Relation of daily activity levels in patients with chronic heart failure to long-term prognosis

Effects of Comprehensive Outpatient Cardiac Rehabilitation on Exercise Capacity, Functional Status, and Quality of Life in People With Heart Failure: A Systematic Review and Meta-Analysis

PURPOSE

The purpose of this study was to systematically review and conduct a meta-analysis to examine the impact of comprehensive outpatient cardiac rehabilitation on exercise capacity, functional status, and quality of life in patients with heart failure.

METHODS

PubMed, Embase, and CINAHL were searched using keywords and MeSH terms on heart failure and cardiac rehabilitation. Randomized clinical trials published in English using outpatient exercise-based cardiac rehabilitation in patients with heart failure were included. The Grading of Recommendations Assessment, Development, and Evaluation was utilized for quality appraisal. Pooled estimates were computed using standardized mean differences (SMDs) and 95% CIs. Primary outcomes were functional status (6-minute walk distance, quality of life, exercise capacity using peak oxygen consumption, muscle strength, and endurance).

RESULTS

Eleven randomized controlled trials including 1523 participants ranging from 45 to 80 years old and an intervention duration ranging from 2 to 26 weeks were analyzed. Pooled results indicated significant improvements with comprehensive cardiac rehabilitation on 6-minute walk distance (SMD = 0.30; 95% CI = 0.06 to 0.54) and oxygen consumption (SMD = 0.23; 95% CI = 0.06 to 0.40). However, there was no additional benefit for the quality of life beyond that seen in the comparison groups.

CONCLUSION

Results of this study suggest that comprehensive outpatient cardiac rehabilitation is associated with significantly better clinical outcomes than single-component exercise programs in cardiac rehabilitation settings, multicomponent exercise in noncardiac rehabilitation settings, or no exercise.

IMPACT

Heart failure is significantly associated with an increased risk of poor exercise tolerance. Despite the proven benefit of cardiac rehabilitation on exercise tolerance and physical activities from individual randomized clinical trials, questions regarding its impact on clinical outcomes such as exercise capacity, functional status, and quality of life remain inadequate. This systematic review and meta-analysis provides strong evidence supporting comprehensive outpatient cardiac rehabilitation for improving clinical outcomes in heart failure.

Sex-specific differences in the association between steps per day and all-cause mortality among a cohort of adult patients from the United States with congestive heart failure

BACKGROUND

There is a lack of understanding of how daily step counts differentially affect the risk of all-cause mortality in adult with congestive heart failure (CHF) by sex in the United States (US).

OBJECTIVES

To explore the relationship between daily step counts and all-cause mortality in patients with CHF by sex.

METHODS

This is a cohort analysis from the National Health and Nutrition Examination Survey from 2005 to 2006. Multiple Cox hazard regression was performed to explore the association of step counts and all-cause mortality in patients with CHF by sex.

RESULTS

In this study, 363 unweighted samples were enrolled from NHANES 2005-2006, representing about 8.4 million of the US population. Further, 46.28% were women, and the average age was 46 years. Patients with CHF in the more than 5581 steps/day group (HR, 0.31 [95% CI, 0.16-0.58]) had a significantly reduced risk of all-cause mortality compared with the patients in the less 5581 steps/day group after accounting for all covariates. In men, after accounting for all the covariates, there was a significant difference in more than 5581 steps/day group (HR, 0.33 [95% CI, 0.14-0.76]) on all-cause mortality in men with CHF compared with men in the less than 5581 steps/day group.

CONCLUSIONS

Step count is associated with all-cause mortality in patients with CHF. Taking 5581 daily steps was associated with a decreased risk of all-cause mortality in patients with CHF.

Wearable technology and the cardiovascular system: the future of patient assessment

The past decade has seen a dramatic rise in consumer technologies able to monitor a variety of cardiovascular parameters. Such devices initially recorded markers of exercise, but now include physiological and health-care focused measurements. The public are keen to adopt these devices in the belief that they are useful to identify and monitor cardiovascular disease. Clinicians are therefore often presented with health app data accompanied by a diverse range of concerns and queries. Herein, we assess whether these devices are accurate, their outputs validated, and whether they are suitable for professionals to make management decisions. We review underpinning methods and technologies and explore the evidence supporting the use of these devices as diagnostic and monitoring tools in hypertension, arrhythmia, heart failure, coronary artery disease, pulmonary hypertension, and valvular heart disease. Used correctly, they might improve health care and support research.

Physical Therapy for Adults with Heart Failure

Heart failure (HF) is a complex clinical syndrome caused by structural and/or functional abnormalities that results in significant disease burdens not only to the patients and their families but also to the society. Common symptoms/signs of HF include dyspnea, fatigue, and exercise intolerance, which significantly reduce the quality of life of individuals. Since the coronavirus disease 2019 (COVID-19) pandemic in 2019, it has been found that individuals with cardiovascular disease are more vulnerable to COVID-19-related cardiac sequelae including HF. In this article, we review the updated diagnosis, classifications, and interventional guidelines of HF. We also discuss the link between COVID-19 and HF. The latest evidence about physical therapy for patients with HF in both the stable chronic phase and acute cardiac decompensation phase is reviewed. Physical therapy for HF patients with circulatory support devices is also described.

Physical activity and relationship to physical function, quality of life, and cognitive function in older patients with acute decompensated heart failure

BACKGROUND

Volitional physical activity level is predictive of a variety of health outcomes, but has not been examined in patients recently hospitalized for acute decompensated HF (ADHF).

METHODS

Ten to 14 days after index hospitalization for ADHF, 93 participants wore a wrist-mounted triaxial accelerometer (ActiGraph GT3X+) to objectively quantify sedentary behavior, light physical activity, and moderate-to-vigorous physical activity. Levels were compared to 2 groups of age-matched NHANES participants: healthy and chronic, stable HF. The relationship between physical activity levels and physical function [Short Physical Performance Battery (SPPB)], HF-specific quality-of-life (QOL) [Kansas City Cardiomyopathy Questionnaire (KCCQ)], and cognition [Montreal Cognitive Assessment (MOCA)] were examined.

RESULTS

ADHF participants accumulated a median 1,008 (IQR 896, 1,109) minutes of sedentary time, 88 (57, 139) minutes of light physical activity, and 10 (6, 25) minutes of moderate-to-vigorous physical activity per day. Sedentary time, light physical activity, or moderate-to-vigorous activity did not differ by sex or EF subtype. ADHF participants spent only 9% of awake time nonsedentary, compared to 34% and 27% for healthy adults and adults with chronic, stable HF, respectively. Among ADHF participants, SPPB, KCCQ, and MOCA scores did not differ among quartiles of total physical activity.

