Estudio experimental de la llamada fase de relajación isovolumétrica del ventrículo izquierdo

Aguilar, Juan A. Cosín; Martínez, Amparo Hernándiz; Segarra, M. Teresa Tuzón; Ramón-Llin, Jaime Agüero; Torrent-Guasp, Francisco

doi:10.1016/s0300-8932(09)70896-6

Cited by 17 publications

(16 citation statements)

References 23 publications

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“…This difference in directions in the septum can capture opposite shortenings in the longitudinal strain. This activation and deformation of the sequential fiber also coincides with the findings of experimental studies by sonomicrometry reported by various authors 19,20,27 (Figure 3) where it is evident how there is a shortening of the subendocardium (DS) moments before the ejection phase with a maximum shortening before the traditional isovolumetric relaxation phase, the maximum shortening of the subepicardial AS is recorded once the rapid filling has begun, demonstrating that there is a sequential mechanical activity which follows the segments of the helical pattern (Figure 3: 1-2) , itself the apical short-axis strain velocity vectors demonstrate a radial inward direction of the cavity throughout the endocardium formed by the DS (Figure 2: 1A-B) , in an apical window the strain velocity vectors show an inward motion of the LV cavity of right, left, and apex during early ejection, as ejection period temporally progresses downward motion persists (displacement of base toward apex) during late ejection and now shows leftward directional shift in basal portion of the septum by rotation clockwise by the start of shortening of the AS that will give way to the first diastolic phase (Figure 4: 1A, B, C).…”

Section: Ejection Phasesupporting

confidence: 91%

“…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 .…”

Section: Myocardial Dissection and Percentage Segmental Contribution ...mentioning

confidence: 98%

“…It has been documented that during this phase there is a mechanical shortening of the transverse fibers belonging to the free wall of the RV in continuity with the LS, conditioning the narrowing of the cavity. This forms an "external armor" keeping the base of the ventricles fixed, and compressing the AL (the crosssectional diameters of both ventricles decrease) causing a brief temporary longitudinal lengthening of the LV apex during the pre-ejection interval (increase in the longitudinal diameter of the LV) 19,20,23 . The global translation of these movements of BL is the counterclockwise rotation of the entire heart as seen from the apex as reported by MRI studies 23,24 .…”

Section: Isovolumetric Contractionmentioning

confidence: 99%

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

Antùnez-Montes

Olavarría

et al. 2022

Preprint

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Introduction. The concept of ventricular anatomy as a single muscular band was initially described by Francisco Torrent-Guasp in 1972 and since then, there have been multiple novel contributions to the understanding of the morphology and function of the heart. To date, this concept has been supported and denied by multiple groups of professionals reflecting both the enthusiasm and resistance to the new concept of the single muscle band model. Currently, the single muscular band is the model that meets all the requirements to explain the performance of cardiac mechanics, and its distinctive feature to determine the characteristics of the structure.

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Section: Ejection Phasesupporting

confidence: 91%

Section: Myocardial Dissection and Percentage Segmental Contribution ...mentioning

confidence: 98%

Section: Isovolumetric Contractionmentioning

confidence: 99%

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

Antùnez-Montes

Olavarría

et al. 2022

Preprint

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“…This mechanism is explained by the persistence of the ascending segment contraction during the isovolumic diastolic phase. (16)(17)(18)(19)(20)(21)(22) We have found that the endocardium is completely depolarized during the rst part of the QRS. If according to our studies the depolarization of the ascending segment starts 25.8 ms on average after that of the descending segment and its contraction persists for the same period of time, the condition of ventricular contraction will last approximately 400 ms. On the other hand, as ventricular systole lasts about 300 ms, the remaining 100 ms correspond to the diastolic isovolumic phase (erroneously called isovolumic relaxation, because as we see there is ventricular contraction).…”

