ejection fraction (HFPEF). Although the study populations included in studies evaluating the effect of exercise training in this population are small, the results are promising and seem to support the idea that exercise training is beneficial for HFPEF patients. Both the short- and especially long-term adherence to exercise training remain a major challenge that can only be tackled by a multidisciplinary approach. Efforts should be directed towards closing the gap between recommendations and the actual implementation of training programmes.

Heart failure with preserved ejection fraction: chronic low-intensity interval exercise training preserves myocardial O2 balance and diastolic function

We have previously reported chronic low-intensity interval exercise training attenuates fibrosis, impaired cardiac mitochondrial function, and coronary vascular dysfunction in miniature swine with left ventricular (LV) hypertrophy (Emter CA, Baines CP. Am J Physiol Heart Circ Physiol 299: H1348-H1356, 2010; Emter CA, et al. Am J Physiol Heart Circ Physiol 301: H1687-H1694, 2011). The purpose of this study was to test two hypotheses: 1) chronic low-intensity interval training preserves normal myocardial oxygen supply/demand balance; and 2) training-dependent attenuation of LV fibrotic remodeling improves diastolic function in aortic-banded sedentary, exercise-trained (HF-TR), and control sedentary male Yucatan miniature swine displaying symptoms of heart failure with preserved ejection fraction. Pressure-volume loops, coronary blood flow, and two-dimensional speckle tracking ultrasound were utilized in vivo under conditions of increasing peripheral mean arterial pressure and β-adrenergic stimulation 6 mo postsurgery to evaluate cardiac function. Normal diastolic function in HF-TR animals was characterized by prevention of increased time constant of isovolumic relaxation, normal LV untwisting rate, and enhanced apical circumferential and radial strain rate. Reduced fibrosis, normal matrix metalloproteinase-2 and tissue inhibitors of metalloproteinase-4 mRNA expression, and increased collagen III isoform mRNA levels (P < 0.05) accompanied improved diastolic function following chronic training. Exercise-dependent improvements in coronary blood flow for a given myocardial oxygen consumption (P < 0.05) and cardiac efficiency (stroke work to myocardial oxygen consumption, P < 0.05) were associated with preserved contractile reserve. LV hypertrophy in HF-TR animals was associated with increased activation of Akt and preservation of activated JNK/SAPK. In conclusion, chronic low-intensity interval exercise training attenuates diastolic impairment by promoting compliant extracellular matrix fibrotic components and preserving extracellular matrix regulatory mechanisms, preserves myocardial oxygen balance, and promotes a physiological molecular hypertrophic signaling phenotype in a large animal model resembling heart failure with preserved ejection fraction.

Expression of the irisin precursor FNDC5 in skeletal muscle correlates with aerobic exercise performance in patients with heart failure

BACKGROUND

Exercise-induced increase in peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) expression has been shown to increase the expression of the fibronectin type III domain containing 5 (FNDC5) gene and thereby its product, irisin, in mice. Given that exercise intolerance is a hallmark characteristic of heart failure (HF), and because PGC-1α and irisin promote exercise benefits in animals, we hypothesized that expression of these genes relates to aerobic performance in patients with HF.

METHODS AND RESULTS

Systolic HF (left ventricular ejection fraction ≤40%) patients underwent cardiopulmonary exercise testing to evaluate aerobic performance. High versus low aerobic performance was assessed using oxygen consumption (peak Vo(2) [>14 versus ≤14 mL O(2)·kg(-1)·min(-1)]) and ventilatory efficiency (VE/Vco(2) slope [<34 versus ≥34]). Muscle biopsies of the vastus lateralis and real-time polymerase chain reaction were used to quantify muscle gene expression. Twenty-four patients were studied. FNDC5 (5.7±3.5 versus 3.1±1.2, P<0.05) and PGC-1α (9.9±5.9 versus 4.5±1.9, P<0.01) gene expressions were greater in the high-peak Vo(2) group; correlation between FNDC5 and PGC-1α was significant (r=0.56, P<0.05) only in the high-peak Vo(2) group. Similarly, FNDC5 and PGC-1α gene expression was greater in the high-performance group based on lower VE/Vco(2) slopes (5.8±3.6 versus 3.3±1.4, P<0.05 and 9.7±6 versus 5.3±3.4, P<0.05); FNDC5 also correlated with PGC-1α (r=0.55, P<0.05) only in the low VE/Vco(2) slope group.

