Relation between volume of exercise and clinical outcomes in patients with heart failure.

OBJECTIVES: This study determined whether greater volumes of exercise were associated with greater reductions in clinical events. BACKGROUND: The HF-ACTION (Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training) trial showed that among patients with heart failure (HF), regular exercise confers a modest reduction in the adjusted risk for all-cause mortality or hospitalization. METHODS: Patients randomized to the exercise training arm of HF-ACTION who were event-free at 3 months after randomization were included (n = 959). Median follow-up was 28.2 months. Clinical endpoints were all-cause mortality or hospitalization and cardiovascular mortality or HF hospitalization. RESULTS: A reverse J-shaped association was observed between exercise volume and adjusted clinical risk. On the basis of Cox regression, exercise volume was not a significant linear predictor but was a logarithmic predictor (p = 0.03) for all-cause mortality or hospitalization. For cardiovascular mortality or HF hospitalization, exercise volume was a significant (p = 0.001) linear and logarithmic predictor. Moderate exercise volumes of 3 to <5 metabolic equivalent (MET)-h and 5 to <7 MET-h per week were associated with reductions in subsequent risk that exceeded 30%. Exercise volume was positively associated with the change in peak oxygen uptake at 3 months (r = 0.10; p = 0.005). CONCLUSIONS: In patients with chronic systolic HF, volume of exercise is associated with the risk for clinical events, with only moderate levels (3 to 7 MET-h per week) of exercise needed to observe a clinical benefit. Although further study is warranted to confirm the relationship between volume of exercise completed and clinical events, our findings support the use of regular exercise in the management of these patients.

Efficacy and safety of exercise training in patients with chronic heart failure: HF-ACTION randomized controlled trial.

CONTEXT: Guidelines recommend that exercise training be considered for medically stable outpatients with heart failure. Previous studies have not had adequate statistical power to measure the effects of exercise training on clinical outcomes. OBJECTIVE: To test the efficacy and safety of exercise training among patients with heart failure. DESIGN, SETTING, AND PATIENTS: Multicenter, randomized controlled trial of 2331 medically stable outpatients with heart failure and reduced ejection fraction. Participants in Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training (HF-ACTION) were randomized from April 2003 through February 2007 at 82 centers within the United States, Canada, and France; median follow-up was 30 months. INTERVENTIONS: Usual care plus aerobic exercise training, consisting of 36 supervised sessions followed by home-based training, or usual care alone. MAIN OUTCOME MEASURES: Composite primary end point of all-cause mortality or hospitalization and prespecified secondary end points of all-cause mortality, cardiovascular mortality or cardiovascular hospitalization, and cardiovascular mortality or heart failure hospitalization. RESULTS: The median age was 59 years, 28% were women, and 37% had New York Heart Association class III or IV symptoms. Heart failure etiology was ischemic in 51%, and median left ventricular ejection fraction was 25%. Exercise adherence decreased from a median of 95 minutes per week during months 4 through 6 of follow-up to 74 minutes per week during months 10 through 12. A total of 759 patients (65%) in the exercise training group died or were hospitalized compared with 796 patients (68%) in the usual care group (hazard ratio [HR], 0.93 [95% confidence interval {CI}, 0.84-1.02]; P = .13). There were nonsignificant reductions in the exercise training group for mortality (189 patients [16%] in the exercise training group vs 198 patients [17%] in the usual care group; HR, 0.96 [95% CI, 0.79-1.17]; P = .70), cardiovascular mortality or cardiovascular hospitalization (632 [55%] in the exercise training group vs 677 [58%] in the usual care group; HR, 0.92 [95% CI, 0.83-1.03]; P = .14), and cardiovascular mortality or heart failure hospitalization (344 [30%] in the exercise training group vs 393 [34%] in the usual care group; HR, 0.87 [95% CI, 0.75-1.00]; P = .06). In prespecified supplementary analyses adjusting for highly prognostic baseline characteristics, the HRs were 0.89 (95% CI, 0.81-0.99; P = .03) for all-cause mortality or hospitalization, 0.91 (95% CI, 0.82-1.01; P = .09) for cardiovascular mortality or cardiovascular hospitalization, and 0.85 (95% CI, 0.74-0.99; P = .03) for cardiovascular mortality or heart failure hospitalization. Other adverse events were similar between the groups. CONCLUSIONS: In the protocol-specified primary analysis, exercise training resulted in nonsignificant reductions in the primary end point of all-cause mortality or hospitalization and in key secondary clinical end points. After adjustment for highly prognostic predictors of the primary end point, exercise training was associated with modest significant reductions for both all-cause mortality or hospitalization and cardiovascular mortality or heart failure hospitalization. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00047437.

