Abstract 18347: Patterns of Physical Activity and Survival Following CRT-D Implantation: The ALTITUDE Activity Study
Background: Device-detected physical activity predicts survival following ICD implantation. CRT is implanted in part to improve the functional status of patients with CHF. Patterns of activity changes following CRT implantation, and their relationship to survival, have not been described.
Methods: CRT-D patients in the Boston Scientific ALTITUDE registry from 2008-2012 with activity measurements through 210 days were eligible. Remote monitoring data were used to calculate physical activity differences (mean minutes/day) between baseline post-implant (first 3-10d); short-term (30-60 days) and 6 months (180-210 days). The relationship between activity changes between baseline and 6 months by quintile and survival were modeled using Cox regression.
Results: Among 36,699 patients (mean age 70.8 + 10.9, 29.5% women), mean activity was 68.9 + 48.9 min/day at baseline, 97.9+ 60.7 min/day at 30-60 days, and 100.0+ 64.9 min/day at 6 months. Mean paired differences between baseline and 6 month activity was 31.1 min/day (95% CI, 30.6-31.6, P<0.0001). However, mean paired differences between 30-60 days and 6 months was only 2.2 min/day (95% CI 1.8-2.5, P<0.0001). Unadjusted survival from 6-months post-CRT-D implant in the highest vs lowest quintile of activity change (baseline - 6 months) was 96.8% vs 83.9% at 1 year, and 87.6% vs 62.1% at 3 years (log-rank P <0.0001 for both comparisons). After adjustment for age, gender, and baseline activity, change in activity at 6 months strongly predicted survival (HR 1.51 per 30 min change, 95% CI 1.48-1.55, two-sided Wald test P <0.0001).
Conclusion: This large, nationwide sample of CRT-D recipients suggests that physical activity following implantation increases an average of over 30 min/day, with most of the change manifest in the 2nd month of therapy. Adjusted survival is markedly improved in patients who demonstrate improved activity levels.
Author Disclosures: D. Kramer: Research Grant; Significant; NIH. Other Research Support; Modest; John A. Hartford Foundation. P.W. Jones: Employment; Significant; Boston Scientific. T. Rogers: None. S.L. Mitchell: Research Grant; Significant; NIH. M.R. Reynolds: Consultant/Advisory Board; Modest; Medtronic.
- © 2015 by American Heart Association, Inc.