CONCLUSIONS

This is the first study to show that FNDC5 expression relates to functional capacity in a human HF population. Lower FNDC5 expression may underlie reduced aerobic performance in HF patients.

A combined aerobic and resistance exercise program improves physical functional performance in patients with heart failure: a pilot study

BACKGROUND

Recent guidelines for exercise in patients with heart failure (HF) recommended aerobic and resistance exercise as being safe and effective; however, the clinical and functional significance of these combined training modalities has not been established. In this pilot study, combined aerobic and resistance training was hypothesized to improve physical function, muscle strength, and health-related quality of life (HRQOL) compared with an attention control wait list (ACWL).

METHODS

The 10-item Continuous Scale Physical Functional Performance Test (CS-PFP10), which simulates common household chores; muscle strength (handgrip and knee extension); and HRQOL (Kansas City Cardiomyopathy Questionnaire) were evaluated at baseline (T1) and at 12 weeks (T2). The home-based moderate-intensity walking and resistance training program was performed 5 days a week.

RESULTS

Twenty-four New York Heart Association class II to III HF patients (mean [SD] age, 60 [10] years; mean [SD] left ventricular ejection fraction, 25% [9%]) were randomized to a combined aerobic and resistance exercise program or to an ACWL group. Of the total group, 58% were New York Heart Association class III HF patients, 50% were white, and 50% were female. The CS-PFP10 total scores were significantly increased in the exercise group, from 45 (18) to 56 (16). The Kansas City Cardiomyopathy Questionnaire overall summary score was significantly improved (P < .001) at T2 in the exercise intervention group compared with the ACWL group.

CONCLUSIONS

Participants provided the home-based, combined aerobic and resistance exercise program had significantly improved physical function, muscle strength, symptom severity, and HRQOL compared with the ACWL group. The findings of this study must be interpreted cautiously owing to the limitations of a small sample, data collection from a single center, and differences between control and interventions groups at baseline. A combined aerobic and resistance exercise approach may improve physical function in stable HF patients, but further study in a larger, more diverse population is recommended. However, in this study, the CS-PFP10 instrument demonstrated its ability to identify functional health status in HF patients and thus warrants further testing in a larger sample for possible use in clinical practice.

Adherence of heart failure patients to exercise: barriers and possible solutions: a position statement of the Study Group on Exercise Training in Heart Failure of the Heart Failure Association of the European Society of Cardiology

The practical management of heart failure remains a challenge. Not only are heart failure patients expected to adhere to a complicated pharmacological regimen, they are also asked to follow salt and fluid restriction, and to cope with various procedures and devices. Furthermore, physical training, whose benefits have been demonstrated, is highly recommended by the recent guidelines issued by the European Society of Cardiology, but it is still severely underutilized in this particular patient population. This position paper addresses the problem of non-adherence, currently recognized as a main obstacle to a wide implementation of physical training. Since the management of chronic heart failure and, even more, of training programmes is a multidisciplinary effort, the current manuscript intends to reach cardiologists, nurses, physiotherapists, as well as psychologists working in the field.

Selective repression of MEF2 activity by PKA-dependent proteolysis of HDAC4

Histone deacetylase 4 (HDAC4) regulates numerous gene expression programs through its signal-dependent repression of myocyte enhancer factor 2 (MEF2) and serum response factor (SRF) transcription factors. In cardiomyocytes, calcium/calmodulin-dependent protein kinase II (CaMKII) signaling promotes hypertrophy and pathological remodeling, at least in part by phosphorylating HDAC4, with consequent stimulation of MEF2 activity. In this paper, we describe a novel mechanism whereby protein kinase A (PKA) overcomes CaMKII-mediated activation of MEF2 by regulated proteolysis of HDAC4. PKA induces the generation of an N-terminal HDAC4 cleavage product (HDAC4-NT). HDAC4-NT selectively inhibits activity of MEF2 but not SRF, thereby antagonizing the prohypertrophic actions of CaMKII signaling without affecting cardiomyocyte survival. Thus, HDAC4 functions as a molecular nexus for the antagonistic actions of the CaMKII and PKA pathways. These findings have implications for understanding the molecular basis of cardioprotection and other cellular processes in which CaMKII and PKA exert opposing effects.

