Cardiac resynchronization therapy and device-based cardiac contractility modulation

Heart Failure (HF) is a global epidemic characterized by significant morbidity and mortality. Cardiac resynchronization therapy (CRT) and cardiac contractility modulation (CCM) are two device-based therapies currently available for HF patients. CRT enables favorable remodeling and improves quality of life (QOL) and mortality in HF patients with systolic dysfunction and ventricular dyssynchrony. A significant minority of patients does not benefit from CRT, and considerable research efforts are dedicated to improving CRT response. CCM is an emerging technology which improves left ventricular energy dynamics and remodeling by delivering non-excitatory electrical signals during the absolute refractory period. Initial studies of CCM have shown improvements in QOL and functional capacity in HF patients with systolic dysfunction and intact ventricular synchrony. Larger studies with longer follow-up are required before CCM is adopted into routine practice. This chapter will review current applications of CRT and CCM as well as describe future directions and challenges.