Footnotes

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

• Competing interests CMO interprets echocardiographic studies as part of her clinical practice. She is the author/editor of medical textbooks about echocardiography and valvular heart disease.

• Patient consent Not required.

• Provenance and peer review Commissioned; internally peer reviewed.