Effects of the HEART Camp Trial on Adherence to Exercise in Patients With Heart Failure.

BACKGROUND: Few exercise training studies in patients with heart failure (HF) report adherence to guideline-recommended 150 minutes of moderate-intensity exercise per week, and no studies have focused on a primary outcome of adherence. METHODS AND RESULTS: This randomized controlled trial evaluated the effect of a multicomponent intervention, Heart Failure Exercise and Resistance Training (HEART) Camp, on adherence to exercise (after 6, 12, and 18 months) compared with an enhanced usual care (EUC) group. Patients (n = 204) were 55.4% male, overall average age was 60.4 years, and 47.5% were nonwhite. The HEART Camp group had significantly greater adherence at 12 (42%) and 18 (35%) months compared with the EUC group (28% and 19%, respectively). No significant difference (P > .05) was found at 6 months. The treatment effect did not differ based on patient's age, race, gender, marital status, type of HF (preserved or reduced ejection fraction) or New York Heart Association functional class. Left ventricular ejection fraction (LVEF) significantly moderated the treatment effect, with greater adherence at higher LVEF. CONCLUSIONS: The multicomponent HEART Camp intervention showed efficacy with significant effects at 12 months and 18 months. Adherence levels remained modest, indicating a need for additional research to address methods and strategies to promote adherence to exercise in patients with HF.

Accelerometer-Measured Daily Activity Levels and Related Factors in Patients With Heart Failure.

BACKGROUND: Few studies report objective accelerometer-measured daily physical activity levels in patients with heart failure (HF). OBJECTIVE: We examined baseline accelerometer-measured physical activity from the Heart Failure Exercise and Resistance Training Camp trial, a federally funded (R01-HL112979) 18-month intervention study to promote adherence to exercise in patients with HF. Factors associated with physical activity levels were also explored. METHODS: Patients with diagnosed HF (stage C chronic HF confirmed by echocardiography and clinical evaluation) were recruited from 2 urban medical centers. Physical activity energy expenditure and the number of minutes of moderate or vigorous physical activity (MVPA) were obtained from 7 full days of measurement with the accelerometer (Actigraph Model GT3X, Pensacola, Florida) for 182 subjects who met minimum valid wear time parameters. Additional measures of health-related factors were included to explore the association with physical activity levels. RESULTS: Subjects had 10.2 ± 10.5 minutes of MVPA per day. Total physical activity energy expenditure was 304 ± 173 kcal on average per day. There were 23 individuals (12.6%) who met the recommended goal of 150 minutes of MVPA per week. Men, whites, New York Heart Association class II, and subjects with better physical function had significantly higher levels of activity. CONCLUSIONS: Consistent with previous research, patients with HF are not meeting recommended guidelines for 150 minutes of MVPA per week.

Cardiac Rehabilitation Improves Fitness in Patients With Subclinical Markers of Cardiotoxicity While Receiving Chemotherapy: A RANDOMIZED CONTROLLED STUDY.

PURPOSE: Heart failure (HF) due to cardiotoxicity is a leading non-cancer-related cause of morbidity and mortality in cancer survivors. Cardiac rehabilitation (CR) improves cardiorespiratory fitness (CRF) and reduces morbidity and mortality in patients with HF, but little is known about its effects on cardiotoxicity in the cancer population. The objective of this study was to determine whether participation in CR improves CRF in patients undergoing treatment with either doxorubicin or trastuzumab who exhibit markers of subclinical cardiotoxicity. METHODS: Female patients with cancer (n = 28: breast, n = 1: leiomyosarcoma) and evidence of subclinical cardiotoxicity (ie, >10% relative decrease in global longitudinal strain or a cardiac troponin of >40 ng·L -1 ) were randomized to 10 wk of CR or usual care. Exercise consisted of 3 d/wk of interval training at 60-90% of heart rate reserve. RESULTS: Cardiorespiratory fitness, as measured by peak oxygen uptake (V˙ o2peak ), improved in the CR group (16.9 + 5.0 to 18.5 + 6.0 mL∙kg -1 ∙min -1 ) while it decreased in the usual care group (17.9 + 3.9 to 16.9 + 4.0 mL∙kg -1 ∙min -1 ) ( P = .009). No changes were observed between groups with respect to high-sensitivity troponin or global longitudinal strain. CONCLUSION: This study suggests that the use of CR may be a viable option to attenuate the reduction in CRF that occurs in patients undergoing cardiotoxic chemotherapy. The long-term effects of exercise on chemotherapy-induced HF warrant further investigation.

