Implantable cardioverter-defibrillator (ICDs), cardiac resynchronization (CRT) and combination (CRT-D) therapy have become an integral part of the management of patients with heart failure with reduced ejection fraction (HFrEF). ICDs treat ventricular arrhythmia and CRTs improve left ventricular systolic function by resynchronizing ventricular contraction. Device therapies (ICD, CRT-D), have been shown to reduce all-cause mortality, including sudden cardiac death. Hospitalizations are reduced with CRT and CRT-D therapy. Major device related complications include device infection, inappropriate shocks, lead malfunction and complications related to extraction of devices. Improvements in device design and implantation have included progressive miniaturization and increasing battery life of the device, optimization of response to CRT, and minimizing inappropriate device therapy. Additionally, better definition of the population with the greatest benefit is an area of active research.