We have found that the balance between expression levels of slow oxidative skeletal muscle fiber MHC isoform MYH7 and fast glycolytic isoform MYH1 was notably downregulated in HF muscle (Figure 1(b)), along with the downregulation of the expression of Pgc1a (Figure 1(c)) that indicates an impairment in the regulation of the transcriptional program for mitochondrial biogenesis and oxidative metabolism in HF [23]. Here, MYH1 is linked to hydrops fetalis.