Cardiac resynchronization therapy decreases mortality and rehospitalization for heart failure. However, around 30% of patients do not respond to this therapy. The paper analyses factors, with a possible impact on the response to this therapy. It is a left ventricular lead proximity to the left ventricle segment with the latest activity, presence and size of postinfarction scar and a percentage of fully captured paced beats. Methods of optimalization of these factors are described as well as circumstances, under which some patients should be indicated for cardiosurgical lead implantation or if a cardiac resynchronization therapy should be ommited.