Kinematic parameters related to functional capacity, fatigue, and breathlessness during the 6-min walk test in older adults with heart failure with preserved ejection fraction

Aims This paper aims to assess kinematic parameters related to functional capacity, fatigue, and breathlessness during the 6-min walk test (6MWT) in patients with heart failure with preserved ejection fraction (HFpEF). Methods and results A cross-sectional study was conducted in which adults 70 years or older with HFpEF were voluntarily recruited between April 2019 and March 2020. An inertial sensor was placed at the L3-L4 level and another on the sternum to assess kinematic parameters. The 6MWT was divided into two 3-min phases. Leg fatigue and breathlessness, assessed by the Borg scale, the heart rate (HR), and the oxygen saturation (SpO(2)), were measured at the beginning and the end of the 6MWT. The difference in kinematic parameters between the 6MWT two 3-min phases was also calculated. Bivariate Pearson correlations and subsequent multivariate linear regression analysis were performed. Seventy older adults with HFpEF (mean = 80.74 years old) were included. Kinematic parameters explained 81.00% of the functional capacity, 45.50% of the leg fatigue and 66.10% of the breathlessness variance. Moreover, kinematic parameters could explain 30.90% of the SpO(2) variance at the end of the 6MWT. Kinematic parameters also explained 33.10% of the SpO(2) difference between the beginning and end of 6MWT. Kinematic parameters explained neither the HR variance at the end of 6MWT nor the HR difference between the beginning and end. Conclusion Gait kinematics from L3-L4 and sternum explain a part of the variance in subjective outcomes, assessed by the Borg scale, and objective outcomes such as functional capacity and SpO(2). The kinematic assessment allows clinicians to quantify fatigue and breathlessness through objective parameters related to the patient's functional capacity. Registration ClinicalTrials.gov NCT03909919.