Evidence that the myocardium is a continuous helical muscle with one insertion

Helical Structure of the Ventricular Myocardium. A Narrative Review of Cardiac Mechanics.

“…As a consequence of the shortening of the DS during ejection, lengthening of the AS occurs, beginning its intervention in this phase with its contraction, it shortening during the criticized phase of isovolumetric relaxation 30 . At this moment the overall result of its shortening causes a clockwise reversal after ejection since it reverses its ejection-conditioned movement which is counterclockwise, (Figure 2: 2A-B) as a result, the LV elongates from the straightening of the AS just when the DS has stopped contracting but maintains rigidity and tension 33 (Figure 4: 2A-C) together with the recently reported osteochondroid tissue, the fulcrum or support point of the myocardium is obtained 17 for the AS straightening, base elevation as it continues to contract unopposed for approximately 90 ms more. The AS according to experimental studies begins to contract approximately 60 ms later than the DS, followed by a time interval of 90 ms that marks the difference between the end of the DS contraction, followed by the shortening of the AS 31,32 .…”

“…Contracting together with a greater radius of curvature. This interaction is responsible for systolic torsion, and recent electrophysiological studies denote a radial transmural activation in the middle third of the interventricular septum, 17 explaining this phenomenon by coactivation of the DS and AS simultaneously (Figure 3) . The AS shortens during cocontraction to compress the cavity, but its effect by raising the base of the ventricles is counteracted by the dominance of the SD contraction, which, as we have seen, already contributes a greater percentage to the ventricular mass 17,29 .…”

“…The sequential and continuous contraction of the different muscle segments and, thanks to the global threedimensional orientation as a non-orientable triple torsion geometric surface, explain the mechanical phenomena that occur during the cardiac cycle, as we will review below. Therefore, the traditional concept of electromechanical apex-base activation 18 contradicts what has been shown by experimental studies 17,19,20 as well as data from echocardiography strain and strain rate quantify an initial movement of the base before shortening ventricular 21,22 MRI analyses also support the evidence of contradirectional base-apex rotations in the different phases of the cardiac cycle 23,24 .…”

“…Antúnez-Montes and Sosa-Olavarría quantified the mass contribution provided by each segment in which the myocardium is divided, according to the single muscle band model (unpublished data), finding that on average the RS contributes 25%, the LS 12%, the DS 37%, and the AS 26%.In this way, the BL contributes approximately 37% and the AL 63% to the ventricular economy. (Table 1) This does not differ from what was recently reported by Trainini, analyzing the contribution of different segments of the helicoidal heart in the free walls of the right and left ventricle and the septum, they have reported histologically a wide area of osteochondroid tissue in a vicinity of the right fibrous trigone which they have decided to call (cardiac fulcrum), something that Torrent-Guasp had attributed to the residual volume of blood calling this fulcrum as (Hemoskeleton), supposed to facilitate the ventricular torsion movements 15,16,17 . The osteochondroid structure had already been identified as similar to "bone tissue" attributing it to the nature of the fibrous trigone by Antunez-Montes in 2014, with comments in a video class found on the virtual platform https://www.youtube.com/watch?v= HZmaPA837Q8&t=727s at 10:22.…”

Anatomy, histology, development and functions of Ossa cordis: A review

“…In human cardiac anatomy, in addition to trigones and atrioventricular rings, the heart has a cardiac fulcrum (Figure 1 ). Works by Trainini and coauthors elucidated the value of this structure in humans and proposed its function and importance once they had observed the attachment of the continuous myocardium to the fulcrum and naming the structure the ‘cardiac fulcrum’ (Trainini et al, 2021 ; Trainini et al, 2022 ). They proposed that the fulcrum, a thickening at the base of the aorta made up of a collagen matrix, is essential for anchoring the myocardial band allowing the band to contract and relax, maintaining efficient cardiovascular blood flow (Trainini et al, 2021 ; Trainini et al, 2022 ).…”