A hallmark of pathological hypertrophy and HF is the reactivation of a set of fetal cardiac genes, including the hypertrophic gene markers ANF, BNP, Myh6, and Myh7, and the fibrosis markers Col1a2 and Col3a1. At baseline level, the expression of fetal cardiac genes was not altered in miR‐574−/− mice (Appendix Fig S1E). This evidence concerns the gene COL3A1 and hydrops fetalis.