Nonselective beta-adrenergic blockade with carvedilol does not hinder the benefits of exercise training in patients with congestive heart failure

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.

Effect of Early Rehabilitation on Physical Function in Patients Undergoing Coronary Artery Bypass Grafting: A Nationwide Inpatient Database Study

It is unclear when to begin rehabilitation after coronary artery bypass grafting (CABG) in the intensive care unit (ICU). Using the Japanese Diagnosis Procedure Combination inpatient database from 2010 to 2018, we identified adult patients who underwent a CABG and who were admitted to the ICU for ≥3 consecutive days from the date of their CABG. Patients who started any rehabilitation program prescribed by physicians or therapists within 3 days of CABG were defined as the early rehabilitation group, and the remaining patients were defined as the usual care group. We identified 30,568 eligible patients, with 13,150 (43%) patients in the early rehabilitation group. An inverse probability of treatment weighting analyses showed that the Barthel Index score at discharge in the early rehabilitation group was significantly higher than that in the usual care group (difference: 3.2; 95% confidence interval: 1.5–4.8). The early rehabilitation group had significantly lower in-hospital mortality, total hospitalization costs, length of ICU stay, and hospital stay vs. the usual care group. Our results suggested that early rehabilitation by physicians or therapists beginning within 3 days of CABG was safe, as suggested by the low mortality and improved physical function in patients who underwent CABG.

Exercise training improves cardiac function and attenuates arrhythmia in CPVT mice

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a lethal ventricular arrhythmia evoked by physical or emotional stress. Recessively inherited CPVT is caused by either missense or null-allele mutations in the cardiac calsequestrin (CASQ2) gene. It was suggested that defects in CASQ2 cause protein deficiency and impair Ca(2+) uptake to the sarcoplasmic reticulum and Ca(2+)-dependent inhibition of ryanodine channels, leading to diastolic Ca(2+) leak, after-depolarizations, and arrhythmia. To examine the effect of exercise training on left ventricular remodeling and arrhythmia, CASQ2 knockout (KO) mice and wild-type controls underwent echocardiography and heart rhythm telemetry before and after 6 wk of training by treadmill exercise. qRT-PCR and Western blotting were used to measure gene and protein expression. Left ventricular fractional shortening was impaired in KO (33 ± 5 vs. 51 ± 7% in controls, P < 0.05) and improved after training (43 ± 12 and 51 ± 9% in KO and control mice, respectively, P = nonsignificant). The exercise tolerance was low in KO mice (16 ± 1 vs. 29 ± 2 min in controls, P < 0.01), but improved in trained animals (26 ± 2 vs. 30 ± 3 min, P = nonsignificant). The hearts of KO mice had a higher basal expression of the brain natriuretic peptide gene. After training, the expression of natriuretic peptide genes markedly decreased, with no difference between KO and controls. Exercise training was not associated with a change in ventricular tachycardia prevalence, but appeared to reduce arrhythmia load, as manifested by a decrease in ventricular beats during stress. We conclude that, in KO mice, which recapitulate the phenotype of human CPVT2, exercise training is well tolerated and could offer a strategy for heart conditioning against stress-induced arrhythmia.

Effects of exercise training in patients with chronic heart failure and advanced left ventricular systolic dysfunction receiving β-blockers

BACKGROUND

It remains unclear whether patients with chronic heart failure (CHF) and advanced left ventricular (LV) dysfunction on β-blocker therapy benefit from exercise training (ET).

METHODS AND RESULTS

We studied 45 CHF patients with advanced LV dysfunction [ejection fraction (LVEF) < 25%] and impaired exercise tolerance [normalized peak oxygen uptake (PVO₂) < 70%] receiving a β-blocker: 33 patients participated in a cardiac rehabilitation program with ET (ET group) and 12 did not (inactive control group). Exercise capacity, LV dimension and plasma B-type natriuretic peptide (BNP) were assessed before and after a 3-month study period. At baseline, both groups had markedly reduced LVEF (ET group 18 ± 4% vs. Control group 18 ± 5%, NS) and impaired exercise capacity (normalized PVO₂ 51 ± 10% vs. 55 ± 9%, NS). Although one patient in the ET group withdrew from the program due to worsening CHF, no serious cardiac events occurred during the ET sessions. After 3 months, the ET group (n = 24) had significantly improved PVO₂ by 16 ± 15% (1,005 ± 295 to 1,167 ± 397ml/min, P < 0.001), while the PVO₂ of the control group was unchanged. LV end-diastolic dimension decreased in both groups to a similar extent, but plasma BNP was significantly decreased only in the ET group (432 to 214 pg/ml, P < 0.05).

