Mechanisms of exercise training in patients with heart failure

Health-related quality of life in relation to different levels of disease severity in patients with chronic heart failure

The purpose of the present study was to compare differences in physiological outcomes and health-related quality of life (HRQOL) in relation to degree of illness in patients with chronic heart failure (CHF) and to compare HRQOL in CHF patients with that of a normal Japanese population. One hundred and twenty-five patients with stable CHF (93 men, 32 women, mean age 63.3 ± 12.4 years) with left ventricular ejection fraction (LVEF) of less than 40% were enrolled in the present study. We used New York Heart Association (NYHA) functional class as an index of degree of illness. In 64 of the 125 patients, physiological outcome measures included peak oxygen uptake (peak O2) and E/CO2 slope. HRQOL was assessed with the medical outcome study short form-36 (SF-36) Japanese version. In addition, SF-36 scores of CHF patients were compared against Japanese standard values. Age and LVEF did not differ according to NYHA functional class. The eight SF-36 subscale scores and peak O2 decreased with increases in the NYHA functional classes, whereas E/CO2 slope increased with increases in NYHA functional class (p<0.05). Of the 8 SF-36 subscales measured in CHF patients, only the bodily pain score attained that of the normal Japanese population. These findings suggest that HRQOL decreases as NYHA functional class increases and other physiological measures worsen. In addition, HRQOL values of CHF patients were low in comparison with standard values of a normal Japanese population.

Clinical utility of exercise training in heart failure with reduced and preserved ejection fraction

Reduced exercise tolerance is an independent predictor of hospital readmission and mortality in patients with heart failure (HF). Exercise training for HF patients is well established as an adjunct therapy, and there is sufficient evidence to support the favorable role of exercise training programs for HF patients over and above the optimal medical therapy. Some of the documented benefits include improved functional capacity, quality of life (QoL), fatigue, and dyspnea. Major trials to assess exercise training in HF have, however, focused on heart failure with reduced ejection fraction (HFREF). At least half of the patients presenting with HF have heart failure with preserved ejection fraction (HFPEF) and experience similar symptoms of exercise intolerance, dyspnea, and early fatigue, and similar mortality risk and rehospitalization rates. The role of exercise training in the management of HFPEF remains less clear. This article provides a brief overview of pathophysiology of reduced exercise tolerance in HFREF and heart failure with preserved ejection fraction (HFPEF), and summarizes the evidence and mechanisms by which exercise training can improve symptoms and HF. Clinical and practical aspects of exercise training prescription are also discussed.

Exercise training in adverse cardiac remodeling

Cardiac remodeling in response to a myocardial infarction or chronic pressure-overload is an independent risk factor for the development of heart failure. In contrast, cardiac remodeling produced by regular physical exercise is associated with a decreased risk for heart failure. There is evidence that exercise training has a beneficial effect on disease progression and survival in patients with cardiac remodeling and dysfunction, but concern has also been expressed that exercise training may aggravate pathological remodeling and dysfunction. Here we present studies from our laboratory into the effects of exercise training on pathological cardiac remodeling and dysfunction in mice. The results indicate that even in the presence of a large infarct, exercise training exerts beneficial effects on the heart. These effects were mimicked in part by endothelial nitric oxide synthase (eNOS) overexpression and abrogated by eNOS deficiency, demonstrating the importance of nitric oxide signaling in mediating the cardiac effects of exercise. Exercise prior to a myocardial infarction was also cardioprotective. In contrast, exercise tended to aggravate pathological cardiac remodeling and dysfunction in the setting of pressure-overload produced by an aortic stenosis. These observations emphasize the critical importance of the underlying pathological stimulus for cardiac hypertrophy and remodeling, in determining the effects of exercise training. Future studies are needed to define the influence of exercise type, intensity and duration in different models and severities of pathological cardiac remodeling. Together such studies will aid in optimizing the therapy of exercise training in the setting of cardiovascular disease.

Effect of home-based walking on performance and quality of life in patients with heart failure

INTRODUCTION

Chronic heart failure defined as the inability of the heart to meet the demands of the tissues, which results in symptoms of fatigue or dyspnoea on energy progressing to dyspnoea at rest. The inability to perform the exercise without discomfort and poor quality of life may be one of the first symptoms experienced by patients with heart failure and is often the principal reason for seeking medical care.

OBJECTIVES

The aim of the study was to find the effect of a home walking programme on the performance and quality of life in the patients with heart failure.