New York Heart Association functional class predicts exercise parameters in the current era.

BACKGROUND: The New York Heart Association (NYHA) functional class is a subjective estimate of a patient's functional ability based on symptoms that do not always correlate with the objective estimate of functional capacity, peak oxygen consumption (peak V(O2)). In addition, relationships between these 2 measurements have not been examined in the current medical era when patients are using beta-blockers, aldosterone antagonists, and cardiac resynchronization therapy (CRT). Using baseline data from the HF-ACTION (Heart Failure and A Controlled Trial Investigating Outcomes of Exercise TraiNing) study, we examined this relationship. METHODS: One thousand seven hundred fifty-eight patients underwent a symptom-limited metabolic stress test and stopped exercise due to dyspnea or fatigue. The relationship between NYHA functional class and peak V(O2) was examined. In addition, the effects of beta-blockers, aldosterone antagonists, and CRT therapy on these relationships were compared. RESULTS: The NYHA II patients have a significantly higher peak Vo(2) (16.1 +/- 4.6 vs 13.0 +/- 4.2 mL/kg per minute), a lower ventilation (Ve)/V(CO2) slope (32.8 +/- 7.7 vs 36.8 +/- 10.4), and a longer duration of exercise (11.0 +/- 3.9 vs 8.0 +/- 3.4 minutes) than NYHA III/IV patients. Within each functional class, there was no difference in any of the exercise parameters between patients on or off of beta-blockers, aldosterone antagonists, or CRT therapy. Finally, with increasing age, a significant difference in peak Vo(2), Ve/V(CO2) slope, and exercise time was found. CONCLUSION: For patients being treated with current medical therapy, there still is a difference in true functional capacity between NYHA functional class II and III/IV patients. However, within each NYHA functional class, the presence or absence or contemporary heart failure therapies does not alter exercise parameters.

Challenges with Percent Predicted Maximal V˙O2 in Patients with Heart Failure.

PURPOSE: This study aimed to describe the influence of different equations to predict maximal oxygen uptake (MV˙O2) on the percent predicted MV˙O2 (ppMV˙O2) and the resultant categorization of patients with heart failure with reduced ejection fraction into high or low risk. METHODS: In this retrospective cohort study, ppMV˙O2 was calculated using six different equations to predict MV˙O2 among 1168 patients with heart failure with reduced ejection fraction (33% women). Repeated-measures ANOVA was used to compare within-subject differences in mean ppMV˙O2 between the prediction equations. Cochrane's Q test was used to compare the within-subject difference in the proportion of patients with ppMV˙O2 of <50% (high risk) and ≥75% (low risk) between the prediction equations. RESULTS: The ppMV˙O2 varied significantly (P < 0.001) between the MV˙O2 prediction equations, with mean (10th, 90th percentile) ppMV˙O2 ranging from 39% (25%, 54%) to 60% (39%, 83%) in men and 37% (24%, 49%) to 70% (47%, 94%) in women. Significant variation (P < 0.001) was also observed between prediction equations for the proportion of patients with ppMV˙O2 of <50% and ≥75% in men and women. CONCLUSIONS: Statistically significant and clinically meaningful variations in the ppMV˙O2 are observed on the basis of the reference equation used to predict MV˙O2. Future writing committees should specify the preferred reference equation when identifying a ppMV˙O2 criterion in guideline statements.

Exercise Oscillatory Ventilation: Interreviewer Agreement and a Novel Determination.