CONCLUSIONS

The data indicate that in CHF patients with advanced LV dysfunction on β-blocker therapy, ET successfully improves exercise capacity and BNP without adversely affecting LV remodeling or causing serious cardiac complications.

Clinical utility of exercise training in chronic systolic heart failure

The volume of literature attesting to the clinical benefits of exercise training in patients with stable chronic heart failure (CHF) is substantial. Training can improve symptoms and exercise capacity, as well as reducing morbidity, mortality, and rates of emergency hospitalization. These benefits are apparent in all patients with stable CHF, irrespective of age or sex, or the etiology or severity of heart failure. Training regimens for patients with stable, systolic CHF should form part of a comprehensive heart-failure support effort and are best delivered using supervised in-hospital exercise combined with some training at home or in a group setting in community centers. In this Review, the modes and intensity of exercise training, selection of patients, duration of training effects, and other clinical guidance for using this treatment option are discussed.

[Physical training with beta-blockers in chronic heart failure]

In patients with chronic heart failure, the efficacy of beta-blocker therapy on mortality and the multiple benefits observed with physical training justify the association of the both. The effects of betablockade on different systems solicited in the exercise, particularly on the cardiocirculatory response during exercise test, rise many questions about the impact of beta blocker treatment on the changes induced by physical training. The cardioselective and vasodilating properties of beta-blockers play a role. It seems that the improved performance assessed by peak oxygen uptake (peak VO2) resulting from physical training is not limited by the beta-blocker treatment in patients with chronic heart failure. Synergistic effects have been observed, but many issues remain unsolved.

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.

Coexistent chronic obstructive pulmonary disease and heart failure in the elderly

The prevalence of chronic obstructive pulmonary disease (COPD) and chronic heart failure (CHF) increases substantially with age. The coexistence of COPD and CHF is common but often unrecognized in elderly patients. To avoid overlooking COPD in elderly patients with known CHF pulmonary function tests should be routinely obtained. Likewise, to avoid overlooking CHF in elderly patients with known COPD left ventricular (LV) function should be routinely assessed. Plasma brain natriuretic peptide levels are useful to differentiate COPD exacerbation from CHF decompensation in patients presenting with acute dyspnea. Aging exacerbates skeletal muscle alterations that occur in patients with CHF and COPD. Skeletal muscle metabolic alterations and atrophy and the resulting deterioration of functional capacity progress rapidly in elderly patients with COPD and CHF. Physical conditioning reverses rapidly progressing skeletal muscle metabolic alterations and atrophy and promotes independence and life quality in the elderly. Physical conditioning is clearly an essential component of the management of elderly patients with COPD and CHF. The pharmacological management of patients with coexistent COPD and CHF should focus on not depriving these patients from long-term beta adrenergic blockade. Long-term beta adrenergic blockade has been repeatedly shown to improve survival in elderly patients with CHF due to LV systolic dysfunction and, contrary to conventional belief, is well tolerated by patients with COPD.

Exercise training enhances baroreflex sensitivity by an angiotensin II-dependent mechanism in chronic heart failure

Exercise training (EX) has become an important modality capable of enhancing the quality of life and survival of patients with chronic heart failure (CHF). Although 4 wk of EX in animals with CHF evoked a reduction in renal sympathetic nerve activity and ANG II plasma levels and an enhancement in baroreflex sensitivity at rest (Liu JL, Irvine S, Reid IA, Patel KP, Zucker IH, Circulation 102: 1854-1862, 2000; Liu JL, Kulakofsky J, Zucker IH, J Appl Physiol 92: 2403-2408, 2002), it is unclear whether these phenomena are causally related. CHF was induced in rabbits by ventricular pacing (360-380 beats/min) for 3 wk. CHF rabbits were EX for 4 wk at 15-18 m/min, 6 days/wk, 30-40 min/day. Three groups of rabbits were studied: CHF (with no EX), CHF-EX, and CHF-EX + ANG II infusion [in which ANG II levels were kept at or near levels observed in CHF (non-EX) rabbits by subcutaneous osmotic minipump infusion]. EX prevented the increase in plasma ANG II levels shown in CHF rabbits. CHF and CHF-EX + ANG II infusion rabbits had significantly depressed baroreflex sensitivity slopes (P < 0.01 for sodium nitroprusside and P < 0.001 for phenylephrine) and higher baseline renal sympathetic nerve activities than CHF-EX animals. EX downregulated mRNA and protein expression of ANG II type 1 receptors in the rostral ventrolateral medulla in CHF rabbits. This was prevented by ANG II infusion. These data are consistent with the view that the reduction in sympathetic nerve activity and the improvement in baroreflex function in CHF after EX are due to the concomitant reduction in ANG II and angiotensin receptors in the central nervous system.