METHODS AND RESULTS

Sixty patients with New York Heart Association class II and III heart failure were divided into two matched and equal groups. The quality of life scores and 6-minute walking scores were measured for each patient at entry and after 8 weeks. Both groups were followed for 8 weeks. The results showed between mean walking distance on the 6 minutes at entry and after 8 weeks in the training group (p < 0.001), but no significance was seen between the control groups (p = 0.351). Furthermore, results showed a significant difference between mean of quality of life scores at entry and after 8 weeks in the training group, but such significance was not reported between before and after control group scores.

CONCLUSION

The home-based walking showed improvement in the performance, exercise tolerance time and quality of life in heart failure patients. Therefore, Nurses should employ alternatives such as home exercises in the caring of heart failure patients.

Effects of home-based exercise training for patients with chronic heart failure and sleep apnoea: a randomized comparison of two different programmes

Objective: To evaluate the effects of home-based exercise for patients with chronic heart failure and sleep apnoea and to compare two different training programmes.

Design: A randomized, prospective controlled trial.

Setting: Department of Cardiology, University Hospital, Brazil.

Subjects: Fifty chronic heart failure patients with sleep apnoea were randomized in three groups: Group 1 (aerobic training, n = 18), Group 2 (aerobic with strength training, n = 18), and Group 3 (untrained, n = 14).

Interventions: The training programme for Groups 1 and 2 began with three supervised exercise sessions, after they underwent three months of home-based exercise. Patients were followed by weekly telephone call and were reviewed monthly. Group 3 had the status of physical activity evaluated weekly by interview to make sure they remained untrained.

Main outcome measures: At baseline and after three months: cardiopulmonary exercise testing, isokinetic strength and endurance, Minnesota living with heart failure questionnaire and polysomnography. Adherence was evaluated weekly.

Results: Of the 50 patients enrolled in the study, 45 completed the programme. Clinical events: Group 1 (one death), Group 2 (one myocardial infarction), Group 3 (one death and two strokes). None were training related. Training groups showed improvement in all outcomes evaluated and the adherence was an important factor (Group 1 = 98.5% and Group 2 = 100.2%, P = 0.743). Untrained Group 3 demonstrated significant decrease or no change on measurements after three months without training.

Conclusion: Home-based exercise training is an important therapeutic strategy in chronic heart failure patients with sleep apnoea, and strength training resulted in a higher increase in muscle strength and endurance.

Current concepts underlying benefits of exercise training in congestive heart failure patients

The pathophysiology of several conditions including heart failure is partly attributable to a failure of the cell energy metabolism. Studies have shown that exercise training (ET) improves quality of life (QOL) and is beneficial in terms of reduction of symptoms, mortality and duration of hospitalization. Increasingly, ET is now achieving acceptance as complimentary therapy in addition to routine clinical practice in patients with chronic heart failure (CHF). However, the mechanisms underlying the beneficial effects of ET are far less understood and need further evaluation. Evidence suggests that while CHF induces generalized metabolic energy depletion, ET largely enhances the overall function of the heart muscle. Hence, research efforts are now aiming to uncover why ET is beneficial as a complimentary treatment of CHF in the context of improving endothelial function and coronary perfusion, decreasing peripheral resistance, induction of cardiac and skeletal muscle cells remodeling, increasing oxygen uptake, substrate oxidation, and resistance to fatigue. Here we discuss the current evidence that suggest that there are beneficial effects of ET on cardiac and skeletal muscle cells oxidative metabolism and intracellular energy transfer in patients with CHF.

AKT signalling in the failing heart

AKT is a serine/threonine protein kinase, also known as protein kinase B, which regulates cardiac growth, myocardial angiogenesis, glucose metabolism, and cell death in cardiac myocytes. AKT is activated by its phosphorylation at Thr 308 and ser 473 by PDK1 and mTORC2, respectively, in response to trophic stimuli such as insulin and insulin growth factor. c-Jun N-Terminal Kinases (JNKs) phosphorylate AKT at Thr 450 and potentiate its interaction with its downstream effectors. The short-term activation of AKT promotes physiological hypertrophy and protection from myocardial injury; whereas, its long-term activation causes pathological hypertrophy and heart failure. In this review we will discuss the role of AKT in regulating signalling pathways in the heart with special emphasis on the role of AKT in modulating stress induced autophagic cell death in cardiomyocytes in vitro.