INTRODUCTION: Determination of exercise oscillatory ventilation (EOV) is subjective, and the interreviewer agreement has not been reported. The purposes of this study were, among patients with heart failure (HF), as follows: 1) to determine the interreviewer agreement for EOV and 2) to describe a novel, objective, and quantifiable measure of EOV. METHODS: This was a secondary analysis of the HEART Camp: Promoting Adherence to Exercise in Patients with Heart Failure study. EOV was determined through a blinded review by six individuals on the basis of their interpretation of the EOV literature. Interreviewer agreement was assessed using Fleiss kappa (κ). Final determination of EOV was based on agreement by four of the six reviewers. A new measure (ventilation dispersion index; VDI) was calculated for each test, and its ability to predict EOV was assessed with the receiver operator characteristics curve. RESULTS: Among 243 patients with HF (age, 60 ± 12 yr; 45% women), the interreviewer agreement for EOV was fair (κ = 0.303) with 10-s discrete data averages and significantly better, but only moderate (κ = 0.429) with 30-s rolling data averages. Prevalence rates of positive and indeterminate EOVs were 18% and 30% with the 10-s discrete averages and 14% and 13% with the 30-s rolling averages, respectively. VDI was strongly associated with EOV, with areas under the receiver operator characteristics curve of 0.852 to 0.890. CONCLUSIONS: Interreviewer agreement for EOV in patients with HF is fair to moderate, which can negatively affect risk stratification. VDI has strong predictive validity with EOV; as such, it might be a useful measure of prognosis in patients with HF.

Heart Rate and V˙O2 Concordance in Continuous-Flow Left Ventricular Assist Devices.

UNLABELLED: The American College of Sports Medicine currently recommends the HR reserve (HRR) method to guide exercise in individuals who have heart failure with reduced ejection fraction. This recommendation is based on the known association between %HRR and percentage of V˙O2 reserve (%V˙O2R) in this population. However, to our knowledge, no studies exist regarding this relation in individuals with a left ventricular assist device (LVAD). PURPOSE: This article aimed to describe the relation between V˙O2 and surrogate markers of exercise intensity among patients with LVAD. METHODS: Patients with continuous-flow LVAD (n = 24, seven females) completed a symptom-limited graded exercise test on a treadmill. HR and V˙O2 were measured continuously and averaged every 20 s. Regression equations were determined using a generalized estimating equation to predict %V˙O2R from %HRR, Borg RPE, and LVAD flow, overall and stratified by presence of pacing. RESULTS: Although the association between %HRR and %V˙O2R was good (R = 0.75), the slope and y-intercept for %HRR versus %V˙O2R was different from the line of identity (P = 0.002). However, when paced subjects were excluded (n = 8) from the analysis, there was no significant difference between the slope and y-intercept (= 0.036 + 0.937 × %HRR; SEE, 2%; P = 0.052). RPE showed a strong association with %V˙O2R (R = 0.84), whereas LVAD flow showed a weak (albeit statistically significant) association (R = 0.05). Both had slopes and y-intercepts that were different from the line of identity (P < 0.05). CONCLUSIONS: In patients with LVAD who are not paced during exercise, the use of %HRR is a good predictor of %V˙O2R. However, for patients in this population who are also paced during exercise, RPE is a suitable surrogate measure of exercise intensity.

Cardiac rehabilitation improves functional capacity and patient-reported health status in patients with continuous-flow left ventricular assist devices: the Rehab-VAD randomized controlled trial.

OBJECTIVES: This study examined the effects of a cardiac rehabilitation (CR) program on functional capacity and health status (HS) in patients with newly implanted left ventricular assist devices (LVADs). BACKGROUND: Reduced functional capacity and HS are independent predictors of mortality in patients with heart failure. CR improves both, and is related to improved outcomes in patients with heart failure; however, there is a paucity of data that describe the effects of CR in patients with LVADs. METHODS: Enrolled subjects (n = 26; 7 women; age 55 ± 13 years; ejection fraction 21 ± 8%) completed a symptom-limited cardiopulmonary exercise test, the Kansas City Cardiomyopathy Questionnaire (KCCQ), a 6-min walk test (6MW), and single-leg isokinetic strength test before 2:1 randomization to CR versus usual care. Subjects in the CR group underwent 18 visits of aerobic exercise at 60% to 80% of heart rate reserve. Within-group changes from baseline to follow-up were analyzed with a paired t-test, whereas an independent t-test was used to determine differences in the change between groups. RESULTS: Within-group improvements were observed in the CR group for peak oxygen uptake (10%), treadmill time (3.1 min), KCCQ score (14.4 points), 6MW distance (52.3 m), and leg strength (17%). Significant differences among groups were observed for KCCQ, leg strength, and total treadmill time. CONCLUSIONS: Indicators of functional capacity and HS are improved in patients with continuous-flow LVADs who attend CR. Future trials should examine the mechanisms responsible for these improvements, and if such improvements translate into improved clinical outcomes. (Cardiac Rehabilitation in Patients With Continuous Flow Left Ventricular Assist Devices:Rehab VAD Trial [RehabVAD]; NCT01584895).

