Footnotes

• Contributors Both authors have contributed equally to this manuscript.

• 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 SDP reports research grant support from Bristol-Myers Squibb, Pfizer, Janssen Pharmaceuticals, Boston Scientific, Gilead, and the Food and Drug Administration; Consultant/Advisory Board from Bristol-Myers Squibb, Pfizer, Janssen Pharmaceuticals, Boston Scientific, and Medtronic. RDL reports institutional research grant and consulting fees from Bristol-Myers Squibb; institutional research grant from GlaxoSmithKline; consulting fees from Bayer, Boehringer Ingelheim, Pfizer, Merck, Portola.

• Provenance and peer review Commissioned; internally peer reviewed.