Injury to the human heart, such as caused by high blood pressure and heart attack, results in the enlargement of heart muscle cells (cardiomyocyte hypertrophy) and the activation of a fetal program of cardiac gene expression. This pathological response leads to heart failure and death. On a molecular level, this pathological response is driven by enhanced expression of genes in response to the presence of proteins named transcription factors, including the MEF2 family of transcription factors.