A novel, personalised home-based physical activity intervention for chronic heart failure : exploring feasibility, effectiveness and patient experiences

Abstract

Heart failure (HF) is a clinical syndrome associated with reduced cardiac output at rest and/or in response to stress. Physical activity plays an important role in reducing cardiovascular morbidity and mortality. Patients with chronic heart failure demonstrate reduced physical activity levels. Exercise based cardiac rehabilitation programmes are safe and recommended to improve symptoms and outcomes in HF. Available data suggests that less than 10% of patients with HF in the UK are referred for cardiac rehabilitation. This is secondary to lack of resources and direct exclusion of HF rehabilitation from local commissioning agreements. A personalised home-based physical activity intervention may hold great potential to improve patient outcomes and clinical practice. This thesis firstly investigates non-invasive methods for evaluation of cardiac function (cardiac output) at rest and in response to cardiopulmonary exercise stress testing. Secondly, is explores the feasibility and physiological effects of a novel, personalised home-based physical activity intervention in HF patients (Active-at-Home-HF), and qualitatively explores barriers and facilitators to uptake and continued participation from a patient perspective. The major findings and conclusions of the thesis suggest that i) Bioreactance and inert gas rebreathing methods show acceptable levels of agreement for estimating cardiac output at higher levels of metabolic demand. However, they cannot be used interchangeably due to strong disparity in results at rest and low-to-moderate exercise intensity; ii) Inert gas rebreathing method demonstrates acceptable level of test-retest reproducibility for estimating cardiac output at rest and during cardiopulmonary exercise testing at higher metabolic demands; iii) Active-at-Home-HF intervention is safe, feasible and acceptable for patients with chronic HF. It leads to increased daily physical activity levels and may improve quality of life and exercise tolerance; and iv) Lastly, the qualitative study emphasizes the importance of clinicians who advocate physical activity as a management option for heart failure, personalised support to increase and maintain levels of physical activity and that heart failure patients should seek social support from friends and family.