Footnotes

• Contributors KK is the sole contributor.

• Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

• Competing interests None declared.

• Provenance and peer review Commissioned; externally peer reviewed.

• Author note The Corresponding Author has the right to grant and does grant, an exclusive license on a worldwide basis to the BMJ Publishing Group and its Licensees to permit this article to be published in Heart editions and any other BMJPGL products to exploit all subsidiary rights.