Mechanisms Determining VO2peak During Single Leg Knee‐Extension Exercise in Heart Failure with Preserved Ejection Fraction Patients: Peripheral vs. Central Phenotypes

摘要: Background Heart failure with preserved ejection fraction (HFpEF) is characterized by exercise intolerance, including a reduced maximal aerobic capacity that affects all aspects of daily living. The mechanisms responsible for the decreased exercise tolerance in HFpEF are incompletely understood. Our research group has characterized two unique HFpEF phenotypes based on cardiac output reserve relative to exercise metabolic work: those with either a “central” (Type A) or “peripheral” (Type B) limitation to exercise. We sought to investigate the peripheral limitations to exercise in these 2 phenotypes using single‐leg knee extension (SLKE) exercise, a modality that reduces the central limitations to exercise. Specifically, we tested the hypothesis that patients with the Type B phenotype would have lower leg VO2peak secondary to insufficient oxygen extraction (i.e., lower ∆a‐vO2diff) when compared to patients with …