Section: Resultsmentioning

confidence: 99%

Cardiac Helical Function

Jorge

Lowenstein²,

Beraudo³

et al. 2020

Preprint

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Background. The aim of this study was to investigate: a) the starts and ends of the myocardial band; b) the slippage between the band segments, when performing both torsion and ventricular detorsion, implies that there should be an antifriction mechanism that avoids dissipating the energy; c) the electrical activation of the endocardial and epicardial bands and secondarily understand ventricular twist and the mechanism of active suction during the diastolic isovolumic phase. Methods. They were used: a) Ten young-bovine hearts (800-1000 g) and seven human hearts (one embrión, 4 g; one 10 years, 250 g and five adult, 300 g/average); b) five patients with no structural cardiac abnormalities and normal QRS complexes underwent three-dimensional endoepicardial electroanatomic mapping. Results. We have found in all the bovine and human hearts studied a nucleus (fulcrum) underlying the right trigone, whose osseus, chondroid or tendinous histological structure depends on the specimen analyzed. All the hearts studied presented myocardial attachment to the rigid structure of the fulcrum. Hyaluronic acid was found in the cleavage planes between the myocardial bundles.Endo-epicardial mapping demonstrates an electrical activation sequence in the area of the apex loop in agreement with the synchronic contraction of the descending and ascending band segments, consistent with the mechanism of ventricular twist. The late activation of the ascending band segment is consistent with its persistent contraction during the initial period of the isovolumic diastolic phase (the basis of the suction mechanism). Conclusions. The finding of the fulcrum gives support to the spiral myocardial band being the point of fixation that allows the helicoidal torsion. The hyaluronic acid would act as a lubricant and provide great resistance to mechanical pressures. This study explains the ventricular twist and the active suction mechanism during the isovolumic diastolic and early ventricular filling phases.Trial. This work does not correspond to a trial

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“…Some authors question that these mechanisms were sufficient to explain rapid left ventricular filling [1][2][3]. A mechanism was postulated by which at the onset of diastole (isovolumic diastolic phase) the ventricle aspirates blood actively [2][3][4][5]. The active mechanism has been expl ained by the spatial arrangement of the muscle band [1].…”

Section: Introductionmentioning

confidence: 99%

Ventricular torsion and cardiac suction effect: The electrophysiological analysis of the cardiac band muscle

Jorge¹,

Benjamen²,

López-Cabanillas³

et al. 2017

Interventional-Cardiology

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Ventricular torsion and cardiac suction effect:The electrophysiological analysis of the cardiac band muscle Introduction and objectives: The Torrent Guasp concept postulates that the ventricles are formed by a continuous muscle band that begins at the level of the pulmonary valve and extends to the aortic root, limiting in this way the two ventricular chambers. This specific anatomical arrangement would support the interpretation of two fundamental aspects of left ventricular dynamics: 1) the torsion mechanism and 2) the physiology of rapid diastolic filling by the suction effect. Methods: Five patients with no structural cardiac abnormalities and normal QRS complexes underwent three-dimensional endoepicardial electroanatomic mapping during ablation of lone atrial fibrillation or concealed epicardial accessory pathways. The propagation times of the electrical activation by the muscular band was measured in milliseconds (ms). Results: 1) The apical loop is activated by a simultaneous depolarization of the distal descending and proximal ascending band segments. 2) At the point of crossing of both bands a radial activation spreads from the descending to the ascending band. From this point, begins a simultaneous and opposing activation of the proximal and distal ascending band.3) The activation of the distal ascending band segment is the latest. Conclusions: The novel activation sequence of the Torrent Guasp band found in this study would explain the previous process triggering the ventricular torsion and suction mechanism. Moreover, this work demonstrates that activation of the ascending band segment completes the QRS. This finding explains the persistent contraction of this muscle segment during early diastole, rejecting the traditional concept of passive relaxation.

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Estudio experimental de la llamada fase de relajación isovolumétrica del ventrículo izquierdo

Cited by 17 publications

References 23 publications

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

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

Cardiac Helical Function

Ventricular torsion and cardiac suction effect: The electrophysiological analysis of the cardiac band muscle

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