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Physical Activity in Association with Prognostic Determinants Across Heart Failure Continuum
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- Author / Creator
- Yavari, Milad
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Heart Failure (HF) is a complex syndrome that greatly contributes to declining physical function in older adults and causes a substantial economic burden for health care systems. Older adults at risk of developing HF typically have other comorbidities. In addition, patients with HF often experience periods of exacerbations as the disease progresses. Despite recent improvements in medical treatments, the prognosis of older adults diagnosed with HF is poor and their quality of life deteriorates quickly. Near half of the patients with HF have preserved ejection fraction (HFPEF) with an increasing prevalence compared to those with HF and reduced ejection fraction (HFREF). Although the underlying mechanisms to develop the two phenotypes are different, the reduced aerobic capacity is one of the important clinical features in both. While historically exercise training has been prescribed to improve exercise intolerance in patients with HF, there is no consensus regarding the characteristics of an effective training program. Moreover, the low rate of referrals to some exercise-based rehabilitation programs and poor compliance may not bode well for a long-term behavior change. Some investigators suggest daily physical activity (PA) as a more practical substitute in older adults with HF.
The role of PA in promoting cardiovascular health and improving symptoms, function and health-related quality of life in patients at risk of with HF (At-risk) has been understudied. In addition, for many HF patients daily PA may be closely linked to clinical prognosis. With the advancements of technology reliable devices capable of monitoring PA in a broader range of intensities are available now. However, the objectively measured PA in the two phenotypes of HF and those at risk of HF compared to healthy controls are unknown. Therefore, the purpose of the first study was to assess daily PA across the HF continuum. The findings showed that patients with HFPEF had the lowest volume of PA across the four groups. Also, patients with HFREF spent a higher amount of time in bouts of moderate-vigorous PA than patients with HFPEF. In addition, our results suggested the steps/day as the most robust measure in evaluating PA in this population.
The second and third studies in this thesis aimed not only to investigate the association between daily PA (i.e., steps/day) and prognostic determinants in patients with HF but also to assess if these associations are different across the HF continuum. Evaluating the associations between the markers of PA, aortic distensibility (AD), and myocardial stress biomarkers could also help in the development of pathways leading to earlier diagnosis, more precise classifications, and a better prognosis for patients with HF.
The results of the second study showed that the association between steps/day and AD may not be similar across the continuum of HF. The findings showed there was a direct relationship, such that a higher range of steps/day was associated with a higher AD, but only in our small HFREF group. The findings of the third study also indicated the association between steps/day and BNP or NT-proBNP were not comparable across groups, from healthy controls, to those At-risk and with HFPEF. In fact, the association between steps/day and biomarkers were more prominent in the At-risk group compared to HFPEF group.
In summary, the findings of three studies in this thesis suggest that the majority of patients at risk or with HF have a sedentary lifestyle. In addition, the daily PA performed by the majority of patients with HF might not reach the minimum volume required to improve AD or reduce biomarkers. The information provided by the objective assessment of PA could be used as an important tool to establish realistic rehabilitation goals and design individualized programs. Although the ultimate goal in this population should be to meet the current recommendations, for a majority of patients it appears to be achievable only through a tailored increase in the volume of PA. In addition, the association between a single marker of PA such as steps/day and important prognostic determinant of HF underscores the importance of regular assessment of this behavior. Despite the different mechanisms by which PA benefits individuals across HF continuum, it is critical to recognize risk factors associated with a sedentary lifestyle and proper strategies to tackle this issue. -
- Graduation date
- Fall 2020
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- Type of Item
- Thesis
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- Degree
- Doctor of Philosophy
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- License
- Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.