CONCLUSIONS

Older patients recently hospitalized for ADHF have very low levels of physical activity and high levels of sedentary time, both of which may be potential targets for interventions in this high-risk population. Physical activity level was not significantly associated with objectively measured physical function, QOL, or cognition, suggesting that this measure provides independent information regarding the patient experience of living with HF.

TRIAL REGISTRATION

NCT02196038, https://clinicaltrials.gov/ct2/show/NCT02196038.

Association of objectively measured daily physical activity and health utility to disease severity in chronic heart failure patients: A cross-sectional study

Background and aims

Physical activity (PA) levels are related to mortality and morbidity in patients with chronic heart failure (CHF). Health utility (HU), a very important cost-effectiveness analysis for health care and health status, is measured by several preference-based utility measures. This study aimed to evaluate the relation between PA and HU and the effect of disease severity on PA and HU in patients with CHF.

Methods

We enrolled 226 consecutive outpatients with CHF (mean age, 57.5 years; males, 79.6%) in this retrospective cross-sectional study. Patients were divided into three groups by NYHA class for classification of disease severity. Patient characteristics, average step count in steps/day, PA energy expenditure (PAEE) in kcal/day for 7 days as assessed by accelerometer, and HU assessed by Short Form-6D were compared between the groups.

Results

Average step count (r = 0.37, P < 0.01) and average PAEE (r = 0.36, P < 0.01) correlated positively with HU in all patients. Patients were classified into three groups by NYHA class: class I (n = 92), class II (n = 97), and class III (n = 37). Average step counts (7618.58, 6452.51, and 4225.63 steps/day, P < 0.001), average PAEE (244.65, 176.88, and 103.72 kcal/day, P < 0.001), and HU (0.68, 0.63, and 0.57, P < 0.001) respectively decreased with the increase in NYHA class (P < 0.001).

Conclusion

This study showed a significant relationship of daily PA and HU to disease severity in patients with CHF. Although causation cannot be determined from this study, these results suggest that PA and HU may provide important information related to the severity of disease in patients with CHF.

Early Increased Physical Activity, Cardiac Rehabilitation, and Survival After Implantable Cardioverter-Defibrillator Implantation

BACKGROUND

Increased physical activity (PA) through cardiac rehabilitation (CR) improves outcomes in patients with heart failure and coronary disease, but CR referral remains infrequent. Implantable cardioverter-defibrillators (ICDs) can provide daily PA measurements to patients that may motivate them to increase PA, but it remains unclear if increased ICD measured PA is associated with improved outcomes with and without CR.

METHODS

This is a retrospective observational study of 41 731 Medicare beneficiaries with ICD implantation between January 1, 2014 and December 31, 2016. We linked daily ICD PA measurements and Medicare claims data to determine if increased PA is associated with a reduction in the likelihood of death or heart failure hospitalization. To determine if CR participation altered the effect of PA on outcomes, we performed two additional analyses matching CR participants and nonparticipants using propensity scores. The first match included demographics, comorbidities, and baseline PA measurements. The second match also included the change in PA measured during CR or the same time frame after ICD implant among nonparticipants.

RESULTS

The mean age was 75 (SD, 10) years, 30 182 beneficiaries (72.3%) were male, and 1324 (3%) participated in CR. Increased ICD detected PA was associated with improved survival. CR participants had a mean PA change of +9.7 (SD, 57.8) min/d, whereas nonparticipants had a mean change of -1.0 (SD, 59.7) min/d (P<0.001). After matching for demographics, comorbidities and baseline PA, CR participants had significantly lower 1- to 3-year mortality (hazard ratio, 0.76 [95% CI, 0.69-0.85], P=0.03). After additionally matching for the ICD measured change in PA during CR there were no differences in mortality with and without CR (hazard ratio, 1.00 [95% CI, 0.82-1.21], P=0.87). Every 10 minutes of increased daily PA was associated with a 1.1% reduction in all-cause mortality in both groups.

CONCLUSIONS

Among Medicare beneficiaries with ICDs, small increases in PA were associated with significant reductions in all-cause mortality.

Dynamic factor analysis of seasonal variation in daily physical activity in individuals with heart failure and implanted cardiac devices

BACKGROUND

The purpose of the present study was to determine the presence and magnitude of seasonal variation in daily physical activity (PA) in those with heart failure (HF).

METHODS

Retrospective study and dynamic factor analysis (DFA) of Patient Activity data from Medtronic implanted cardioverter defibrillator and cardiac resynchronization devices (ICD/CRTs).

RESULTS

In a data set of 435 patients, distinct states/trends were identified by DFA including a classic, sinusoidal pattern of seasonal variation and a pattern of decline over the course of 12 months, which were associated with specific clinical characteristics. Overall, model fitting was good.

CONCLUSIONS

Those with low comorbidities, better NYHA Class, higher BMI, no hospitalization, and male sex demonstrated greater seasonal variation of at least 40 min per day between winter (lowest PA) and spring/summer (highest PA). Those with female sex and hospitalization demonstrated overall downward trajectories of approximately 40 and 80 min, respectively, over the course of the year.

Subjective Daily Physical Activity Measures in Heart Disease: A Systematic Review

BACKGROUND

The measurement of daily physical activity (DPA) is important for the prognosis and quantifying clinical outcomes in individuals with heart disease. The measurement of DPA is more feasible using subjective measures when compared with objective measures. The purpose of this systematic review of the literature was to identify the subjective measures of DPA that have established reliability and validity in individuals with heart disease to assist clinician and researcher instrument selection.

METHODS

A systematic search of PubMed, CINAHL, MEDLINE, and ProQuest databases was performed. Methodological rigor was assessed using 3 different quality appraisal tools. Qualitative synthesis of included studies was performed.

RESULTS

Twenty-two unique studies covering 19 subjective DPA measures were ultimately included. Methodological rigor was generally fair, and validity coefficients were moderate at best.

CONCLUSIONS

Only 4 subjective measures that have established test-retest reliability and that provide an estimate of energy expenditure, metabolic equivalents, or minutes of DPA were compared against accelerometry or a DPA diary in patients with heart disease: SWISS Physical Activity Questionnaire, Total Activity Measure 1 and 2, and Mobile Physical Activity Logger. Depending on the clinician or researcher needs, instrument selection would depend on the recall period and the DPA construct being measured.

Multiparameter diagnostic sensor measurements during clinically stable periods and worsening heart failure in ambulatory patients

Aims

This study aims to characterize the range of implantable device‐based sensor values including heart sounds, markers of ventilation, thoracic impedance, activity, and heart rate for patients with heart failure (HF) when patients were deemed to be in clinically stable periods against the time course of acute decompensation and recovery from HF events.