Effect of exercise training on ventricular function, dyssynchrony, resting myocardial perfusion, and clinical outcomes in patients with heart failure: a nuclear ancillary study of Heart Failure and A Controlled Trial Investigating Outcomes of Exercise TraiNing (HF-ACTION); design and rationale.

BACKGROUND: Technetium Tc 99m gated single photon emission computed tomography (SPECT) has become the cornerstone of noninvasive risk stratification in patients with ischemic heart disease, but its role in patients with heart failure is not as well established. STUDY DESIGN: This study is a substudy of the Heart Failure and A Controlled Trial Investigating Outcomes of Exercise TraiNing (HF-ACTION) trial--a National Institutes of Health/National Heart, Lung, and Blood Institute-funded randomized controlled trial--designed to evaluate the role of exercise training in patients with heart failure due to left ventricular dysfunction. For this substudy, a total of 300 patients distributed on an approximately 1:1 basis between the exercise training and usual care arms of HF-ACTION will undergo resting technetium Tc 99m gated SPECT at baseline and 12 months to compare changes in left ventricular function with exercise training. These changes, along with baseline data, will be correlated with changes in exercise parameters, inflammatory markers, and clinical outcomes: death, cardiovascular hospitalization, and quality of life scores. In a subset of patients, first-pass radionuclide ventriculography will be obtained to assess the relationship between ventricular dyssynchrony, ejection fraction, changes in exercise parameters, and outcomes. CONCLUSION: The role of nuclear imaging in patients with heart failure remains poorly defined. This substudy aims to harness the power of a large heart failure trial (HF-ACTION) to further delineate the utility of technetium Tc 99m gated SPECT imaging and first-pass radionuclide ventriculography for predicting important clinical outcomes in this population.

Heart failure and a controlled trial investigating outcomes of exercise training (HF-ACTION): design and rationale.

BACKGROUND: Although there are limited clinical data to support the use of exercise training as a means to reduce mortality and morbidity in patients with heart failure, current guidelines state that exercise is beneficial. TRIAL DESIGN: The objective of this trial is to determine whether exercise training reduces all-cause mortality or all-cause hospitalization for patients with left ventricular systolic dysfunction and heart failure symptoms. After undergoing baseline assessments to determine whether they can safely exercise, patients are randomized to either usual care or exercise training. Patients in the exercise training arm attend 36 supervised facility-based exercise training sessions. Exercise modalities are cycling or walking. After completing 18 sessions, patients initiate home-based exercise and then transition to solely home-based exercise after completing all 36 sessions. Patients return for facility-based training every 3 months to reinforce their exercise training program. Patients are followed for up to 4 years. Physiologic, quality-of-life, and economic end points that characterize the effect of exercise training in this patient population will be measured at baseline and at intervals throughout the trial. Blood samples will be collected to examine biomarkers such as brain natriuretic peptide, tumor necrosis factor, and C-reactive protein. CONCLUSIONS: Because of its relatively low cost, high availability, and ease of use, exercise training is an intervention that could be accessible to most patients with heart failure. The HF-ACTION trial is designed to definitively assess the effect of exercise training on the clinically relevant end points of mortality, hospitalization, and quality of life in patients with heart failure.