Tag Archives: phenotyping

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

Figure 1A. Volume domain representation of data sets referring to acute myocardial infarction patients. End-systolic volume (ESV) is plotted against end-diastolic volume (EDV). The dark blue line indicates a trajectory with a constant value for ejection fraction (EF), in this case 45%. Four patients satisfy this condition, but can be distinguished by considering the distance from the origin to each individual point. This distance is termed the companion to EF, and denoted as EFC. An example (pink-arrowed bar) is shown for the patient with the smallest ventricle having EF=45%. Four patients (marked by the coloured dotted lines referring to th