We isolated 8 genes whose expression is modulated during cardiac development. The expressions of 6 of these eight genes were modulated during the development of cardiac hypertrophy and/or during the transition to heart failure. In particular, the expression levels of the pro alpha-1 collagen, tissue type II transglutaminase, and vimentin genes were markedly increased during the transition to heart failure. Up-regulation of the pro alpha-1 collagen and vimentin genes may reflect activation of interstitial cells during the transition to heart failure. Up-regulation of the tissue type II transglutaminase gene during the transition to heart failure is intriguing, since this enzyme has been suggested to be involved in the activation of latent TGF-beta.