Cardiac contractility modulating (CCM) signals are nonexcitatory signals applied during the absolute refractory period and have been shown to enhance the strength of left ventricular contraction in studies performed in animals and humans with heart failure. In patients with congestive heart failure, improvement of exercise tolerance and quality of life have been shown. Recent studies from myocardial biopsies demonstrate that CCM treatment normalizes expression of many genes that are abnormally expressed in heart failure, including proteins involved with calcium cycling. These findings suggest that CCM might be an alternative or even additional electrical treatment option for patients with heart failure and normal QRS duration delivered by a pacemaker, e.g., a rechargeable device without any antibradycardiac or antitachycardiac function.