Hemodynamic Determinants of Activity Measured by Accelerometer in Patients With Stable Heart Failure

Abstract

Objectives: This study examined the link between accelerometer recordings and cardiac pathophysiology measured with right heart cauterization at rest and with exercise in patients with HFrEF.

Background: Patient-worn accelerometers are increasingly being used in patients with heart failure with reduced ejection fraction (HFrEF) to assess activity and serve as surrogate endpoints in heart failure trials.

Methods: Physical average daily activity (PADA) and total average daily activity according to accelerometer units were assessed in 63 patients (mean age 58 ± 10 years; mean ejection fraction 26% ± 4%). Patients underwent hemodynamic exercise testing and accelerometry. Patients were divided according to PADA in PADALow and PADAHigh activity level groups based on median counts per minute of physical activity.

Results: Patients in the PADALow group were older and more frequently treated with diuretics. At rest, the PADALow group was characterized by a lower cardiac index (2.2 ± 0.4 L/min/m2 vs 2.4 ± 0.4 L/min/m2; P = 0.01) and stroke volume (70 ± 19 mL vs 81 ± 17 mL; P = 0.02) but not pulmonary capillary wedge pressure (12 ± 5 mm Hg vs 11 ± 5 mm Hg; P = 0.3). The PADALow group reached a lower cardiac index (4.8 ± 1.7 L/min/m2 vs 6.6 ± 1.7 L/min/m2; P < 0.001) but not in pulmonary capillary wedge pressure (31 ± 12 mm Hg vs 27 ± 8 mm Hg; P = 0.2) at peak exercise. The attenuated increase was associated with an attenuated increase in stroke volume (94 ± 32 mL vs 121 ± 29 mL; P < 0.001) rather than a reduced increase in heart rate (42 ± 23 beats/min vs 52 ± 21 beats/min; P = 0.07). PADA and total average daily accelerometer units were associated with patient-reported functional impairment according to the Kansas City Cardiomyopathy Questionnaire but not with New York Heart Association functional class.

Conclusions: Among stable ambulatory patients with HFrEF, lower daily activity is associated with poorer cardiac index reserve and reduced cardiac index during exercise. (Empagliflozin in Heart Failure Patients With Reduced Ejection Fraction; NCT03198585).

Keywords: HFrEF; accelerometer; exercise testing; hemodynamics; patient-centric outcome.

Conflict of interest statement

Funding Support and Author Disclosures This work was supported by the Danish Heart Foundation (grants 17-R116-A7714-22076 and 18-R124-A8573-22107), Steno Diabetes Center Odense, Denmark (grant 3363), and the A.P. Møller Foundation for the Advancement of Medical Science (grant 17-L-0339). The funders took no part in the design of the study and had no role during its execution, analyses, interpretation of the data, or decision to submit results. Dr Omar has received grants from the Danish Heart Foundation, The Steno Diabetes Center Odense, Denmark, and the A.P. Møller Foundation during the conduct of the study. Dr Jensen has received grants from the Research Council at Herlev and Gentofte University Hospital, Denmark, the Research and Innovation Foundation of the Department of Cardiology (FUHAS; formerly FUKAP), Herlev and Gentofte University Hospital, Denmark, and the A.P. Møller Foundation for the Advancement of Medical Science, Denmark, during the conduct of the study. Dr Gustafsson has received personal fees from Boehringer Ingelheim, during the conduct of the study; personal fees from Novartis; grants and personal fees from Pfizer; and personal fees from Orion Pharma Abbott, Bayer, AstraZeneca, and Carmat, outside the submitted work. Dr Borlaug has received grants from a research project grant program, from the National Institutes of Health (R01 HL128526). Dr Schou has received grants from The Capital Region of Denmark and the Danish Heart Foundation, during the conduct of the study; and personal fees and nonfinancial support from AstraZeneca; and personal fees from Novo Nordisk and Boehringer Ingelheim, outside the submitted work. Dr Møller has received grants and personal fees from Abiomed; and personal fees from Novartis and Orion Pharma, outside the submitted work. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.

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