Regulation of central angiotensin type 1 receptors and sympathetic outflow in heart failure

Angiotensin type 1 receptors (AT(1)Rs) play a critical role in a variety of physiological functions and pathophysiological states. They have been strongly implicated in the modulation of sympathetic outflow in the brain. An understanding of the mechanisms by which AT(1)Rs are regulated in a variety of disease states that are characterized by sympathoexcitation is pivotal in development of new strategies for the treatment of these disorders. This review concentrates on several aspects of AT(1)R regulation in the setting of chronic heart failure (CHF). There is now good evidence that AT(1)R expression in neurons is mediated by activation of the transcription factor activator protein 1 (AP-1). This transcription factor and its component proteins are upregulated in the rostral ventrolateral medulla of animals with CHF. Because the increase in AT(1)R expression and transcription factor activation can be blocked by the AT(1)R antagonist losartan, a positive feedback mechanism of AT(1)R expression in CHF is suggested. Oxidative stress has also been implicated in the regulation of receptor expression. Recent data suggest that the newly discovered catabolic enzyme angiotensin-converting enzyme 2 (ACE2) may play a role in the modulation of AT(1)R expression by altering the balance between the octapeptide ANG II and ANG- (1-7). Finally, exercise training reduces both central oxidative stress and AT(1)R expression in animals with CHF. These data strongly suggest that multiple central and peripheral influences dynamically alter AT(1)R expression in CHF.

Longitudinal cognitive performance in older adults with cardiovascular disease: evidence for improvement in heart failure

BACKGROUND

Cardiovascular disease (CVD) and particularly heart failure (HF) have been associated with cognitive impairment in cross-sectional studies, but it is unclear how cognitive impairment progresses over time in older adults with these conditions.

OBJECTIVE

The aim of this study was to prospectively examine cognitive function in patients with HF versus other forms of CVD.

METHOD

Seventy-five older adults (aged 53-84 years) with CVD underwent Doppler echocardiogram to evaluate cardiac status and 2 administrations of the Dementia Rating Scale (DRS), a test of global cognitive functioning, 12 months apart.

RESULTS

Although DRS performance did not statistically differ between groups at either administration, a significant between-group difference in the rate of cognitive change emerged (lambda = 0.87; F = 10.50; P = .002; omega 2 = 0.11). Follow-up analyses revealed that patients with HF improved significantly on global DRS performance, whereas patients with other forms of CVD remained stable. More specifically, patients with HF showed improvement on subscales of attention, initiation/perseveration, and conceptualization. Exploratory analyses indicated that higher diastolic blood pressure at baseline was associated with improved DRS performance in patients with HF (r = 0.38; P = .02).

CONCLUSIONS

Patients with HF exhibited modest cognitive improvements during 12 months, particularly in attention and executive functioning. Higher diastolic blood pressure at baseline was associated with improvement. These results suggest that cognitive impairment in patients with HF may be modifiable and that improved blood pressure control may be an important contributor to improved function. Further prospective studies are needed to replicate results and determine underlying mechanisms.

Physical training in patients with chronic heart failure of ischemic origin: effect on exercise capacity and left ventricular remodeling

BACKGROUND

Physical training is a well-known complementary treatment for chronic heart failure (CHF); however, many aspects require further studies. One of them is the impact on remodeling of the left ventricle (LV). The purpose of this study was to evaluate the effect of 6 months of training on LV, exercise capacity and safety issues in patients with ischemic CHF.

METHODS

Fifty patients (mean age 60.1+/-9.2 years) with ischemic CHF, New York Heart Association (NYHA) classification class II and III and left ventricular ejection fraction (LVEF) <or=35% were randomized into groups: undergoing 6-month training (25 patients) and not trained (25 patients). In both groups at baseline and at 6 months a cardiopulmonary exercise test and magnetic resonance imaging (MRI) with evaluation of LV were performed. Training was limited by the achievement of 80% of the predicted heart rate at VO2peak achieved at the baseline cardiopulmonary exercise test.

RESULTS

All patients completed the 6-month observation. No serious adverse events were found in either group. Exercise capacity improved only in the trained group (VO2peak increased by 31%). At 6 months in the trained group there was a tendency towards an improvement in some LV parameters: ejection fraction, end-diastolic volume and wall motion score index (WMSI), whereas an opposite trend was seen in the controls (P<0.05, P<0.05 and P<0.01 for comparison of LVEFs, end-diastolic volumes and WMSIs, respectively).

