EDITORIAL COMMENT Optimisation of cardiac resynchronisation therapy during exercise

# The Author(s) 2013. This article is published with open access at Springerlink.com The benefits of cardiac resynchronisation therapy (CRT) in selected cohorts with systolic dysfunction and congestive heart failure are well established [1–3]. CRT reduces heart failure hospitalisations, decreases mortality, and improves the quality of life and cardiac function, described as left ventric-ular (LV) reverse remodelling. CRT improves inter-, intra- and atrio-ventricular dyssynchrony. It is important to stress that there is only a moderate correlation between clinical and echocardiographic response; i.e. patients with improvement in their clinical status might not always show significant reverse remodelling. Nevertheless, the number of patients who do not respond to this therapy remain as high as 30 % to 40 %. The reasons for not responding to CRT are probably complex and multifactorial. Patient selection, accurate assess