Methods and results

The MultiSENSE trial followed 900 patients implanted with a COGNIS CRT‐D for up to 1 year. Chronic, ambulatory diagnostic sensor data were collected and evaluated during clinically stable periods (CSP: unchanged NYHA classification, no adverse events, and weight change ≤2.27 kg), and in the timeframe leading up to and following HF events (HF admissions or unscheduled visits with intravenous HF treatment). Physiologic sensor data from 1667 CSPs occurring in 676 patients were compared with those data leading up to and following 192 HF events in 106 patients. Overall, the mean age was 66.6 years, and the population were predominantly male (73%). Patients were primarily in NYHA II (67%), with a mean LVEF of 29.6% and median NT‐proBNP of 754.5 pg/mL. Sensor values during CSP were poorer in patients who had HF events during the study period than those without HF events, including first heart sound (S1: 2.18 ± 0.84 mG vs. 2.62 ± 0.95 mG, P = 0.002), third heart sound (S3: 1.13 ± 0.36 mG vs. 0.91 ± 0.30 mG, P < 0.001), thoracic impedance (45.66 ± 8.78 Ohm vs. 50.33 ± 8.43 Ohm, P < 0.001), respiratory rate (19.09 ± 3.10 br/min vs. 17.66 ± 2.39 br/min, P = 0.002), night time heart rate (73.39 ± 8.36 b.p.m. vs. 69.56 ± 8.09 b.p.m., P = 0.001), patient activity (1.69 ± 1.84 h vs. 2.56 ± 2.20 h, P = 0.006), and HeartLogic index (11.07 ± 12.14 vs. 5.31 ± 5.13, P = 0.001). Sensor parameters measured worsening status leading up to HF events with recovery of values following treatment.

Conclusions

Device‐based physiologic sensors not only revealed progressive worsening leading up to HF events but also differentiated patients at increased risk of HF events when presumed to be clinically stable.

Wearable devices can predict the outcome of standardized 6-minute walk tests in heart disease

Wrist-worn devices with heart rate monitoring have become increasingly popular. Although current guidelines advise to consider clinical symptoms and exercise tolerance during decision-making in heart disease, it remains unknown to which extent wearables can help to determine such functional capacity measures. In clinical settings, the 6-minute walk test has become a standardized diagnostic and prognostic marker. We aimed to explore, whether 6-minute walk distances can be predicted by wrist-worn devices in patients with different stages of mitral and aortic valve disease. A total of n = 107 sensor datasets with 1,019,748 min of recordings were analysed. Based on heart rate recordings and literature information, activity levels were determined and compared to results from a 6-minute walk test. The percentage of time spent in moderate activity was a predictor for the achievement of gender, age and body mass index-specific 6-minute walk distances (p < 0.001; R 2 = 0.48). The uncertainty of these predictions is demonstrated.

Utility of single-item questions to assess physical inactivity in patients with chronic heart failure

Aim

The purpose of this study was to explore the utility of two single‐item self‐report (SR) questions to assess physical inactivity in patients with heart failure (HF).

Methods and results

This is a cross‐sectional study using data from 106 patients with HF equipped with accelerometers for 1 week each. Two SR items relating to physical activity were also collected. Correlations between accelerometer activity counts and the SR items were analysed. Patients were classified as physically active or inactive on the basis of accelerometer counts, and the SR items were used to try to predict that classification. Finally, patients were classified as having high self‐reported physical activity or low self‐reported physical activity, on the basis of the SR items, and the resulting groups were analysed for differences in actual physical activity. There were significant but weak correlations between the SR items and accelerometer counts: ρ = 0.24, P = 0.016 for SR1 and ρ = 0.21, P = 0.033 for SR2. Using SR items to predict whether a patient was physically active or inactive produced an area under the curve of 0.62 for SR1, with a specificity of 92% and a sensitivity of 30%. When dividing patients into groups on the basis of SR1, there was a significant difference of 1583 steps per day, or 49% more steps in the high self‐reported physical activity group (P < 0.001).

Conclusions

There might be utility in the single SR question for high‐specificity screening of large populations to identify physically inactive patients in order to assign therapeutic interventions efficiently where resources are limited.

Self-reported and objectively measured physical activity in people with and without chronic heart failure: UK Biobank analysis

Objective

The impact of heart failure (HF) on perceived and objectively measured levels of physical activity (PA) can inform risk stratification and treatment recommendation. We aimed to compare self-reported and objectively measured PA levels in a large sample of participants with and without HF.

Methods

A validated PA questionnaire was used to estimate self-reported weekly PA among 1600 participants with HF and 387 580 participants without HF. Accelerometer data were studied in 596 participants with HF and 96 105 participants without HF for a period of 7 days. Using multivariable linear regression models, we compared the PA levels between participants with HF and without HF, focusing on both the average daily PA levels and the intensity of PAs throughout the day.

Results

PA levels were significantly lower in participants with HF using both self-report (excess metabolic equivalent of task hours per week of 26.5 (95% CI 24.7 to 28.4) vs 34.7 (95% CI 34.5 to 34.9), respectively (p<0.001)) and accelerometer measures (mean accelerations of 23.7 milligravity (95% CI 23.1 to 24.4) vs 28.1 milligravity (95% CI 28.0 to 28.1), respectively (p<0.001)). Findings were consistent across different PA intensities. Hour-by-hour comparisons showed that accelerometer-derived PA levels of patients with HF were reduced throughout the day.

Conclusion

Perceived and objectively recorded PA levels of patients with chronic HF are significantly lower than those of individuals without HF. This difference is continuous throughout the different hours of the day, with individuals with HF being on average 16% less active than individuals without HF. In patients with HF, increases in everyday activity may be a potential alternative to structured exercise programmes.

Association of Implantable Device Measured Physical Activity With Hospitalization for Heart Failure

OBJECTIVES

The purpose of this study was to evaluate the association of physical activity (PA) level and longitudinal PA trajectory with a composite heart failure hospitalization and mortality endpoint over a 5-year follow-up period following implantation.

BACKGROUND

Low device measured PA early after implantation of an implantable cardioverter-defibrillator (ICD) or cardiac resynchronization therapy defibrillator (CRT-D) is associated with poor outcomes.

METHODS

We linked daily PA data from the Boston Scientific ALTITUDE dataset of patients with ICD or CRT-D implantation to Medicare claims data. We used a joint model to investigate the association of the composite endpoint with 1) the time-varying point estimate of PA and 2) the time-varying trajectory/slope of PA during follow-up.

RESULTS

Among 20,927 patients with median activity level 85 min/day, 14.1% and 49.6% experienced the composite endpoint at 1 and 5 years. Adjusted joint model results showed that there was a 1.13 (95% confidence interval: 1.12 to 1.13)-fold increase in the hazard of the composite endpoint for 75 min of daily PA relative to 85 min of PA; and a within-patient 10-min decrease in average daily PA over an 8-week period from 85 to 75 min was associated with a hazard ratio of 4.02 (95% confidence interval: 3.82 to 4.22) for the composite endpoint.

