Tag Archives: pressure-volume loop

Obscure origin of the ejection fraction metric Only rarely have investigators revealed the origins of the popular metric called ejection fraction (EF), while, for example, referring to William Harvey or to a psychiatrist.1 Recently, a position paper reported that in 1918 MacKenzie ‘measured’ EF using heart rate and pulse pressure.2 However, one thing is clear: a rigorously documented foundation is absent.3 Fact is that more than a century ago Bardeen directly calculated the ratio of left ventricular (LV) stroke volume (SV) and end-diastolic volume (EDV).4 Indeed, there is no single published paper that explains, in full detail, what the e