Genes differentially expressed between normal control and congestive HF (CHF) dogs included P3H1, P3H2, P3H4, P4HA2, PLOD1 and PLOD3, which belong to the 2-oxoglutarate-dependent dioxygenases (2OGD) superfamily that stabilizes collagen during fibrosis. Here, P3H4 is linked to congestive heart failure.