CONCLUSIONS

Patients with large decreases in PA have significantly higher risk of experiencing heart failure hospitalization or death. PA data from implantable devices may identify patients before clinical decompensation.

Physical Therapist Clinical Practice Guideline for the Management of Individuals With Heart Failure

The American Physical Therapy Association (APTA), in conjunction with the Cardiovascular and Pulmonary Section of APTA, have commissioned the development of this clinical practice guideline to assist physical therapists in their clinical decision making when managing patients with heart failure. Physical therapists treat patients with varying degrees of impairments and limitations in activity and participation associated with heart failure pathology across the continuum of care. This document will guide physical therapist practice in the examination and treatment of patients with a known diagnosis of heart failure. The development of this clinical practice guideline followed a structured process and resulted in 9 key action statements to guide physical therapist practice. The level and quality of available evidence were graded based on specific criteria to determine the strength of each action statement. Clinical algorithms were developed to guide the physical therapist in appropriate clinical decision making. Physical therapists are encouraged to work collaboratively with other members of the health care team in implementing these action statements to improve the activity, participation, and quality of life in individuals with heart failure and reduce the incidence of heart failure-related re-admissions.

Usefulness of Modern Activity Trackers for Monitoring Exercise Behavior in Chronic Cardiac Patients: Validation Study

BACKGROUND

Improving physical activity (PA) is a core component of secondary prevention and cardiac (tele)rehabilitation. Commercially available activity trackers are frequently used to monitor and promote PA in cardiac patients. However, studies on the validity of these devices in cardiac patients are scarce. As cardiac patients are being advised and treated based on PA parameters measured by these devices, it is highly important to evaluate the accuracy of these parameters in this specific population.

OBJECTIVE

The aim of this study was to determine the accuracy and responsiveness of 2 wrist-worn activity trackers, Fitbit Charge 2 (FC2) and Mio Slice (MS), for the assessment of energy expenditure (EE) in cardiac patients.

METHODS

EE assessed by the activity trackers was compared with indirect calorimetry (Oxycon Mobile [OM]) during a laboratory activity protocol. Two groups were assessed: patients with stable coronary artery disease (CAD) with preserved left ventricular ejection fraction (LVEF) and patients with heart failure with reduced ejection fraction (HFrEF).

RESULTS

A total of 38 patients were included: 19 with CAD and 19 with HFrEF (LVEF 31.8%, SD 7.6%). The CAD group showed no significant difference in total EE between FC2 and OM (47.5 kcal, SD 112 kcal; P=.09), in contrast to a significant difference between MS and OM (88 kcal, SD 108 kcal; P=.003). The HFrEF group showed significant differences in EE between FC2 and OM (38 kcal, SD 57 kcal; P=.01), as well as between MS and OM (106 kcal, SD 167 kcal; P=.02). Agreement of the activity trackers was low in both groups (CAD: intraclass correlation coefficient [ICC] FC2=0.10, ICC MS=0.12; HFrEF: ICC FC2=0.42, ICC MS=0.11). The responsiveness of FC2 was poor, whereas MS was able to detect changes in cycling loads only.

CONCLUSIONS

Both activity trackers demonstrated low accuracy in estimating EE in cardiac patients and poor performance to detect within-patient changes in the low-to-moderate exercise intensity domain. Although the use of activity trackers in cardiac patients is promising and could enhance daily exercise behavior, these findings highlight the need for population-specific devices and algorithms.

Using wearable technology to predict health outcomes: a literature review

Objective

To review and analyze the literature to determine whether wearable technologies can predict health outcomes.

Materials and methods

We queried Ovid Medline 1946 -, Embase 1947 -, Scopus 1823 -, the Cochrane Library, clinicaltrials.gov 1997 – April 17, 2018, and IEEE Xplore Digital Library and Engineering Village through April 18, 2018, for studies utilizing wearable technology in clinical outcome prediction. Studies were deemed relevant to the research question if they involved human subjects, used wearable technology that tracked a health-related parameter, and incorporated data from wearable technology into a predictive model of mortality, readmission, and/or emergency department (ED) visits.

Results

Eight unique studies were directly related to the research question, and all were of at least moderate quality. Six studies developed models for readmission and two for mortality. In each of the eight studies, data obtained from wearable technology were predictive of or significantly associated with the tracked outcome.

Discussion

Only eight unique studies incorporated wearable technology data into predictive models. The eight studies were of moderate quality or higher and thereby provide proof of concept for the use of wearable technology in developing models that predict clinical outcomes.

Conclusion

Wearable technology has significant potential to assist in predicting clinical outcomes, but needs further study. Well-designed clinical trials that incorporate data from wearable technology into clinical outcome prediction models are required to realize the opportunities of this advancing technology.

Impact of Cardiac Resynchronization Therapy on Daily Physical Activity in Heart Failure Patients

PURPOSE

Cardiac resynchronization therapy (CRT) has emerged as a beneficial therapy for heart failure (HF) patients. It has been shown to enhance cardiac pump function and increase exercise capacity in patients with HF who display wide QRS complex on their electrocardiogram. To date, few studies have assessed daily physical activity (PA) in CRT patients. The objective of this pilot study was to assess the impact of CRT on the physical function and daily PA of HF patients who met the standard indications for CRT implantation.

METHODS

The daily PA of 18 CRT patients was measured using a SenseWear Armband for ∼3 d. Daily PA measurements included steps/d and time spent sedentary (≤1.5 metabolic equivalent tasks), in light PA (1.6-2.9 metabolic equivalent tasks), and in moderate-vigorous PA (≥3 metabolic equivalent tasks). To assess exercise capacity, a 6-min walk test was performed pre- and post-CRT.

RESULTS

There was no significant change in the 6-min walk test distance from pre- to post-CRT (383 ± 99 m at baseline vs 402 ± 104 m post-CRT). There was a decrease in total steps/d from 3405 ± 2334 pre-CRT to 2553 ± 1692 post-CRT (P = .017). Furthermore, no significant changes were observed pre- to post-CRT with regard to the additional PA assessments.

CONCLUSIONS

Our patients exhibited a sedentary lifestyle pre- and post-CRT. These findings underscore the need for a cardiac rehabilitation program that encourages post-CRT patients to decrease sedentary time.

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.

Validity of six consumer-level activity monitors for measuring steps in patients with chronic heart failure

INTRODUCTION

Although numerous activity trackers have been validated in healthy populations, validation is lacking in chronic heart failure patients who normally walk at a slower pace, making it difficult for researchers and clinicians to implement activity monitors during physical activity interventions.

