Cardiac Resynchronization Therapy (CRT) is a medical procedure which has revolutionized treatment for patients with heart failure. The procedure was first described in 1994. Its benefit relies on the fact that many patients with heart failure have uncoordinated contraction of the left ventricle which results from abnormal electrical activation patterns. This gives rise to inefficient mechanical function. CRT involves transvenous placement of an electrical pacing lead in a coronary vein to the surface of the left ventricle. This is connected to a cardiac pacemaker in order to recoordinate the hearts contractile function. This represents a huge breakthrough in medicine and biomedical science and is the focus of great interest in research and development of new technologies. The purpose of this review is to illustrate recent inventions patented in this rapidly evolving field. We will focus on device technology, lead delivery systems and methods of optimising pacemaker function. We will also discuss current and future developments in cardiac resynchronization therapy.