LAUSR

In this issue van der Bijl et al. demonstrate that evidence of echocardiographic reverse remodelling after cardiac resynchronization therapy (CRT) was substantially stronger among patients with left bundle branch block (LBBB) compared with patients with non-LBBB morphology. The findings were similar when comparing patients with a QRS width of ≥150 ms vs. <150 ms with greater volume reductions and improvements in ejection fraction in the patients with the wider QRS complexes.1 These are encouraging findings for clinicians and further confirm and extend our established knowledge concerning selection of appropriate patients for CRT. The interpretation of the available data accumulated during the last two decades is consistent: CRT works best in patients with LBBB morphology combined with a wide QRS complex. The favourable response includes both echocardiographic indices of functional improvement (reverse remodelling)2,3 and improvement in terms of major clinical outcomes.4–6 This knowledge was established by a large number of randomized clinical trials, and subgroupand meta-analyses, and forms the basis for the strong indications for CRT in the 2016 ESC guidelines,7 which emphasize the importance of QRS morphology and duration in the selection of patients. The present, retrospective, observational study was performed on a large, ‘real world’ clinical registry at an institution with recognized expertise in echocardiography as well as long-term experience in CRT. The cohort consisted of 1467 patients with heart failure and a wide range of QRS durations and morphologies.