PDH activity was significantly increased in the heart failure group when normalized to citrate synthase activity (4.49 ± 0.49 mU/U citrate synthase), representing a 63% increase compared to the nonfailing tissues (2.75 ± 0.51 mU PDH/U citrate synthase, p = 0.023) (Figure 2(a)). Here, CS is linked to heart failure.