Laminar structure of the heart: ventricular myocyte arrangement and connective tissue architecture in the dog

1995 ◽  
Vol 269 (2) ◽  
pp. H571-H582 ◽  
Author(s):  
I. J. LeGrice ◽  
B. H. Smaill ◽  
L. Z. Chai ◽  
S. G. Edgar ◽  
J. B. Gavin ◽  
...  
Keyword(s):  
Connective Tissue ◽  
Three Dimensional ◽  
Length Distribution ◽  
Ventricular Myocardium ◽  
Left Ventricular ◽  
Tangential Section ◽  
Connective Tissue Matrix ◽  
The Right ◽  
Tissue Matrix ◽  
Number Of Branches

We have studied the three-dimensional arrangement of ventricular muscle cells and the associated extracellular connective tissue matrix in dog hearts. Four hearts were potassium-arrested, excised, and perfusion-fixed at zero transmural pressure. Full-thickness segments were cut from the right and left ventricular walls at a series of precisely located sites. Morphology was visualized macroscopically and with scanning electron microscopy in 1) transmural planes of section and 2) planes tangential to the epicardial surface. The appearance of all specimens was consistent with an ordered laminar arrangement of myocytes with extensive cleavage planes between muscle layers. These planes ran radially from endocardium toward epicardium in transmural section and coincided with the local muscle fiber orientation in tangential section. Stereological techniques were used to quantify aspects of this organization. There was no consistent variation in the cellular organization of muscle layers (48.4 +/- 20.4 microns thick and 4 +/- 2 myocytes across) transmurally or in different ventricular regions (23 sites in 6 segments), but there was significant transmural variation in the coupling between adjacent layers. The number of branches between layers decreased twofold from subepicardium to midwall, whereas the length distribution of perimysial collagen fibers connecting muscle layers was greatest in the midwall. We conclude that ventricular myocardium is not a uniformly branching continuum but a laminar hierarchy in which it is possible to identify three axes of material symmetry at any point.

Toward a kinetic theory of connective tissue micromechanics

1993 ◽  
Vol 74 (2) ◽  
pp. 665-681 ◽  
Author(s):  
S. M. Mijailovich ◽  
D. Stamenovic ◽  
J. J. Fredberg
Keyword(s):  
Connective Tissue ◽  
Three Dimensional ◽  
Elastic Fibers ◽  
Tissue Elasticity ◽  
Field Equations ◽  
Fiber Network ◽  
Rate Dependent ◽  
Connective Tissue Matrix ◽  
Tissue Matrix ◽  
And Diffusion

The aim of this study is to develop unifying concepts at the microstructural level to account for macroscopic connective tissue dynamics. We establish the hypothesis that rate-dependent and rate-independent dissipative stresses arise in the interaction among fibers in the connective tissue matrix. A quantitative theoretical analysis is specified in terms of geometry and material properties of connective tissue fibers and surrounding constituents. The analysis leads to the notion of slip and diffusion boundary layers, which become unifying concepts in understanding mechanisms that underlie connective tissue elasticity and energy dissipation during various types of loading. The complex three-dimensional fiber network is simplified to the interaction of two ideally elastic fibers that dissipate energy on slipping interface surfaces. The effects of such interactions are assumed to be expressed in the aggregate matrix. Special solutions of the field equations are obtained analytically, whereas the general solution of the model field equations is obtained numerically. The solutions lead to predictions of tissue behavior that are qualitatively, if not quantitatively, consistent with reports of a variety of dynamic moduli, their dependencies on the rate and amplitude of load application, and some features associated with preconditioning.

scholarly journals Quantified growth of the human embryonic heart

Biology Open ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. bio057059 ◽  
Author(s):  
Jaeike W. Faber ◽  
Jaco Hagoort ◽  
Antoon F. M. Moorman ◽  
Vincent M. Christoffels ◽  
Bjarke Jensen
Keyword(s):  
Heart Development ◽  
Three Dimensional ◽  
Ventricular Myocardium ◽  
Left Ventricular ◽  
Embryonic Heart ◽  
Growth Patterns ◽  
Right Atrial ◽  
Left Ventricular Myocardium ◽  
Atrioventricular Canal ◽  
The Right

ABSTRACTThe size and growth patterns of the components of the human embryonic heart have remained largely undefined. To provide these data, three-dimensional heart models were generated from immunohistochemically stained sections of ten human embryonic hearts ranging from Carnegie stage 10 to 23. Fifty-eight key structures were annotated and volumetrically assessed. Sizes of the septal foramina and atrioventricular canal opening were also measured. The heart grows exponentially throughout embryonic development. There was consistently less left than right atrial myocardium, and less right than left ventricular myocardium. We observed a later onset of trabeculation in the left atrium compared to the right. Morphometry showed that the rightward expansion of the atrioventricular canal starts in week 5. The septal foramina are less than 0.1 mm2 and are, therefore, much smaller than postnatal septal defects. This chronological, graphical atlas of the growth patterns of cardiac components in the human embryo provides quantified references for normal heart development. Thereby, this atlas may support early detection of cardiac malformations in the foetus.This article has an associated First Person interview with the first author of the paper.

scholarly journals Quantitative Assessment of Myocardial Ischemia in Multi-Vessel Coronary Artery Disease by Multimodal Stress Echocardiography with Semi-Supine Bicycle Ergometry