METHODS

Six consumer-level activity monitors were validated in a 3-day field study in patients with chronic heart failure and healthy individuals under free living conditions. Furthermore, the same devices were evaluated in a lab-based study during treadmill walking at speeds of 2.4, 3.0, 3.6, and 4.2 km·h-1. Concordance correlation coefficients (CCC) were used to evaluate the agreement between the activity monitors and the criterion, and mean absolute percentage errors (MAPE) were calculated to assess differences between each device and the criterion (MAPE <10% was considered as a threshold for validity).

RESULTS

In the field study of healthy individuals, all but one of the activity monitors showed a substantial correlation (CCC ≥0.95) with the criterion device and MAPE <10%. In patients with heart failure, the correlation of only two activity monitors (Garmin vívofit 3 and Withings Go) was classified as at least moderate (CCC ≥0.90) and none of the devices had MAPE <10%. In the lab-based study at speeds 4.2 and 3.6 km·h-1, all activity monitors showed substantial to almost perfect correlations (CCC ≥0.95) with the criterion and MAPE in the range 1%-3%. However, at slower speeds of 3.0 and 2.4 km·h-1, the accuracy of all devices substantially deteriorated: their correlation with the criterion decreased below 90% and their MAPE increased to 4-8% and 10-45%, respectively.

CONCLUSIONS

Even though none of the tested activity monitors fall within arbitrary thresholds for validity, most of them perform reasonably well enough to be useful tools that clinicians can use to simply motivate chronic heart failure patients to walk more.

Influence of Baseline Physical Activity Level on Exercise Training Response and Clinical Outcomes in Heart Failure: The HF-ACTION Trial

OBJECTIVES

This study sought to evaluate the influence of baseline physical activity (PA) on responses to aerobic exercise training and clinical events in outpatients with chronic systolic heart failure (HF) from the multicenter HF-ACTION (Exercise Training Program to Improve Clinical Outcomes in Individuals With Congestive Heart Failure) trial.

BACKGROUND

The influence of baseline PA on exercise capacity, responses to exercise training and clinical outcomes in patients with chronic HF is unclear.

METHODS

Of 2,130 participants who provided consent for this analysis, 1,494 patients (64%) had complete baseline PA data, using a modified version of the International Physical Activity Questionnaire-Short Form questionnaire and were included in the analysis; 742 received usual care and 752 were allocated to the exercise training group. Changes in exercise capacity, all-cause mortality and hospitalization, cardiovascular (CV) mortality and hospitalization, and CV mortality and HF hospitalization were evaluated as a function of baseline PA tertile.

RESULTS

At baseline, the highest PA tertile showed greater peak oxygen uptake, cardiopulmonary exercise test duration, and 6-min walk test distance than the other 2 PA tertiles, as well as lower New York Heart Association functional class, lower Beck depression score, and lower atrial fibrillation prevalence than the lowest PA tertile. Compared to the lowest PA tertile, the middle tertile had 18% lower risk of CV death/CV hospitalizations, and the upper tertile showed 23% lower risk of CV death/HF hospitalizations. Exercise capacity and clinical outcome responses to training were similar and largely nonsignificant across baseline PA tertiles with significant benefit of training on exercise test duration for all tertiles.

CONCLUSIONS

In patients with chronic systolic HF, aerobic exercise training significantly improves exercise test duration to a similar extent across baseline PA tertiles. Although higher baseline PA was associated with lower risk of clinical events, no significant differences in event rates within each PA tertile were seen between subgroups randomized to exercise training versus usual care. (Exercise Training Program to Improve Clinical Outcomes in Individuals With Congestive Heart Failure [HF-ACTION]; NCT00047437).

Physical Activity Measured by Implanted Devices Predicts Atrial Arrhythmias and Patient Outcome: Results of IMPLANTED (Italian Multicentre Observational Registry on Patients With Implantable Devices Remotely Monitored)

Background

To determine whether daily physical activity (PA), as measured by implanted devices (through accelerometer sensor), was related to the risk of developing atrial arrhythmias during long‐term follow‐up in a population of heart failure (HF) patients with an implantable cardioverter defibrillator (ICD).

Methods and Results

The study population was divided into 2 equally sized groups (PA cutoff point: 3.5 h/d) according to their mean daily PA recorded by the device during the 30‐ to 60‐day period post‐ICD implantation. Propensity score matching was used to compare 2 equally sized cohorts with similar characteristics between lower and higher activity patients. The primary end point was time free from the first atrial high‐rate episode (AHRE) of duration ≥6 minutes. Secondary end points were: first AHRE ≥6 hours, first AHRE ≥48 hours, and a combined end point of death or HF hospitalization. Data from 770 patients (65±15 years; 66% men; left ventricular ejection fraction 35±12%) remotely monitored for a median of 25 months were analyzed. A PA ≥3.5 h/d was associated with a 38% relative reduction in the risk of AHRE ≥6 minutes (72‐month cumulative survival: 75.0% versus 68.1%; log rank P=0.025), and with a reduction in the risk of AHRE ≥6 hours, AHRE ≥48 hours, and the combined end point of death or HF hospitalization (all P<0.05).

Conclusions

In HF patients with ICD, a low level of daily PA was associated with a higher risk of atrial arrhythmias, regardless of the patients' baseline characteristics. In addition, a lower daily PA predicted death or HF hospitalization.

Yoga for Heart Failure: A Review and Future Research

Background:

Complementary and alternative medicine is a rapidly growing area of biomedical inquiry. Yoga has emerged in the forefront of holistic medical care due to its long history of linking physical, mental, and spiritual well-being. Research in yoga therapy (YT) has associated improved cardiovascular and quality of life (QoL) outcomes for the special needs of heart failure (HF) patients.

Aim:

The aim of this study is to review yoga intervention studies on HF patients, discuss proposed mechanisms, and examine yoga's effect on physiological systems that have potential benefits for HF patients. Second, to recommend future research directions to find the most effective delivery methods of yoga to medically stable HF patients.

Methods:

The authors conducted a systematic review of the medical literature for RCTs involving HF patients as participants in yoga interventions and for studies utilizing mechanistic theories of stretch and new technologies. We examined physical intensity, mechanistic theories, and the use of the latest technologies.

Conclusions:

Based on the review, there is a need to further explore yoga mechanisms and research options for the delivery of YT. Software apps as exergames developed for use at home and community activity centers may minimize health disparities and increase QoL for HF patients.

Harnessing the Potential of Wearable Activity Trackers for Heart Failure Self-Care

PURPOSE OF REVIEW

The purpose of this study was to explore the potential of wearable activity trackers to promote self-care management for physical activity in heart failure (HF).