Exercise training and β-blocker treatment ameliorate age-dependent impairment of β-adrenergic receptor signaling and enhance cardiac responsiveness to adrenergic stimulation

Cardiac β-adrenergic receptor (β-AR) signaling and left ventricular (LV) responses to β-AR stimulation are impaired with aging. It is shown that exercise and β-AR blockade have a favorable effect on cardiac and vascular β-AR signaling in several cardiovascular diseases. In the present study, we examined the effects of these two different strategies on β-AR dysregulation and LV inotropic reserve in the aging heart. Forty male Wistar-Kyoto aged rats were randomized to sedentary, exercise (12 wk treadmill training), metoprolol (250 mg·kg−1·day−1 for 4 wk), and exercise plus metoprolol treatment protocols. Ten male Wistar-Kyoto sedentary young rats were also used as a control group. Old trained, old metoprolol-treated, and old trained plus metoprolol-treated rats showed significantly improved LV maximal and minimal first derivative of the pressure rise responses to β-AR stimulation (isoproterenol) compared with old untrained animals. We found a significant reduction in cardiac sarcolemmal membrane β-AR density and adenylyl cyclase activity in old untrained animals compared with young controls. Exercise training and metoprolol, alone or combined, restored cardiac β-AR density and G-protein-dependent adenylyl cyclase activation in old rats. Although cardiac membrane G-protein-receptor kinase 2 levels were not upregulated in untrained old compared with young control rats, both exercise and metoprolol treatment resulted in a dramatic reduction of G-protein-receptor kinase 2 protein levels, which is a further indication of β-AR signaling amelioration in the aged heart induced by these treatment modalities. In conclusion, we demonstrate for the first time that exercise and β-AR blockade can similarly ameliorate β-AR signaling in the aged heart, leading to improved β-AR responsiveness and corresponding LV inotropic reserve.

Exercise training reduces sympathetic nerve activity in heart failure patients treated with carvedilol

BACKGROUND

Evidence suggests that carvedilol decreases muscle sympathetic nerve activity (MSNA) in patients with heart failure (HF) but carvedilol fails to improve forearm vascular resistance and overall functional capacity. Exercise training in HF reduces MSNA and improves forearm vascular resistance and functional capacity.

AIMS

To investigate whether the beneficial effects exercise training on MSNA are maintained in the presence of carvedilol.

METHODS AND RESULTS

Twenty seven HF patients, NYHA Class II-III, EF <35%, peak VO(2) <20 ml/kg/min, treated with carvedilol were randomly divided into two groups: exercise training (n=15) and untrained (n=12). MSNA was recorded by microneurography. Forearm blood flow (FBF) was measured by venous occlusion plethysmography. The four-month training program consisted of three 60-min exercise/week on a cycloergometer. Baseline parameters were similar between groups. Exercise training reduced MSNA (-14+/-3.3 bursts/100 HB, p=0.001) and increased forearm blood flow (0.6+/-0.1 mL/min/100 g, p<0.001) in HF patients on carvedilol. In addition, exercise training improved peak VO(2) in HF patients (20+/-6%, p=0.002). MSNA, FBF and peak VO(2) were unchanged in untrained HF patients on carvedilol.

CONCLUSION

Exercise training reduces MSNA in heart failure patients treated with carvedilol. In addition, the beneficial effects of exercise training on muscle blood flow and functional capacity are still realized in patients on carvedilol.

Exercise testing with concurrent beta-blocker usage: is it useful? What do we learn?

