Key result
The historical development and physiological basis of left ventricular ejection fraction measurement reveal significant limitations in its ability to accurately reflect true systolic function.
This editorial provides a historical perspective on the origins and physiological limitations of left ventricular ejection fraction as a measure of systolic function.
he measurement of left ventricular ejection fraction (LVEF) was first proposed by Stuart Bartle, a young cardiovascular researcher at University of Virginia in the early 1960s. 1 Based on images derived from contrast cineangiography, he coined the term ejected fraction to describe the ratio of stroke volume to LV end-diastolic volume (LVEDV).At the time, no one thought that the calculation of LVEF represented a major intellectual achievement, either conceptually or physiologically.As I can personally affirm, 2 Bartle himself dismissed the usefulness of the concept entirely, as evidenced by his subsequent decision to spurn cardiology and embrace psychiatry as his primary career path, becoming a highly distinguished psychotherapist and humanitarian.2 EF DOES NOT REFLECT SYSTOLIC FUNCTIONThe circulation takes great pains to maintain cardiac output and stroke volume.Therefore, if stroke volume is held constant, the ratio of stroke volume to LVEDV (the LVEF) is essentially the inverse of the LVEDV.3 In the heyday of contrast ventriculography, the measurement of LVEDV was based on exceedingly tedious planimetry.When noninvasive imaging emerged as a tool for the assessment of LV structure and function, a single dimension on M-mode echocardiography provided the basis for the most common estimate of LVEDV, but a single beam-based estimate of LVEDV was based on many unverifiable assumptions about the shape of the left ventricle, especially in an era when segmental myocardial infarction represented the principal driver of LV dysfunction.Furthermore, depending on the angle of the transducer, the measurement of LV end-diastolic dimension could vary wildly, and because the value was cubed to yield volume, the errors in estimating LVEDV could be magnified exponentially.How could this dilemma be solved?For more than a decade, radionuclide ventriculography allowed for the easy collection of the number of tracer counts in end systole and end diastole, and, thus, allowed for the estimation of LVEF, without the need for a validated measure of LVEDV. 4 The dominance of radionuclide ventriculography (before the clinical availability of 2-dimensional Doppler echocardiography) solidified the impression that the measurement of LVEF had meaning.
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Milton Packer (2024) conducted an editorial in Heart Failure. The historical development and physiological basis of left ventricular ejection fraction measurement reveal significant limitations in its ability to accurately reflect true systolic function.
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