Nature Reviews Cardiology (2019) https://doi.org/10.1038/s41569-019-0224-z Published online 27 June 2019

In the version of this article initially published online, the four images of electrograms in Figure 2 were incorrectly labelled. From left to right, the correct labels are: Proximal to LBB delay, Non-selective HBP without correction of LBBB, Selective HBP with correction of LBBB and Distal to LBB delay. This error has been corrected for the HTML, PDF and print versions of the article.