In vivo evidence confirms intramuscular concentration of ADP are higher and Phosphocreatine (PCr) and pH are lower for given work rates in patients with CHF,12, 13 which could explain our transcriptome findings that AMPD3 expression is increased to compensate under metabolic stress where ATP is low (Figures 1, 2, 3).12, 13. Here, AMPD3 is linked to congestive heart failure.