Disclosures: RJH has received educational grants from Medtronic and from Biosense Webster in relation to a different study, VM has received speaker fees and travel support from Biosense Webster, TW has received research funding support from St. Jude Medical/Abbott, AC has received educational grants from Boston and speaker fees from St. Jude Medical/Abbott, PDL is supported by the NIHR UCLH/UCL and Barts Biomedical Research Centres, and has received speaker fees, research and educational grants from Boston Scientific and research grants from St. Jude Medical/Abbott and Medtronic. The other authors have no relevant disclosures.