Cardiopulmonary exercise testing (CPET) has been used for the assessment of severity of heart failure (HF), secondary to left ventricular systolic dysfunction. Initial studies determined that oxygen consumption (VO2) during exercise, as a measure of functional capacity, correlated well with the hemodynamic responses related to chronic HF. These studies led to the use of peak VO2 as a prognostic indicator in chronic HF. In addition, the use of several ventilatory parameters, eg, minute ventilation/carbon dioxide production during submaximal and peak exercise, were shown to have additive and (in some studies) superior prognostic value in patients with chronic HF. However, most of these studies were performed before beta-adrenergic blockade became the main focus of therapy in chronic HF. Unlike other drugs used in the treatment of HF, these drugs do not consistently improve exercise capacity as measured by peak VO2. Several retrospective studies and one prospective study have examined the effect of long-term beta-blocker therapy on the prognostic value of CPET in patients with chronic HF. These studies indicate that patients on beta-blockers have improved overall cardiovascular outcomes compared with patients not on these drugs. In addition, peak exercise VO2 still has prognostic value in beta-blocked patients; however, the thresholds for increased risk and need for transplantation have to be lower than in patients not on these drugs. There appears to be a real demand for a comprehensive survival score tool that includes the use of beta-blockade, along with CPET performance.

The role of exercise therapy in the treatment of patients with systolic heart failure

The predominant benefits of exercise training in systolic heart failure have been seen with aerobic training, although some information exists for the beneficial effects of resistive training as well. Although men clearly benefit from exercise training, the effects of exercise in women are less clear. Most of the studies have used supervised training 3 to 5 days a week for 8 weeks to 6 months, with 30 to 60 minutes of exercise per session. However, home exercise has been reported in a few studies, and appears to be safe and possibly efficacious. The effects of training on mortality are unknown at this time, although no study has demonstrated increased adverse events associated with training. Exercise training should be recommended for patients with stable New York Heart Association class II to III heart failure.

Angiotensin II--nitric oxide interactions in the control of sympathetic outflow in heart failure

Activation of the sympathetic nervous system is a compensatory mechanism which initially provides support for the circulation in the face of a falling cardiac output. It has been recognized for some time that chronic elevation of sympathetic outflow with the consequent increase in plasma norepinephrine, is counterproductive to improving cardiac function. Indeed, therapeutic targeting to block excessive sympathetic activation in heart failure is becoming a more accepted modality. The mechanism(s) by which sympathetic excitation occurs in the heart failure state are not completely understood. Components of abnormal cardiovascular reflex regulation most likely contribute to this sympatho-excitation. However, central mechanisms which relate to the elaboration of angiotensin II (Ang II) and nitric oxide (NO) may also play an important role. Ang II has been shown to be a sympatho-excitatory peptide in the central nervous system while NO is sympatho-inhibitory. Recent studies have demonstrated that blockade of Ang II receptors of the AT(1) subtype augments arterial baroreflex control of sympathetic nerve activity in the heart failure state, thereby predisposing to a reduction in sympathetic tone. Ang II and NO interact to regulate sympathetic outflow. Blockade of NO production in normal conscious rabbits was only capable of increasing sympathetic outflow when accompanied by a background infusion of Ang II. Conversely, providing a source of NO to rabbits with heart failure reduced sympathetic nerve activity when accompanied by blockade of AT(1) receptors. Chronic heart failure is also associated with a decrease in NO synthesis in the brain as indicated by a reduction in the mRNA for the neuronal isoform (nNOS). Chronic blockade of Ang II receptors can up regulate nNOS expression. In addition, exercise training of rabbits with developing heart failure has been shown to reduce sympathetic tone, decrease plasma Ang II, improve arterial baroreflex function and increase nNOS expression in the central nervous system. This review summarizes a large number of studies which have concentrated on the mechanisms of sympatho-excitation in heart failure. It now seems clear that one mechanism which is important in regulating sympathetic outflow in this disease state depends upon a central interaction between Ang II and NO at the cellular and nuclear levels.

