Neonatal murine cardiomyocytes (NMCMs) treated with anti-Hdac1 and anti-Hdac2 siRNAs to predict the effects of HDACs on action potential duration (APD) and the mRNA expression of ion channels show that a slight reduction in the LV ejection fraction increases ventricular effective refractory periods and that prolonged corrected QT interval (QTc) intervals are characteristic of early heart failure. This evidence concerns the gene HDAC2 and heart failure.