SESSION TITLE: 21st Century Technology
SESSION TYPE: Original Investigation Slide
PRESENTED ON: Wednesday, October 28, 2015 at 08:45 AM - 10:00 AM
PURPOSE: Exercise capacity can be used to determine functional status, prognosis, and for adjustment of therapeutics in heart failure (HF) patients. There are a variety of methods to assess exercise capacity, including six-minute walk (6MW) test, peak VO2, and submaximal exercise measurements. We sought to understand the relationships between exercise modalities and in particular understand the value of patient home collected pedometer step measurement in heart failure patients.
METHODS: To investigate the feasibility of pedometer measured activity and to correlate with known prognostic variables, we enrolled 23 patients with Stage C HF. The patients (15 men, 8 women) aged 37-85 (69 mean) years, NYHA Functional Class 1-3 (2.1) wore a pedometer for 3 days to record home activity; the 3 day results were averaged. Then a 6MW test with simultaneous measurement of oxygen consumption variables was performed.
RESULTS: The mean 6MW distance was 988.9ft, while the mean daily pedometer steps were 2226. The mean peak VO2 was 9.26 ml/kg/min. The data confirms a relationship between functional class and pedometer steps (R=0.62, p=0.002), pedometer steps and 6MW (R=0.68, p=0.0005) and peak VO2 and 6MW distance (multiple R=0.73, p=0.0001). While both relationships between home measured pedometer steps and peak VO2 and VE/VCO2 were suggestive (both R=0.43, p=0.04 the reationships were not as statistically significant..
CONCLUSIONS: We suggest that home measured pedometer steps correlate with other key meausrements of functional status (NYHA FC and 6MW distances) in heart failure patients, and may serve as suitable surrogate markers of potent exercise prognostic indices. However, they may not replace oxygen consumption variables. The pedometer may be further used to motivate HF patients to increase activity and be used as early home predictors of subtle changes in clinical status.
CLINICAL IMPLICATIONS: Average daily steps as measured by a home pedometer provides important surrogate exercise information for heart failure patients. Step measurement correlates well with functional class, 6 minute walk distance but not as well with peak VO2 or VE/VCO2. With increased availability of individual personal health data collection, step measurement might be used as an early warning of sublte changes in clinical status and to better guide heart failure therapies and decisions.
DISCLOSURE: The following authors have nothing to disclose: Marc Silver
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