Muscle reflex control of sympathetic nerve activity in heart failure: the role of exercise conditioning

Muscle reflex control of sympathetic nerve activity has been an area of considerable investigation. During exercise, the capacity of the peripheral vasculature to dilate far exceeds the maximal attainable levels of cardiac output. The activation of sympathetic nervous system and engagement of the myogenic reflex serve as the controlling influence between the heart and the muscle vasculature to maintain blood pressure (BP). Two basic theories of neural control have evolved. The first termed "central command", suggests that a volitional signal emanating from central motor areas leads to increased sympathetic activation during exercise. According to the second theory the stimulation of mechanical and chemical afferents in exercising muscle lead to engagement of the "exercise pressor reflex". Some earlier studies suggested that group III muscle afferent fibers are predominantly mechanically sensitive whereas unmyelinated group IV muscle afferents respond to chemical stimuli. In recent years new evidence is emerging which challenges the concept of functional differentiation of muscle afferents as well as the classic description of muscle "mechano" and "metabo" receptors. Studies measuring concentrations of interstitial substances during exercise suggest that K(+) and phosphate, but not H(+) and lactate, may be important muscle afferent stimulants. The role of adenosine as a muscle afferent stimulant remains an area of debate. There is strong evidence that sympathetic vasoconstriction due to muscle reflex engagement plays an important role in restricting blood flow to the exercising muscle. In heart failure (HF), exercise leads to premature fatigue and accumulation of muscle metabolites resulting in a greater degree of muscle reflex engagement and in the process further decreasing the muscle blood flow. Conditioning leads to an increased ability of the muscle to maintain aerobic metabolism, lower interstitial accumulation of metabolites, less muscle reflex engagement and a smaller sympathetic response. Beneficial effects of physical conditioning may be mediated by a direct reduction of muscle metaboreflex activity or via reduction of metabolic signals activating these receptors. In this review, we will discuss concepts of flow and reflex engagement in normal human subjects and then contrast these findings with those seen in heart failure (HF). We will then examine the effects of exercise conditioning on these parameters in normal subjects and those with congestive heart failure (CHF).

Dissociation Between Improvement in Left Ventricular Performance and Functional Class in Patients With Chronic Heart Failure

Resting left ventricular ejection fraction (LVEF) and functional capacity do not correlate in chronic heart failure patients treated with digitalis, diuretics, and angiotensin-converting enzyme inhibitors. We sought to determine whether substantial improvement in LVEF, as may occur during long-term beta-blockade or after coronary artery bypass graft (CABG) surgery, leads consistently to improvement in functional class. Doppler echocardiogram and assessment of functional class were obtained at baseline and 12 months after initiation of beta-blockade (87 patients) or CABG surgery (51 patients). At 12 months the effects of beta-blockade were variable: LVEF increased greatly by >or=11% (median value) in 45 patients (52%) and by <11% in 19 (22%), but it decreased or remained unchanged in 23 patients (26%). In contrast, functional class was unchanged or worsened in 59 patients (68%) and improved in only 28 (32%). Similarly, surgery had variable effects on LVEF. LVEF increased by >or=12% (median) in 28 patients (55%) and by <12% in 14 (27%), whereas it decreased or remained unchanged in 9 patients (18%). Functional class was unchanged or worsened in 41 patients (80%) and improved in only 10 (20%). Changes in functional class and LVEF were unrelated for both interventions. Both beta-blockade and CABG surgery improve LVEF in the majority of patients. However, significant improvement in LVEF does not enhance functional capacity consistently in chronic heart failure.

Marathoners or couch potatoes: What is the role of exercise in the management of heart failure?

Patients with chronic heart failure have diminished exercise capacity as a major aspect of their clinical syndrome, regardless of the cause of their left ventricular contractile dysfunction. The mechanisms for the reduction in exercise capacity are multifactorial and include central cardiac, peripheral vascular, respiratory, and skeletal muscle maladaptations that accompany the pathophysiology of heart failure. Increased sympathetic nervous system activity and elevations in circulating neurohormones and cytokines also influence the cardiovascular and metabolic responses to exercise in these patients. Despite the improvements in clinical outcomes with beta-blockers and resynchronization therapy in heart failure patients, their exercise capacity remains substantially reduced when compared with normal age-matched patients. Exercise training has the potential to reverse or improve most of the abnormal physiologic responses to exercise in these patients, and it may serve as adjunctive therapy to standard medical care of these patients. In addition, a body of evidence is being accumulated that suggests that exercise training itself has important secondary prevention benefit in these patients. This review identifies the potential mechanisms whereby exercise training may improve exercise capacity in patients with chronic heart failure and presents the current information regarding clinical outcomes of this therapy.