Muscular strength and cardiorespiratory fitness are associated with health status in patients with recently implanted continuous-flow LVADs.

INTRODUCTION: Patient health status (PHS) and peak oxygen uptake (V.O2) are important predictors of clinical outcomes in individuals with heart failure. Preliminary studies of individuals with left ventricular assist devices (LVADs) show improvements in both PHS and peak V.O2. However, the relationship between peak V.O2 and PHS in this population is not well described. Likewise, data regarding muscular strength are also lacking in this population. We sought to describe the association between peak V.O2, muscular strength, and PHS in patients with continuous-flow LVADs. METHODS: Subjects (n = 26; 7 women) completed a symptom-limited graded exercise test within an average of 82 days (range, 33-167 days) of LVAD implant. In addition, subjects underwent a 6-Minute Walk Test and an isokinetic knee extension strength test and completed the Kansas City Cardiomyopathy Questionnaire (KCCQ). Spearman correlation coefficients were performed, adjusting for body weight and gender, to examine relationships between variables. RESULTS: Muscular strength, as measured by peak torque, and peak V.O2 were both moderately associated with the KCCQ (r = 0.58, P = .006; r = 0.51, P = .019). A subanalysis revealed that muscular strength and peak V.O2 were related to different domains within the KCCQ. CONCLUSIONS: Leg muscle strength and peak V.O2 appear to be important factors related to PHS in patients with continuous-flow LVADs. This is likely partially a result of deconditioning due to recent hospitalization, as well as persistent heart failure-related peripheral maladaptations in skeletal muscle. Incorporating both a cardiovascular as well as strength training program before and after LVAD implant surgery may be beneficial.

Relationship between leg muscle endurance and (.)VE/(.)VCO2 slope in patients with heart failure.

PURPOSE: Ventilatory efficiency, as measured by the slope of the relationship between minute ventilation and carbon dioxide production ((.)VE/(.)VCO2 slope) during cardiopulmonary exercise (CPX) testing, is an important prognostic measure in patients with heart failure (HF). An abnormal slope is linked to the skeletal muscle metaboreflex. In addition, skeletal muscle endurance is reduced in patients with HF. However, the relationship between (.)VE/(.)VCO2 slope and skeletal muscle endurance is not known. This investigation tests the hypothesis that reduced knee extensor muscle endurance is inversely related to an elevated (.)VE/(.)VCO2 slope during CPX testing in patients with HF and that these variables are not related in normal subjects. METHODS: Patients with HF (n = 32) and 6 age-matched normal subjects performed CPX testing and isokinetic dynamometry to determine the (.)VE/(.)VCO2 slope and knee extensor muscle endurance, respectively. RESULTS: The (.)VE/(.)VCO2 slope and leg muscle endurance percentage were significantly related in patients with HF (r = -0.68, P < .001), but not in normal subjects (r = -0.11, P = .83). DISCUSSION: Based on these data, abnormalities of skeletal muscle endurance of patients with HF partially account for (r = 0.46; standard error estimate = 6.6) abnormalities of ventilatory efficiency, as measured by the (.)VE/(.)VCO2 slope. This finding helps explain, in part, the factors that influence an established prognostic indicator, elevated (.)VE/(.)VCO2 slope. Future research is needed to determine whether the relationship between skeletal muscle dysfunction and ventilatory efficiency is directly mediated through the skeletal muscle ergoreflex.