RECENT FINDINGS

Exercise participation decreases hospital admissions and improves quality of life in HF, and activity tracking devices provide more precise means to assess free-living physical activity and thus enable tailored exercise instruction. Use of activity trackers by cardiac patients for self-monitoring and motivational purposes is associated with increased levels of physical activity and is predictive of disease severity. However, more research is required to establish the feasibility and validity of these devices in HF patients. It is also critical that the devices can be easily used to collect, process and utilise relevant data. Activity trackers have the potential to promote HF self-care because they provide monitoring of physical activity behaviours and the potential to generate habit formation and goal reinforcement, all of which foster physical activity.

Effect of a 6-month pedometer-based walking intervention on functional capacity in patients with chronic heart failure with reduced (HFrEF) and with preserved (HFpEF) ejection fraction: study protocol for two multicenter randomized controlled trials

Background

Regular physical activity is recommended for patients with chronic heart failure to improve their functional capacity, and walking is a popular, effective, and safe form of physical activity. Pedometers have shown potential to increase the amount of walking across a range of chronic diseases, but it is unknown whether a pedometer-based intervention improves functional capacity and neurohumoral modulation in heart failure patients.

Methods

Two multicenter randomized controlled trials will be conducted in parallel: one in patients with chronic heart failure with reduced ejection fraction (HFrEF), the other in patients with chronic heart failure with preserved ejection fraction (HFpEF). Each trial will consist of a 6-month intervention with an assessment at baseline, at 3 months, at the end of the intervention, and 6 months after completing the intervention. Each trial will aim to include a total of 200 physically inactive participants with chronic heart failure who will be randomly assigned to intervention or control arms. The 6-month intervention will consist of an individualized pedometer-based walking program with weekly step goals, behavioral face-to-face sessions with a physician, and regular telephone calls with a research nurse. The intervention will be based on effective behavioral principles (goal setting, self-monitoring, personalized feedback). The primary outcome is the change in 6-min walk distance at the end of the 6-month intervention. Secondary outcomes include changes in serum biomarkers levels, pulmonary congestion assessed by ultrasound, average daily step count measured by accelerometry, anthropometric measures, symptoms of depression, health-related quality of life, self-efficacy, and MAGGIC risk score.

Discussion

To our knowledge, these are the first studies to evaluate a pedometer-based walking intervention in patients with chronic heart failure with either reduced or preserved ejection fraction. The studies will contribute to a better understanding of physical activity promotion in heart failure patients to inform future physical activity recommendations and heart failure guidelines.

Trial registration The trials are registered in ClinicalTrials.gov, identifiers: NCT03041610, registered 29 January 2017 (HFrEF), NCT03041376, registered 1 February 2017 (HFpEF)

Exercise- and Psychosocial-Based Interventions to Improve Daily Activity in Heart Failure: A Pilot Study

In individuals with heart failure (HF), low daily activity is associated with a poorer prognosis. The purpose of this pilot study was to investigate the effects of two home-based interventions on the primary HF-related outcome of daily activity and secondary outcomes of exercise tolerance, HF-related health status, and lower extremity functional strength in 16 patients with HF and implanted Medtronic implantable cardioverter defibrillator and cardiac resynchronization devices using a single-blind, randomized controlled pilot trial. Interventions were either daily activity feedback and encouragement or health coaching and home-based exercise. There were no significant differences in primary or secondary outcomes either between or within groups. Three subjects in each treatment group improved in two or more secondary outcomes, and only one improved in daily activity. Although the present pilot study incorporated both exercise and psychosocial components in the intervention, there was no effect on daily activity, perhaps because readiness for behavioral change was not accounted for either in group stratification/allocation or inclusion criteria.

Associations between heart failure and physical function in US adults

BACKGROUND

There is a paucity of nationally representative data in the area of heart failure (HF) and physical function (PF).

AIM

Examine the relationship(s) between HF and PF in a nationally representative sample of United States (US) adults.

DESIGN

Cross-section analysis of US adults.

METHODS

Sample (n = 6623) included adult (≥40 years of age) participants from the 1999-2006 National Health and Nutrition Examination Survey. Participants reporting HF answered questions related to their abilities to accomplish specific upper extremity and lower extremity tasks, and household chores.

RESULTS

Prevalence estimates of reporting much difficulty or the inability to stand from an armless chair was 9.9% and 4.3% (P = 0.002) in those with and without HF, respectively. Similar estimates were revealed for much difficulty or inability to lift or carry 10 pounds (16.8% and 8.6%, P = 0.0004) and much difficulty or inability to do household chores (13.3% and 6.1%, P = 0.0008). Following adjustments participants reporting HF had significantly greater odds of reporting much difficulty or the inability to stand from an armless chair [odds ratio (OR) 1.93; 95% confidence intervals (CI) 1.25, 2.96], much difficulty or the inability to lift or carry 10 lbs (OR 1.90; 95% CI 1.36, 2.65) and much difficulty or inability to do household chores (OR 2.06; 95% CI 1.41, 3.02) compared with participants not reporting HF.

CONCLUSIONS

Findings suggest US adults reporting HF are more likely to report poorer PF.

Seasonal variation of daily physical activity in individuals with heart failure

BACKGROUND

Previous studies indicate that seasonal variation affects daily physical activity (PA), but none have investigated this relationship in individuals with heart failure (HF) who also have implanted cardioverter defibrillators and cardiac resynchronization therapy (ICD/CRT) devices. The purpose of the present study was to determine if seasonal variation in temperature affects daily PA in patients with HF and ICD/CRTs.

PATIENTS AND METHODS

Secondary analysis of data from 16 subjects with HF and Medtronic® ICD/CRT devices enrolled in a randomized trial investigating interventions to improve daily PA. Due to the rolling study enrollment, daily PA data for all subjects were not available for the entire time frame and were divided into two groups. Determination of seasonal variation of daily PA was determined using visual analysis of daily PA plotted with average temperature, autocorrelation, visual analysis of seasonal subseries plots and boxplot analysis, as well as Wilcoxon signed-rank tests.

RESULTS

Subjects 1-8 demonstrated the greatest differences in daily PA during periods of seasonal transition whereas subjects 9-16 demonstrated the greatest variation in daily PA with greatest seasonal temperature difference. Wilcoxon signed-rank testing of the lowest and highest months for daily PA revealed median differences of 0.30 (p = 0.050) and 0.36 hours (p = 0.036) for subjects 1-8 and 9-16, with effect sizes of 0.69 and 0.74, respectively.

CONCLUSIONS

Seasonal variation in mean temperature appears to affect daily PA in individuals with HF and ICD/CRT devices by a magnitude of 0.30-0.36 hours, which may need to be accounted for in future research investigating interventions to improve daily PA.