Réadaptation physique des patients insuffisants cardiaques chroniques

A BENEFICIAL METHOD: Heart failure combines with peripheral vascular and muscular abnormalities that can be effectively improved by rehabilitation. The data in the literature appears to demonstrate the efficacy and excellent tolerance of such exercise. Regarding functional results and improved quality of life, rehabilitation is as equally efficient as the medical treatment that it completes. It can currently be proposed to the majority of patients exhibiting left ventricular systolic dysfunction and who are are only partially improved with medical treatment alone. MODALITIES: The rehabilitation of heart failure must, optimally, be set-up in ambulatory settings, notably within the context of a health care network. Its modalities remain to be specified in on-going studies and its impact on prognosis has to be determined.

Exercise training for patients with heart failure: a systematic review of factors that improve mortality and morbidity

PURPOSE

To determine the efficacy of exercise training and its effects on outcomes in patients with heart failure.

METHODS

MEDLINE, Medscape, and the Cochrane Controlled Trials Registry were searched for trials of exercise training in heart failure patients. Data relating to training protocol, exercise capacity, and outcome measures were extracted and reviewed.

RESULTS

A total of 81 studies were identified: 30 randomized controlled trials, five nonrandomized controlled trials, nine randomized crossover trials, and 37 longitudinal cohort studies. Exercise training was performed in 2387 patients. The average increment in peak oxygen consumption was 17% in 57 studies that measured oxygen consumption directly, 17% in 40 studies of aerobic training, 9% in three studies that only used strength training, 15% in 13 studies of combined aerobic and strength training, and 16% in the one study on inspiratory training. There were no reports of deaths that were directly related to exercise during more than 60,000 patient-hours of exercise training. During the training and follow-up periods of the randomized controlled trials, there were 56 combined (deaths or adverse events) events in the exercise groups and 75 combined events in the control groups (odds ratio [OR] = 0.98; 95% confidence interval [CI]: 0.61 to 1.32; P = 0.60). During this same period, 26 exercising and 41 nonexercising subjects died (OR = 0.71; 95% CI: 0.37 to 1.02; P = 0.06).

CONCLUSION

Exercise training is safe and effective in patients with heart failure. The risk of adverse events may be reduced, but further studies are required to determine whether there is any mortality benefit.

Adjunctive effects of exercise training in heart failure patients receiving maximum pharmacologic therapy

The purpose of this pilot study was to test the adjunctive effects of a 12-week exercise training intervention vs. standard pharmacologic therapy on quality of life, functional status, and mood in heart failure patients. A randomized, two-group repeated measures design was used to test outcomes at baseline and 12 weeks in 23 subjects (ejection fraction <or=40%, standard pharmacologic therapy [diuretics, angiotensin-converting enzyme inhibitors, b blockers, and digoxin] and no change in medical therapy for 30 days). The exercise group had significantly higher adjusted means on the role physical, role emotional, and mental functioning subscales of the Medical Outcomes Study 36-item Short-Form Health Survey compared with the control group. Confusion/bewilderment (Profile of Mood States subscale) adjusted mean scores were significantly lower for the exercise group, indicating better mood compared with the control group. Exercise training provided adjunctive benefit in terms of role and mental functioning for these heart failure patients.

A practical guide to exercise training for heart failure patients

BACKGROUND

Exercise training has been shown to improve exercise capacity in patients with heart failure. We sought to examine the optimal strategy of exercise training for patients with heart failure.

METHODS

Review of the published data on the characteristics of the training program, with comparison of physiologic markers of exercise capacity in heart failure patients and healthy individuals and comparison of the change in these characteristics after an exercise training program.

RESULTS

Many factors, including the duration, supervision, and venue of exercise training; the volume of working muscle; the delivery mode (eg, continuous vs. intermittent exercise), training intensity; and the concurrent effects of medical treatments may influence the results of exercise training in heart failure. Starting in an individually prescribed and safely monitored hospital-based program, followed by progression to an ongoing and progressive home program of exercise appears to be the best solution to the barriers of anxiety, adherence, and "ease of access" encountered by the heart failure patient.

CONCLUSIONS

Various exercise training programs have been shown to improve exercise capacity and symptom status in heart failure, but these improvements may only be preserved with an ongoing maintenance program.

