Objective To evaluate the correlation of the maximum six minutes of daily activity (M6min) with standard measures of functional capacity among older adults with heart failure (HF) in comparison to younger subjects and its prognostic utility. Design Prospective, cohort study. Setting Tertiary care, academic HF center. Participants Sixty, ambulatory, adults, NYHA Class I-III, stratified into young (51±10 years) and older cohorts (77±8 years). Intervention Continuous actigraphy monitoring on the non-dominant wrist. Measurements Correlation between M6Min and measures of functional capacity (6 minute walk distance; 6MWT) and with peak VO2 by cardiopulmonary exercise testing in a subset. Survival analysis was employed to evaluate the association of M6Min with adverse events. Results Compliance with actigraphy was high (90%) and did not differ by age. The correlation between M6min and 6MWT was higher in subjects ≥ 65 years of age than those <65 years of age (r=0.702, p=0.0002 vs. r=0.490, p=0.002). M6min was also significantly associated with peak VO2 (r=0.612, p=0.006). During the study, 26 events occurred (2 deaths, 10 hospitalizations, 8 emergency room visits and 6 intercurrent illnesses). The M6min was significantly associated with subsequent events (Hazard ratio of 2.728; 95% CI: 1.099–6.775, p=0.031) independent of age, gender, ejection fraction, NYHA class, brain natriuretic peptide, and 6MWT. Conclusions The high compliance with actigraphy and association with standard measures of functional capacity and independent association with subsequent morbid events suggests that it may be a useful for monitoring older adults with heart failure.

Background Anergia (lack of energy) is a newly delineated, criterion-based geriatric syndrome. Since heart failure (HF) is a common chronic condition among older adults and a since a cardinal symptom of HF is reduced energy, we characterized the degree of anergia in subjects with HF and evaluated its relevance to disease severity, functional performance and quality of life. Methods Prospective 3-month cohort study among a convenience sample of 61 subjects (61±15 years, 48% women, EF 41±16%) with NYHA Class I-III HF were studied. The criterion for anergia was based upon the major criterion “sits around for lack of energy” and any two of six minor criteria. Principal measures in addition to demographic and clinical characteristics included functional performance (NYHA class, 6 minute walk, cardiopulmonary exercise testing), plasma B-type natriuretic peptide and quality of life (SF-12 and Minnesota Living with Heart Failure Questionnaire). To evaluate the relevance of anergia to daily function, each subject wore an actigraph, a watch-like wrist device that continuously and automatically monitors patient activity levels and energy expenditure, for 3 months. Results Anergia was prevalent in 39% of this population. Anergia was associated with decrements in functional capacity (higher NYHA class and lower six minute walk distance) as well as reduction in quality of life but was not associated with ejection fraction. Actigraphy data demonstrated that HF subjects with anergia spent significantly less time performing moderate physical activity and the peak activity counts per day were significantly lower than HF subjects without anergia. Additionally, the amplitude of circadian rhythm was lower, suggesting altered sleep and activity patterns in HF subjects with anergia compared to those without anergia. Over the 3 months of follow-up, there was a significant association between anergia and inter-current hospitalization. Conclusions Anergia is significantly associated with several of the cardinal domains of heart failure. Its presence is associated with demonstrable differences in both physical activity and circadian rhythm as measured by actigraphy and an increased risk of hospitalizations. Accordingly, anergia may be a target for intervention among heart failure subjects.

An algorithm has been developed to automatically construct individual models of normal activity within a home using motion sensor data. Alerts can be generated when a period of inactivity exceeds a normal length for a particular residence. Alerting frequency has been optimized on a total of 650 days of real data from four homes of seniors who live independently. Results suggest that an inexpensive system that does not require the occupant to push any buttons or wear any devices could nonetheless alert within hours if a senior is unusually inactive. Further, such algorithms may facilitate widespread deployment of smart home technology to persons with different behavior patterns and home layouts by using automatic learning in place of potentially tedious manual configuration.