CONCLUSIONS

Six-month training in ischemic CHF patients is a safe modality. Training improves exercise capacity. There was no negative impact on LV morphology, and a trend towards improvement of functional parameters on MRI may suggest an anti-remodeling effect of training in patients with ischemic CHF.

Early exercise training normalizes myofilament function and attenuates left ventricular pump dysfunction in mice with a large myocardial infarction

The extent and mechanism of the cardiac benefit of early exercise training following myocardial infarction (MI) is incompletely understood, but may involve blunting of abnormalities in Ca(2+)-handling and myofilament function. Consequently, we investigated the effects of 8-weeks of voluntary exercise, started early after a large MI, on left ventricular (LV) remodeling and dysfunction in the mouse. Exercise had no effect on survival, MI size or LV dimensions, but improved LV fractional shortening from 8+/-1 to 12+/-1%, and LVdP/dt(P30) from 5295+/-207 to 5794+/-207 mm Hg/s (both P<0.05), and reduced pulmonary congestion. These global effects of exercise were associated with normalization of the MI-induced increase in myofilament Ca(2+)-sensitivity (DeltapCa(50)=0.037). This effect of exercise was PKA-mediated and likely because of improved beta(1)-adrenergic signaling, as suggested by the increased beta(1)-adrenoceptor protein (48%) and cAMP levels (36%; all P<0.05). Exercise prevented the MI-induced decreased maximum force generating capacity of skinned cardiomyocytes (F(max) increased from 14.3+/-0.7 to 18.3+/-0.8 kN/m(2) P<0.05), which was associated with enhanced shortening of unloaded intact cardiomyocytes (from 4.1+/-0.3 to 7.0+/-0.6%; P<0.05). Furthermore, exercise reduced diastolic Ca(2+)-concentrations (by approximately 30%, P<0.05) despite the unchanged SERCA2a and PLB expression and PLB phosphorylation status. Importantly, exercise had no effect on Ca(2+)-transient amplitude, indicating that the improved LV and cardiomyocyte shortening were principally because of improved myofilament function. In conclusion, early exercise in mice after a large MI has no effect on LV remodeling, but attenuates global LV dysfunction. The latter can be explained by the exercise-induced improvement of myofilament function.

Non-Pharmacological Interventions in Older People with Heart Failure: Effects of Exercise Training and Relaxation Therapy

BACKGROUND

Effective management of heart failure relies on optimal use of non-pharmacological therapy alongside medical treatment. Yet, there is an inadequate use of non-pharmacological therapy in caring for older people with heart failure.

OBJECTIVE

To examine the effects of relaxation therapy and exercise training on psychological outcomes and disease-specific quality of life of older heart failure patients.

METHODS

Subjects undertook relaxation (n = 59), exercise training (n = 32) or received attention placebo (n = 62) for 12 weeks. The relaxation group attended two training sessions, one revision workshop, and continued with twice-daily taped-directed home relaxation practice, with support from the intervener through bi-weekly telephone contact, for 12 weeks. The exercise group undertook 12 weekly sessions of resistance training and aerobic exercise and thrice weekly home exercise. The control group received regular telephone calls for general 'greetings'.

RESULTS

The relaxation and exercise groups reported a significantly greater improvement in psychological [F(2, 149) = 6.69, p = 0.002] and various disease-specific quality of life outcomes [dyspnea: F(2, 149) = 5.72, p = 0.004; fatigue: F(2, 149) = 3.78, p = 0.25; emotion: F(2, 149) = 6.68, p = 0.001], compared with those who received the attention placebo. While relaxation therapy was more effective to reduce psychological distress, with depression in particular (p < 0.001), exercise therapy worked better to control fatigue symptoms (p = 0.03).

CONCLUSION

Relaxation therapy and exercise training are effective to improve the psychological and physical health of older heart failure patients. They should be used as an individual treatment modality, or as care components of a disease management program.

Exercise capacity in apparently healthy survivors of cancer

AIMS

To evaluate cardiopulmonary exercise tolerance in a large cohort of apparently healthy paediatric cancer survivors in order to determine their participation in sporting activities.

