Author + information
- Bas M. van Dalen, MD, PhD∗ (, )
- Sanne M. Snelder, MD and
- Marcel L. Geleijnse, MD, PhD
- ↵∗Department of Cardiology, The Thoraxcenter, Erasmus University Medical Center, ‘s-Gravendijkwal 230, Room Bd412, 3015 CE Rotterdam, the Netherlands
We read with great interest the study by Stokke et al. (1) in which a mathematical analysis was used to show the relationship between left ventricular ejection fraction (LVEF) and global longitudinal and circumferential strain, wall thickness, and short-axis diameter in 80 patients with heterogeneous heart disease and 20 healthy controls. Although the important findings of Stokke et al. (1) add to our understanding of LV function, the conclusion, that the paradox of reduced myocardial shortening in the presence of preserved EF is explained through geometric factors, erroneously ignores the important role of LV twist.
Leonardo Da Vinci is considered to be the first to describe the rotational motion of the LV, which was later compared to the wringing of a linen cloth to squeeze out the water by Richard Lower in 1669. However, it lasted until recently before LV twist was described in more detail. LV twist originates from the dynamic interaction between oppositely wound subepicardial and subendocardial myocardial fiber helices. LV twist plays a pivotal role in the mechanical efficiency of the heart, making it possible that only 15% fiber shortening results in a 60% reduction in LV volume (2).
Because the direction of LV twist is governed by the subepicardial fiber helix, mainly owing to the longer arm of movement, loss of contraction of the counteracting subendocardial fibers will lead to increased LV twist (3,4). Longitudinally oriented subendocardial fibers and circumferentially oriented midwall fibers are more vulnerable to wall stress in patients with cardiac disease than the subepicardial fibers governing LV twist. Therefore, decreased longitudinal and circumferential strain may be compensated by increased LV twist, without a need for geometric modifications. In future models for analysis of LV function the vital role of LV twist should be included.
Please note: The authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- 2018 American College of Cardiology Foundation
- Stokke T.M.,
- Hasselberg N.E.,
- Smedsrud M.K.,
- et al.
- Sengupta P.P.,
- Tajik A.J.,
- Chandrasekaran K.,
- Khandheria B.K.