Buchanan C, Tran T, Riordan M, et al. - Researchers sought to inscribe individual components of VO₂(cardiac output [Qc] and (A-V)O₂ difference) at rest and during submaximal and peak exercise among CF-LVAD patients. Invasive cardiopulmonary exercise testing on a stationary upright cycle ergometer was performed on 13 CF-LVAD participants (56±12 yrs, 12 male) and 9 healthy controls 42±12 yrs, 7 male). They performed collection of hemodynamic data and gas-exchange parameters at rest, two submaximal levels of exercise below the ventilatory threshold, and peak workload. Baseline hemodynamics were determined via performing Swan-Ganz catheterization. Qc was then calculated at each stage of exercise using a conductance catheter. Using indirect calorimetry, recording of VO₂ on a breath-by-breath basis was done. Continuous monitoring of blood pressure was done by arterial line. The (A-V)O₂ difference was calculated at each stage of exercise for assessing musculoskeletal performance. Severely reduced peak VO₂ was observed among CF-LVAD participants vs healthy controls. Due to impairments in contractile reserve, a greater (A-V)O₂ difference was observed in CF-LVAD participants vs healthy individuals when exercising at similar workloads.