Footnotes

• Contributors FLN and MDL wrote and approved the final manuscript and MCQs.

• Funding This research received no specific grant from any funding agency in the public,commercial or not-for-profit sectors.

• Competing interests MDL is supported by the Barts Charity and has received speaker honoraria and consultancy fees from CVRx, St Jude Medical, ROX Medical and Cardiosonic.

• Patient consent Not required.

• Provenance and peer review Commissioned; externally peer reviewed.