Figure 4.
31Phosphorus magnetic resonance spectroscopy (31P-MRS)-derived phosphocreatine (PCr) recovery curves in a control subject from the current study (open circles), a patient with heart failure with preserved ejection fraction (HFpEF) from the current study (inverted triangles), and a previously tested mitochondrial myopathy patient (upright triangle). Subjects were tested using a similar protocol during which the quadriceps muscle was imaged immediately after achieving a pre-defined exercise-induced metabolic state. Post-exertion, HFpEF and mitochondrial myopathy patients have diminished PCr stores with delayed regeneration, suggesting that impaired skeletal muscle oxidative metabolism in HFpEF may be the explanation for the diminished oxygen uptake in this group.