EDITORIAL Heart rates in cardiac resynchronization: the art of optimal device programming

This editorial refers to ‘Acute haemodynamic effects of increase in paced heart rate in heart failure patients recorded with an implantable haemodynamic monitor’ by M. Ståhlberg et al., on page 237. Cardiac resynchronization therapy (CRT) has become the stan-dard therapy for patients with decreased systolic left ventricular (LV) function with the indication extending most recently also the less symptomatic patients.1 Implantation rates in Europe have steadily increased with a clear difference between countries.2 Objective response rates with significant reverse LV remodelling have remained at 50–70 % depending on the definition. Reverse remodelling, however, is the pre-requisite for decreasing hard clini-cal endpoints.3 Optimal delivery of CRT rests on three legs: (i) patient selection, (ii) optimal implantation, and (iii) optimal device programming. Although the first and, to lesser extent, th