A Wearable Patch to Enable Long-Term Monitoring of Environmental, Activity and Hemodynamics Variables

We present a low power multi-modal patch designed for measuring activity, altitude (based on high-resolution barometric pressure), a single-lead electrocardiogram, and a tri-axial seismocardiogram (SCG). Enabled by a novel embedded systems design methodology, this patch offers a powerful means of monitoring the physiology for both patients with chronic cardiovascular diseases, and the general population interested in personal health and fitness measures. Specifically, to the best of our knowledge, this patch represents the first demonstration of combined activity, environmental context, and hemodynamics monitoring, all on the same hardware, capable of operating for longer than 48 hours at a time with continuous recording. The three-channels of SCG and one-lead ECG are all sampled at 500 Hz with high signal-to-noise ratio, the pressure sensor is sampled at 10 Hz, and all signals are stored to a microSD card with an average current consumption of less than 2 mA from a 3.7 V coin cell (LIR2450) battery. In addition to electronic characterization, proof-of-concept exercise recovery studies were performed with this patch, suggesting the ability to discriminate between hemodynamic and electrophysiology response to light, moderate, and heavy exercise.

Physiological basis of cardiopulmonary rehabilitation in patients with lung or heart disease

Educational Aims

Summary

Shortness of breath associated with cardiorespiratory abnormalities and peripheral muscle discomfort are the major factors that limit exercise capacity in patients with chronic obstructive pulmonary disease (COPD) and those with congestive heart failure (CHF). Both of these symptoms negatively impact on patients’ daily physical activity levels. In turn, poor daily physical activity is commonly associated with increased rates of morbidity and mortality. Cardiopulmonary rehabilitation programmes partially reverse muscle weakness and dysfunction and increase functional capacity in both COPD and CHF. However, benefits gained from participation in cardiopulmonary rehabilitation programmes are regressing soon after the completion of these programmes. Moreover, several barriers limit access and uptake of cardiopulmonary rehabilitation programmes by eligible patients. A potential solution to the underutilisation of cardiopulmonary rehabilitation is the implementation of tele-rehabilitation interventions at home using information and communications technologies. Thus, tele-rehabilitation may be useful to encourage and educate patients with COPD or CHF on how best to maintain and/or further enhance daily physical activity levels.

Gender-related differences in maximum gait speed and daily physical activity in elderly hospitalized cardiac inpatients: a preliminary study

Maximum gait speed and physical activity (PA) relate to mortality and morbidity, but little is known about gender-related differences in these factors in elderly hospitalized cardiac inpatients. This study aimed to determine differences in maximum gait speed and daily measured PA based on sex and the relationship between these measures in elderly cardiac inpatients.A consecutive 268 elderly Japanese cardiac inpatients (mean age, 73.3 years) were enrolled and divided by sex into female (n = 75, 28%) and male (n = 193, 72%) groups. Patient characteristics and maximum gait speed, average step count, and PA energy expenditure (PAEE) in kilocalorie per day for 2 days assessed by accelerometer were compared between groups.Gait speed correlated positively with in-hospital PA measured by average daily step count (r = 0.46, P < 0.001) and average daily PAEE (r = 0.47, P < 0.001) in all patients. After adjustment for left ventricular ejection fraction, step counts and PAEE were significantly lower in females than males (2651.35 ± 1889.92 vs 4037.33 ± 1866.81 steps, P < 0.001; 52.74 ± 51.98 vs 99.33 ± 51.40 kcal, P < 0.001), respectively.Maximum gait speed was slower and PA lower in elderly female versus male inpatients. Minimum gait speed and step count values in this study might be minimum target values for elderly male and female Japanese cardiac inpatients.

Stratifying patients at the risk of heart failure hospitalization using existing device diagnostic thresholds

Background

Heart failure hospitalizations (HFHs) cost the US health care system ~$20 billion annually. Identifying patients at risk of HFH to enable timely intervention and prevent expensive hospitalization remains a challenge. Implantable cardioverter defibrillators (ICDs) and cardiac resynchronization devices with defibrillation capability (CRT-Ds) collect a host of diagnostic parameters that change with HF status and collectively have the potential to signal an increasing risk of HFH. These device-collected diagnostic parameters include activity, day and night heart rate, atrial tachycardia/atrial fibrillation (AT/AF) burden, mean rate during AT/AF, percent CRT pacing, number of shocks, and intrathoracic impedance. There are thresholds for these parameters that when crossed trigger a notification, referred to as device observation, which gets noted on the device report. We investigated if these existing device observations can stratify patients at varying risk of HFH.

Methods

We analyzed data from 775 patients (age: 69 ± 11 year, 68% male) with CRT-D devices followed for 13 ± 5 months with adjudicated HFHs. HFH rate was computed for increasing number of device observations. Data were analyzed by both excluding and including intrathoracic impedance. HFH risk was assessed at the time of a device interrogation session, and all the data between previous and current follow-up sessions were used to determine the HFH risk for the next 30 days.

Results

2276 follow-up sessions in 775 patients were evaluated with 42 HFHs in 37 patients. Percentage of evaluations that were followed by an HFH within the next 30 days increased with increasing number of device observations. Patients with 3 or more device observations were at 42× HFH risk compared to patients with no device observation. Even after excluding intrathoracic impedance, the remaining device parameters effectively stratified patients at HFH risk.

Conclusion

Available device observations could provide an effective method to stratify patients at varying risk of heart failure hospitalization.

Differences in daily in-hospital physical activity and geriatric nutritional risk index in older cardiac inpatients: preliminary results

BACKGROUND

Little is known about the differences in the geriatric nutritional risk index (GNRI) status in older patients and their relationship to accelerometer-derived measures of physical activity (PA) levels. We determined both differences in daily measured PA based on the GNRI and related cut-off values for PA in elderly cardiac inpatients.

METHODS

We divided 235 consecutive elderly cardiac inpatients (mean age 73.6 years, men 70.6%) into four groups by age and GNRI: older-high group, 65-74 years with high GNRI (≥92 points) (n = 111); older-low group, low GNRI (<92 points) (n = 30); very old-high group, ≥75 years with high GNRI (n = 55); and very old-low group with low GNRI (n = 39). Average step count and physical activity energy expenditure (PAEE in kcal) per day for 2 days of these inpatients were assessed by accelerometer and compared between the four groups to determine cut-off values of PA.

RESULTS

Step counts and PAEE were significantly lower in the low-GNRI versus high-GNRI groups in the older (2,742.1 vs. 4,198.1 steps, 55.4 vs. 101.3 kcal, P < 0.001), and very old (2,469.6 vs. 3,423.7 steps, 54.5 vs. 79.1 kcal, P < 0.001) cardiac inpatients. Respective cut-off values for step counts and PAEE were 3,017.6 steps/day and 69.4 kcal (P < 0.01) in the older and 2,579.4 steps/day and 58.8 kcal in the very old cardiac inpatients (P < 0.01).

CONCLUSION

Poor nutritional status, as indicated by a low GNRI, may be a useful predictor of step counts and PAEE. The cut-off values determined in this study might be target values to be attained by older cardiac inpatients.