Influence of carvedilol on the benefits of physical training in patients with moderate chronic heart failure

AIMS

To evaluate prospectively the impact of carvedilol on a short-term physical training program in stable patients with moderate chronic heart failure (CHF), and to analyze parameters predictive of improvement after training.

METHODS AND RESULTS

Thirty-eight patients with CHF were referred for cardiac rehabilitation. Etiology was ischemic in 26 patients, dilated in 12 patients and left ventricular ejection fraction was <35%. Patients were classified into three groups: group 1 (n=14)=ACE inhibitors, diuretics and digitalis; group 2 (n=11)=idem group 1+cardioselective beta-blocker; group 3 (n=13)=idem group 1+carvedilol. Exercise tests with VO2 measurement were performed before and after a 4-week exercise training program. Patients with carvedilol experienced a 16.6% increase in peak VO2 which was similar to the 13.9% increase in the group with cardioselective beta-blocker and to the 18.5% in the group without beta-blocker. Moreover non-ischemic etiology of CHF was the only parameter predictive of improvement after training (P=0.02).

CONCLUSION

Addition of carvedilol did not alter benefits of a short-term physical training program in patients with moderate CHF. No baseline characteristic except for etiology of CHF was predictive of a response to training.

Rehabilitation of patients with congestive heart failure with or without beta-blockade therapy

BACKGROUND

Management of heart failure includes beta-blockade (betaB) therapy and cardiac rehabilitation. The aim of this study was to compare the exercise training response of patients with congestive heart failure (CHF) receiving betaB therapy with that of patients not receiving treatment.

METHODS AND RESULTS

Thirty-four consecutive patients with CHF were included in a 4-week training program at their ventilatory threshold (VT); 6 patients received betaB treatment and 18 did not. The patients underwent a cardiopulmonary exercise test before and after training. Oxygen uptake (VO(2)) at peak exercise and at VT increased in both groups (P < or =.0001) without any significant differences between the groups. The same results were found after adjustment to ejection fraction and VO(2) at the start of the training program. There was no difference in VT improvement, measured as a percentage of utilization of maximal oxygen uptake, between the groups. After training, heart rate and ventilation decreased (P < or =.0001) at submaximal levels in both groups without significant differences between the groups.

CONCLUSIONS

betaB therapy does not impair functional improvement induced by a rehabilitation program in patients with CHF. betaB therapy does not interfere with exercise training prescription if patient exercise evaluations are made at the time of therapeutic intake.

Celiprolol augments the effect of physical exercise on insulin sensitivity and serum lipid levels in chronic heart failure

PURPOSE

Impaired insulin sensitivity has been linked with chronic heart failure (CHF). Exercise has a beneficial effect on insulin sensitivity in healthy subjects. It is used also as an adjunctive therapy in patients with CHF. We studied the effect of randomized treatment with celiprolol, a vasodilating beta(1)-adrenoceptor antagonist, 200 mg once daily (n=20) or placebo (n=11) on serum lipid levels and insulin sensitivity in patients with CHF. In addition, all subjects participated in a 6-month exercise training protocol. Thirteen subjects in the celiprolol and eight subjects in the control group were on additional beta(1)-adrenoceptor antagonist as part of their tailored CHF therapy. Insulin sensitivity was determined using the hyperinsulinemic euglycemic clamp test (diabetic subjects excluded, n=11 for the celiprolol group and n=8 for the placebo group).

RESULTS

Insulin sensitivity index (ISI) increased by 33% (P<0.05) in the celiprolol group and by 17% (NS) in the control group. The mean increase in the whole group was 20% [from 68.2+/-11.5 to 81.7+/-10.7 ml/min/kg (mU/l), P<0.05]. No change was found in the total cholesterol level. HDL cholesterol levels increased by 12% (from 0.98+/-0.05 to 1.10+/-0.05 mmol/l, P<0. 005), and HDL/total cholesterol and HDL/LDL cholesterol ratios by 15% and 16%, respectively (P<0.005). The increase in serum fasting HDL cholesterol level was greater in the celiprolol-treated group (P<0.05). At baseline ISI correlated with maximal oxygen uptake (r=0. 65, P<0.0001) and body mass index (r=-0.55, P<0.001). The change in ISI correlated weakly with the improvement in muscle exercise capacity (r=0.53, P<0.05).