Effect of resistance training on physical disability in chronic heart failure

PURPOSE

Patients with chronic heart failure (CHF) report difficulty performing activities of daily living. To our knowledge, however, no study has directly measured performance in activities of daily living in these patients to systematically assess their level of physical disability. Moreover, the contribution of skeletal muscle weakness to physical disability in CHF remains unclear. Thus, we measured performance in activities of daily living in CHF patients and controls, its relationship to aerobic capacity and muscle strength, and the effect of resistance exercise training to improve muscle strength and physical disability.

METHODS

Patients and controls were assessed for performance in activities of daily living, self-reported physical function, peak aerobic capacity, body composition, and muscle strength before and after an 18-wk resistance training program. To remove the confounding effects of several disease-related factors (muscle disuse, hospitalization, acute illness), we recruited controls with similar activity levels as CHF patients and tested patients >6 months after any disease exacerbation/hospitalization.

RESULTS

Performance in activities of daily living was 30% lower (P < 0.05) in CHF patients versus controls and was related to both reduced aerobic capacity (P < 0.001) and muscle strength (P < 0.01). Moreover, resistance training improved (P < 0.05 to P < 0.001) physical function and muscle strength in patients and controls similarly, without altering aerobic capacity.

CONCLUSIONS

CHF patients are characterized by marked physical disability compared with age- and physical activity-matched controls, which is related to reduced aerobic capacity and muscle strength. CHF patients respond to resistance training with normal strength/functional adaptations. Our results support muscle weakness as a determinant of physical disability in CHF and show that interventions that increase muscle strength (resistance training) reduce physical disability.

Low-intensity interval exercise training attenuates coronary vascular dysfunction and preserves Ca²⁺-sensitive K⁺ current in miniature swine with LV hypertrophy

Coronary vascular dysfunction has been observed in several models of heart failure (HF). Recent evidence indicates that exercise training is beneficial for patients with HF, but the precise intensity and underlying mechanisms are unknown. Left ventricular (LV) hypertrophy can play a significant role in the development of HF; therefore, the purpose of this study was to assess the effects of low-intensity interval exercise training on coronary vascular function in sedentary (HF) and exercise trained (HF-TR) aortic-banded miniature swine displaying LV hypertrophy. Six months postsurgery, in vivo coronary vascular responses to endothelin-1 (ET-1) and adenosine were measured in the left anterior descending coronary artery. Baseline and maximal coronary vascular conductance were similar between all groups. ET-1-induced reductions in coronary vascular conductance (P < 0.05) were greater in HF vs. sedentary control and HF-TR groups. Pretreatment with the ET type A (ET(A)) receptor blocker BQ-123 prevented ET-1 hypersensitivity in HF animals. Whole cell voltage clamp was used to characterize composite K(+) currents (I(K(+))) in coronary smooth muscle cells. Raising internal Ca(2+) from 200 to 500 nM increased Ca(2+)-sensitive K(+) current in HF-TR and control, but not HF animals. In conclusion, an ET(A)-receptor-mediated hypersensitivity to ET-1, elevated resting LV wall tension, and decreased coronary smooth muscle cell Ca(2+)-sensitive I(K(+)) was found in sedentary animals with LV hypertrophy. Low-intensity interval exercise training preserved normal coronary vascular function and smooth muscle cell Ca(2+)-sensitive I(K(+)), illustrating a potential mechanism underlying coronary vascular dysfunction in a large-animal model of LV hypertrophy. Our results demonstrate the potential clinical impact of exercise on coronary vascular function in HF patients displaying pathological LV hypertrophy.

Cost-effectiveness of supervised exercise therapy in heart failure patients

OBJECTIVE

Exercise therapy in heart failure (HF) patients is considered safe and has demonstrated modest reduction in hospitalization rates and death in recent trials. Previous cost-effectiveness analysis described favorable results considering long-term supervised exercise intervention and significant effectiveness of exercise therapy; however, these evidences are now no longer supported. To evaluate the cost-effectiveness of supervised exercise therapy in HF patients under the perspective of the Brazilian Public Healthcare System.