Physical activity measured with implanted devices predicts patient outcome in chronic heart failure

BACKGROUND

Physical activity (PA) predicts cardiovascular mortality in the population at large. Less is known about its prognostic value in patients with chronic heart failure (HF).

METHODS AND RESULTS

Data from 836 patients with implantable cardioverter defibrillator without or with cardiac resynchronization therapy enrolled in the Sensitivity of the InSync Sentry OptiVol feature for the prediction of Heart Failure (SENSE-HF)(1) study and the Diagnostic Outcome Trial in Heart Failure (DOT-HF) were pooled. The devices continuously measured and stored total daily active time (single-axis accelerometer). Early PA (average daily activity over the earliest 30-day study period) was studied as a predictor of time to death or HF-related hospital admission (primary end point). Data from 781 patients were analyzed (65±10 years; 85% men; left ventricular ejection fraction, 26±7%). Older age, shorter height, ischemic cause, peripheral artery disease, atrial fibrillation, diabetes mellitus, rales, peripheral edema, higher New York Heart Association class, lower diastolic blood pressure, and no angiotensin II receptor blocker/angiotensin-converting enzyme inhibitor use were associated with reduced early PA. The primary end point occurred in 135 patients (15±7 months of follow-up). In multivariable analysis including baseline variables, early PA predicted death or HF hospitalization, with a 4% reduction in risk for each 10 minutes per day additional activity (hazard ratio [HR], 0.96; confidence interval [CI], 0.94-0.98; P=0.0002 compared with a model with the same baseline variables but without PA). PA also predicted death (HR, 0.93; CI, 0.90-0.96; P<0.0001) and HF hospitalization (HR, 0.97; CI, 0.95-0.99; P=0.011).

CONCLUSIONS

Early PA, averaged over a 30-day window early after defibrillator implantation or cardiac resynchronization therapy in patients with chronic HF, predicted death or HF hospitalization, as well as mortality and HF hospitalization separately, accounting for baseline HF severity. Clinical Trial Registration Information- URL: http://www.clinicaltrials.gov. Unique identifiers: NCT00400985, NCT00480077.

Tele-accelerometry as a novel technique for assessing functional status in patients with heart failure: feasibility, reliability and patient safety

BACKGROUND

The six-minute walk test (6MWT) is an established measure of functional exercise capacity associated with clinical prognosis in Chronic Heart Failure (CHF). The aim of this study is to evaluate the employment of tele-accelerometry for the remote assessment of 6MWT in CHF.

METHODS

155 patients were subjected to tele-accelerometry in form of monthly 6MWTs in their home surroundings. Accelerometer output included steps/6 min and walking speed. Data was directly transferred via mobile network to the Telemedicine Centre subsequent to test completion. 6MWT distance was measured by hand wheel and steps were counted with a digital hand-counter at baseline (Test 1) and at 12 months follow-up (Test 2).

RESULTS

Accelerometer accuracy was within the 99th percentile. There was a significant correlation between step count, walking speed and measured 6MWT distance (Test 1: steps: r=0.80, P<0.001; Test 2: steps: r=0.90, P<0.001 and Walking Speed Test 1: r=0.80, P<0.001; Walking Speed Test 2: r=0.86, P<0.001). The reproducibility of tele-accelerometry was within 95% margin for all performance parameters, which showed stronger associations to quality of life questionnaire (Short Form - 36) Physical Component Score (PCS) than New York Heart Association (NYHA) functional class.

CONCLUSION

Tele-accelerometry is feasible in patients with CHF and output parameters are indicative of exercise capacity. The benefit of this approach lies in its simplicity under every day circumstances by enabling routine performance testing to assess patients' functional status.

Usefulness of step counts to predict mortality in Japanese patients with heart failure

The purpose of this study was to determine both an association between mortality and physical activity (PA) objectively measured by accelerometer and cutoff values for PA in Japanese outpatients with heart failure (HF). This prospective observational study comprised 170 HF outpatients (mean age, 65.2 years; 77% men). Peak oxygen uptake (VO2) and the relation between ventilation and carbon dioxide production (VE/VCO2 slope) as indices of exercise capacity were measured during cardiopulmonary exercise testing with a cycle ergometer. PA was assessed by accelerometer-measured average step count (steps) per day for 1 week. Study endpoint was cardiovascular-related death. Over an average follow-up of 1,377.1 (median, 1,335) days, 31 cardiovascular-related deaths occurred. Patients were then divided into survivor (n = 139) and nonsurvivor (n = 31) groups. Brain natriuretic peptide level was significantly different between groups. Peak VO2 and steps were also significantly lower and VE/VCO2 slope higher in the nonsurvivors versus survivors. Univariate Cox proportional hazards analysis showed brain natriuretic peptide, peak VO2, VE/VCO2 slope, and steps to be significant prognostic indicators of survival. Multivariate analysis showed PA of ≤4,889.4 steps/day to be a strong and independent predictor of prognosis (hazard ratio: 2.28, 95% confidence interval: 1.31-6.30; p = 0.008). Kaplan-Meier curves after log-rank test showed significant prognostic difference between PA of ≤4,889.4 and >4,889.4 steps/day in the 2 groups (log-rank: 12.19; p = 0.0005). In conclusion, step count as objectively measured by accelerometer may be a prognostic indicator of mortality in Japanese outpatients with HF.

Association between mental health and physical activity in patients with chronic heart failure

PURPOSE

Poor mental health (MH) is common in chronic heart failure (CHF) patients. No studies have reported a relation between MH status and objectively measured physical activity (PA) in CHF patients. The study aim was to determine self-reported MH-related differences associated with PA and target values of PA for improved MH in CHF outpatients.

METHODS

We divided 243 CHF outpatients (mean age 57.1 years) into two groups according to MH assessed by Short Form-36 score: high-MH (≥68 points) group (n = 148) and poor-MH (<68 points) group (n = 95). Average step count (steps) and energy expenditure on PA (EE) (kcal) per day for 1 week of PA were assessed by an accelerometer and compared between groups. PA resulting in high MH was determined by the receiver-operating characteristic (ROC) analysis.

RESULTS

PA correlated positively with MH in all patients (steps: r = 0.46, p < 0.001; EE: r = 0.43, p < 0.001). After adjusting for patient characteristics, steps and EE were significantly lower in the poor-MH versus high-MH group (5020.1 ± 280.7 versus 7174.1 ± 221.5 steps, p < 0.001; 133.9 ± 10.8 versus 215.9 ± 8.4 kcal, p < 0.001). Cut-off values of 5590.8 steps and 141.1 kcal were determined as PA target values associated with improved MH.

CONCLUSIONS

Poor MH status may reduce PA. Attaining PA target values may improve MH status of CHF outpatients.