Excerpt

During the last decade, since its introduction, cardiac resynchronisation therapy (CRT) has become a mainstay therapy in a selected group of patients with end-stage heart failure and a left bundle branch block (LBBB) on the ECG. While the evidence for the beneficial effects of CRT in large populations has been established unequivocally,1 it is the response in the individual which has grasped the interest of most due to the relatively large number of nonresponders. In up to 40% of patients fulfilling the current guideline criteria for CRT no clinical improvement and/or echocardiographical remodelling is observed during follow-up. Many studies have been conducted to distinguish the responders from the nonresponders in order to improve the selection of patients who would benefit from this relatively expensive treatment. …