Heart failure is one of the leading causes of death throughout the world. During the development and deterioration processes of heart failure, cardiomyocytes undergo maladaptive hypertrophy by altering hypertrophy-related gene expression. The zinc finger protein GATA4 is one of the transcription factors involved in the regulation of cardiomyocyte hypertrophy. In response to hypertrophic stimuli such as the synaptic nervous and rennin-angiotensin systems, GATA4 forms a large complex with various functional proteins including an intrinsic histone acetyltransferase, p300, and the disruption of this complex results in the inhibition of hypertrophic responses in cardiomyocytes. While such a transcriptional signal pathway is recognized as a critical event during cardiomyocyte hypertrophy, pharmacological heart failure therapy that targets this pathway has not been established. In order to develop novel heart failure therapy targeting the pathway in cardiomyocytes, we have studied the potential of curcumin, a p300 histone acetyltransferase inhibitor, as an agent for novel heart failure therapy. In this review, we describe a recent study on the cardiac transcriptional signal pathway, especially p300/GATA4 pathway, and a novel heart failure therapy using curcumin.