CONCLUSIONS

Insulin sensitivity and serum lipid levels may be favorably affected by exercise training in subjects with mild-to-moderate CHF. Celiprolol, a vasodilating beta1- selective adrenoceptor antagonist, potentiates this effect.

Exercise training in heart failure

Patients with heart failure challenge the clinician with a constellation of difficult clinical, pathophysiologic, and psychologic issues. As a result, until recently, exercise training was not considered a safe and effective treatment strategy to be used in these patients. However, in the past 10 years, data from both randomized and nonrandomized trials showed that regular exercise training in patients with stable Class II and III heart failure can safely improve exercise tolerance, attenuate an overactivated sympathetic nervous system, partially reverse skeletal muscle abnormalities, and enhance health-related quality of life. These outcomes are achievable with a relatively moderate dose of physical activity, such as 30 to 60 minutes of walking or cycling 3 to 5 days per week at an intensity equivalent to 60% to 70% of peak oxygen consumption. Sufficiently powered trials are needed to assess morbidity, mortality, and cost-effectiveness endpoints relative to exercise training in patients with heart failure.

Effects of exercise training on limb blood flow in patients with reduced ventricular function

BACKGROUND

Among the factors that contribute to limiting exercise tolerance in chronic heart failure are reduced peripheral blood flow and impaired vasodilatory capacity. Exercise training improves vasodilatory capacity in normal subjects, but controlled studies of exercise training evaluating upper and lower limb blood flow rates have not been performed in patients with reduced ventricular function. Improved vasodilatory capacity could help explain how training increases exercise capacity in these patients.

METHODS

Twenty patients (mean age 55 +/- 6 years) with reduced left ventricular function (mean ejection fraction 32% +/- 6%) after a myocardial infarction were randomized to a 2-month high-intensity residential rehabilitation program or to a control group and were monitored over the subsequent year. Both groups were treated according to current practice with angiotensin-converting enzyme inhibition therapy. Training began 1 month after myocardial infarction. Baseline and postischemic flow rates were measured by plethysmography in both the upper and lower limbs 1 month, 3 months, and 1 year after the infarction. Peak oxygen uptake (VO2) and cardiac output were measured before and after training, and peak VO2 was determined again after 1 year.

RESULTS

After 2 months of training peak VO2 increased 25%, VO2 at the lactate threshold increased 40%, and maximal cardiac output increased from 12.1 +/- 1.6 L/min to 13.9 +/- 2.4 L/min in the exercise group (all p < 0.05), whereas no differences were observed in the control group. At the 1-year follow-up no further increases in peak VO2 were noted in either group, but the higher value persisted in the trained group. However, changes in limb flow rates were poorly related to changes in both peak VO2 and maximal cardiac output. Improvements in baseline and postischemic flow rates occurred mainly in the lower limbs and were observed in the two groups to a similar degree.

CONCLUSION

Exercise training is highly effective in improving exercise capacity in patients with reduced ventricular function after myocardial infarction. These improvements parallel an increase in maximal cardiac output, but they are unrelated to vasodilatory capacity. In patients with reduced ventricular function after myocardial infarction, lower limb vasodilatory capacity improves gradually over the subsequent year, and these improvements occur irrespective of exercise training.

Crosstalk of the heart and periphery: skeletal and cardiac muscle as therapeutic targets in heart failure

Heart failure syndrome is initiated as the body's metabolic needs temporarily exceed the pumping capacity of the heart. In most cases, this phenomenon tends to occur during physical exercise. Although not always subjectively recognized, limited exercise capacity remains the clinical hallmark of congestive heart failure. It can be measured objectively as reduced skeletal muscle performance and maximal whole-body oxygen uptake, which are not necessarily explained by central haemodynamic abnormalities. In fact, the initial cardiac condition sets forth a series of peripheral adaptations that are potentially life-saving during acute decompensation but become disadvantageous and symptom-generating in stable heart failure. Inodilator drugs were theoretically ideal to revert the adverse haemodynamic crosstalk between the heart and periphery. However, these drugs failed to improve prognosis in congestive heart failure, whereas drugs that did so showed typically unimpressive haemodynamic effects. Exercise therapy has recently emerged as a safe and effective way to enhance physical performance and subjective well-being in congestive heart failure. A dual therapeutic approach is suggested, consisting of exercise training to improve the periphery and the use of cardioprotective drugs to limit cardiac cellular damage from neurohormonal activation.