Heart failure is a progressive and fatal disease process. Arrhythmias and progressive cardiac dysfunction account for most of the morbidity and mortality in patients with heart failure. In general, the physiologic mechanisms responsible for progressive myocyte dysfunction, remodeling, and arrhythmias involve signaling mechanisms that alter myocardial gene expression. These changes in gene expression are complex and involve contractile proteins, ion channels, Ca++ handling, apoptosis, cell metabolism, the extracellular matrix, signal transduction pathways, and growth factors.