METHODS

We developed a Markov model to evaluate the incremental cost-effectiveness ratio of supervised exercise therapy compared to standard treatment in patients with New York Heart Association HF class II and III. Effectiveness was evaluated in quality-adjusted life years in a 10-year time horizon. We searched PUBMED for published clinical trials to estimate effectiveness, mortality, hospitalization, and utilities data. Treatment costs were obtained from published cohort updated to 2008 values. Exercise therapy intervention costs were obtained from a rehabilitation center. Model robustness was assessed through Monte Carlo simulation and sensitivity analysis. Cost were expressed as international dollars, applying the purchasing-power-parity conversion rate.

RESULTS

Exercise therapy showed small reduction in hospitalization and mortality at a low cost, an incremental cost-effectiveness ratio of Int$26,462/quality-adjusted life year. Results were more sensitive to exercise therapy costs, standard treatment total costs, exercise therapy effectiveness, and medications costs. Considering a willingness-to-pay of Int$27,500, 55% of the trials fell below this value in the Monte Carlo simulation.

CONCLUSIONS

In a Brazilian scenario, exercise therapy shows reasonable cost-effectiveness ratio, despite current evidence of limited benefit of this intervention.

Exercise in elderly patients with chronic heart failure in primary care: effects on physical capacity and health-related quality of life

INTRODUCTION

Chronic heart failure (CHF) limits exercise capacity which influences physical fitness and health-related quality of life (HRQoL).

AIM

The aim was to determine the effects on physical capacity and HRQoL of an exercise programme in elderly patients with CHF in primary care.

METHODS

An exercise intervention was conducted as a prospective, longitudinal and controlled clinical study in primary care in elderly patients with CHF. Endurance exercise and resistance training were conducted as group-training at the primary care centre and as home training. Follow-up on physical capacity and HRQoL was done at 3, 6 and 12months.

RESULTS

Exercise significantly improved muscle endurance in the intervention group (n=29, mean age 76.2years) compared to the control group (n=31, mean age 74.4years) at all follow-ups except for shoulder flexion right at 12months (shoulder abduction p=0.006, p=0.048, p=0.029; shoulder flexion right p=0.002, p=0.032, p=0.585; shoulder flexion left p=0.000, p=0.046, p=0.004). Six minute walk test improved in the intervention group at 3months (p=0.013) compared to the control group. HRQoL measured by EQ5D-VAS significantly improved in the intervention group at 3 and 12months (p=0.016 and p=0.034) and SF-36, general health (p=0.048) and physical component scale (p=0.026) significantly improved at 3months compared to the control group.

CONCLUSION

This study shows that exercise conducted in groups in primary care and in the patients' homes could be used in elderly patients with CHF. The combination of endurance exercise and resistance training has positive effects on physical capacity. However, the minor effects in HRQoL need further verification in a study with a larger study population.

Effect of acute high-intensity interval exercise on postexercise biventricular function in mild heart failure

We studied the acute effect of high-intensity interval exercise on biventricular function using cardiac magnetic resonance imaging in nine patients [age: 49 ± 16 yr; left ventricular (LV) ejection fraction (EF): 35.8 ± 7.2%] with nonischemic mild heart failure (HF). We hypothesized that a significant impairment in the immediate postexercise end-systolic volume (ESV) and end-diastolic volume (EDV) would contribute to a reduction in EF. We found that immediately following acute high-intensity interval exercise, LV ESV decreased by 6% and LV systolic annular velocity increased by 21% (both P < 0.05). Thirty minutes following exercise (+30 min), there was an absolute increase in LV EF of 2.4% (P < 0.05). Measures of preload, left atrial volume and LV EDV, were reduced immediately following exercise. Similar responses were observed for right ventricular volumes. Early filling velocity, filling rate, and diastolic annular velocity remained unchanged, while LV untwisting rate increased 24% immediately following exercise (P < 0.05) and remained 18% above baseline at +30 min (P < 0.05). The major novel findings of this investigation are 1) that acute high-intensity interval exercise decreases the immediate postexercise LV ESV and increases LV EF at +30 min in patients with mild HF, and this is associated with a reduction in LV afterload and maintenance of contractility, and 2) that despite a reduction in left atrial volume and LV EDV immediately postexercise, diastolic function is preserved and may be modulated by enhanced LV peak untwisting rate. Acute high-intensity interval exercise does not impair postexercise biventricular function in patients with nonischemic mild HF.