Marcus Carlsson investigates cardiac pumping using magnetic resonance imaging. His 2007 primary study measured longitudinal atrioventricular-plane displacement and related it to stroke volume in twelve controls, twelve elite triathletes and twelve patients with dilated cardiomyopathy.[ref]
The study combined a longitudinal displacement with a short-axis area to estimate the longitudinal contribution to ejected volume.[ref]
Atrioventricular plane displacement is the major contributor to left ventricular pumping in healthy adults, athletes, and patients with dilated cardiomyopathy by Marcus Carlsson and others. Abstract, calculation from mean epicardial area and displacement
A shorter displacement need not imply a proportionally smaller contribution when the chamber's transverse dimensions differ.An original constant-area illustration givesWith stipulated and cm, the modeled contribution is 40 mL. Doubling area to while halving displacement to 0.5 cm gives the same 40 mL. If total stroke volume is 80 mL in both examples, both longitudinal fractions are one half. These are geometric examples, not group values from the study.
This explains why comparing displacement alone and comparing its contribution to stroke volume are different questions. The experimental paper supplies actual images and a specified geometric estimator, while the toy model isolates the multiplication responsible for that distinction. Neither a displacement nor its volume fraction alone determines every aspect of ventricular function; ejection fraction also requires the corresponding chamber volume.
Marcus Carlsson, named portrait linked from his Karolinska Institutet profile
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