METHODS

A total of 84 young (<21 years) asymptomatic childhood cancer survivors, who had been exposed to anthracyclines (mean dose 212 mg/m2) and/or chest irradiation (median dose 2000 cGy), with normal left ventricular systolic function at rest (fractional shortening >29%), and 79 healthy controls were studied. Exercise testing was performed on a treadmill ergometer. Gas exchange analysis and derived variables were measured on a breath-by-breath basis. Pulmonary functional evaluation was performed before exercise. Echocardiographic evaluation at rest was performed within one month before the exercise test.

RESULTS

There were no differences in exercise responses between patients and controls. In boys <13 years, mean VO2 max was slightly but significantly lower than in controls. This finding was thought to be a result of decreased physical fitness as all the other exercise parameters were similar to those in the controls.

CONCLUSIONS

Results show that apparently healthy survivors of paediatric cancer can take part in dynamic sporting activities if they exhibit a normal response to cardiopulmonary exercise testing, while those that exhibit a reduced VO2 max should be re-evaluated after an aerobic training programme, and should undergo tailored dynamic physical activity if the VO2 max does not normalise.

Lifestyle and dietary modification for prevention of heart failure

This article discusses the factors that contribute most to systolic and diastolic heart failure (HF): ischemic heart disease, hypertension,obesity, diabetes, and nephropathy. Diabetes often follows the insulin resistance syndrome in which obesity and hypertension are combined with dyslipidemia, and obesity is likely causal. Diabetes and hypertension are common causes of nephropathy, which in turn is a common precursor to HF. Insulin resistance, obesity,dyslipidemia, diabetes, and hypertension are risk factors for atherosclerotic coronary disease and left ventricular ischemia. Each is also a risk factor for diastolic dysfunction.

Improvement of alveolar-capillary membrane diffusing capacity with exercise training in chronic heart failure

Chronic heart failure (CHF) may impair lung gas diffusion, an effect that contributes to exercise limitation. We investigated whether diffusion improvement is a mechanism whereby physical training increases aerobic efficiency in CHF. Patients with CHF (n = 16) were trained (40 min of stationary cycling, 4 times/wk) for 8 wk; similar sedentary patients (n = 15) were used as controls. Training increased lung diffusion (DlCO, +25%), alveolar-capillary conductance (DM, +15%), pulmonary capillary blood volume (VC, +10%), peak exercise O2 uptake (peak VO2, +13%), and VO2 at anaerobic threshold (AT, +20%) and decreased the slope of exercise ventilation to CO2 output (VE/VCO2, -14%). It also improved the flow-mediated brachial artery dilation (BAD, from 4.8 +/- 0.4 to 8.2 +/- 0.4%). These changes were significant compared with baseline and controls. Hemodynamics were obtained in the last 10 patients in each group. Training did not affect hemodynamics at rest and enhanced the increase of cardiac output (+226 vs. +187%) and stroke volume (+59 vs. +49%) and the decrease of pulmonary arteriolar resistance (-28 vs. -13%) at peak exercise. Hemodynamics were unchanged in controls after 8 wk. Increases in DlCO and DM correlated with increases in peak VO2 (r = 0.58, P = 0.019 and r = 0.51, P = 0.04, respectively) and in BAD (r = 0.57, P < 0.021 and r = 0.50, P = 0.04, respectively). After detraining (8 wk), DlCO, DM, VC, peak VO2, VO2 at AT, VE/VCO2 slope, cardiac output, stroke volume, pulmonary arteriolar resistance at peak exercise, and BAD reverted to levels similar to baseline and to levels similar to controls. Results document, for the first time, that training improves DlCO in CHF, and this effect may contribute to enhancement of exercise performance.

Chronic Obstructive Pulmonary Disease and Chronic Heart Failure

Chronic obstructive pulmonary disease and congestive heart failure are two increasingly prevalent chronic diseases. Although care for these patients often is provided by different clinical teams, both disease conditions have much in common. In recent decades, more knowledge about the systemic impact of both diseases has become available, highlighting remarkable similarities in terms of prognostic factors and disease management. Rehabilitation programs deal with the systemic consequences of both diseases. Although clinical research also is conducted by various researchers investigating chronic obstructive pulmonary disease and chronic heart failure, it is worthwhile to compare the progress in relation to these two diseases over recent decades. Such comparison, the purpose of the current review, may help clinicians and scientists to learn about progress made in different, yet related, fields. The current review focuses on the similarities observed in the clinical impact of muscle weakness, the mechanisms of muscle dysfunction, the strategies to improve muscle function, and the effects of exercise training on chronic obstructive pulmonary disease and chronic heart failure.