2020 ◽  
Vol 15 (6) ◽  
pp. 813-819
Author(s):  
S. N. Koretskiy ◽  
O. M. Drapkina ◽  
F. B. Shukurov ◽  
D. K. Vasiliev
Keyword(s):  
Stress Echocardiography ◽  
Peak Load ◽  
Three Dimensional ◽  
Ventricular Myocardium ◽  
Cardiovascular Complications ◽  
Artery Occlusion ◽  
Left Ventricular ◽  
Myocardial Imaging ◽  
Left Ventricular Myocardium ◽  
Bicycle Ergometry

Stress echocardiography is a modern widely used method of noninvasive diagnosis of coronary heart disease and stratification of the risk of cardiovascular complications. In addition, exercise echocardiography is an important tool to clarify the localization of ischemia and establish a symptomassociated artery for management of patient with known coronary angiography data. This is especially important in multivessel lesions, the presence of an occluded artery or borderline stenosis. Currently, various stress agents are used for stress echocardiography in clinical practice: pharmacological drugs (dobutamine or adenosine), transesophageal or endocardial pacing, treadmill, semi-supine bicycle. To detect signs of ischemia usually used only visual estimation of local contractility in the two-dimensional gray-scale mode. Modern modes of myocardial imaging, such as speckletracking echocardiography or three-dimensional visualization, are practically not used. In the presented clinical case, the possibility of combining standard and modern imaging modes to clarify the localization and quantification of ischemia in multivessel coronary lesions, including chronic artery occlusion, is shown. As a stress agent, a semi-supine bicycle was chosen, the use of which allowed to obtain a qualitative image of the left ventricular myocardium at rest and at peak load, suitable for assessing deformation and threedimensional visualization. Evaluation of left ventricular myocardial deformation by speckle-tracking echocardiography was more accurate than standard diagnosis in detecting signs of ischemia in a patient with multivessel lesions. Three-dimensional imaging was inferior in sensitivity to speckletracking stress echocardiography and, at present, seems to have more research value.

scholarly journals P798 Right atrial phasic function and correlation with right ventricular function in patients with reduced left ventricular ejection fraction and no pulmonary hypertension:insights from 3D echocardiography

2020 ◽  
Vol 21 (Supplement_1) ◽  
Author(s):  
A E Vijiiac ◽  
D Muraru ◽  
F Jarjour ◽  
K Kupczynska ◽  
C Palermo ◽  
...  
Keyword(s):  
Left Ventricular Ejection Fraction ◽  
Ejection Fraction ◽  
Right Ventricular ◽  
Three Dimensional ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Ventricular Ejection Fraction ◽  
Pump Function ◽  
The Right ◽  
Conduit Function

Abstract Background The right atrium (RA) is a highly dynamic chamber with 3 mechanical functions (reservoir, conduit, booster pump) and prognostic implications in heart failure (HF) and pulmonary hypertension (PH). However, RA function and its interplay with the right ventricular (RV) performance in patients (pts) with reduced left ventricular ejection fraction (LVEF) and without PH remain to be clarified. Methods We used three-dimensional echocardiography to study 55 pts (61 ± 14 years, 43 men) with LVEF < 40% no more than mild tricuspid regurgitation (TR), and maximum velocity of the TR jet < 3 m/s. We measured the three-dimensional RA total, passive, active ejection volumes (EV) and the respective emptying fractions (EF). In addition, we compared RV volumes and ejection fraction (RVEF) between patients with normal and abnormal RA function. Results Mean LVEF was 30 ± 7%. Mean echo-derived pulmonary vascular resistance was 1.64 ± 0.54 Wood units. 28 pts (51%) had reduced RA reservoir function (total EF = 34 ± 9%), 34 pts (62%) had reduced RA conduit function (passive EF = 15 ± 4%), and 10 pts (18%) had reduced RA pump function (active EF = 11 ± 3%). Pts with reduced RA reservoir function showed larger RV end-systolic volume (RVESV 124 ± 48ml vs. 90 ± 32ml; p = 0.004) and lower RVEF (38 ± 8% vs. 46 ± 6%; p < 0.001) than pts with normal RA function. Pts with reduced RA conduit function showed smaller RV stroke volume (RVSV 65 ± 19 ml vs. 80 ± 22ml; p = 0.009). Pts with impaired RA pump function showed larger RVESV (142 ± 45ml vs. 99 ± 41ml; p = 0.02) and lower RVEF (36 ± 6% vs. 43 ± 8%; p = 0.006). RVESV was positively correlated with total (r2 = 0.47, p < 0.001), passive (r2 = 0.29, p = 0.03) and active (r2 = 0.39, p = 0.003) RAEV, while it was negatively correlated with total (r2=-0.41, p = 0.002), passive (r2=-0.34, p = 0.01) and active (r2=-0.31, p = 0.02) RAEF. RVSV showed a positive correlation with both total (r2 = 0.4, p = 0.002) and passive (r2 = 0.41, p = 0.002) RAEV. Finally, RVEF was positively correlated with total (r2 = 0.51, p < 0.001), passive (r2 = 0.47, p < 0.001), and active (r2 = 0.36, p = 0.007) RAEF. Conclusions RA dysfunction is not uncommon in pts with reduced LVEF, even in the absence of PH. In these pts, RA function is associated with significant changes in RV function. The RA acts as a dynamic modulator of RV pump function by redistributing RV filling and ejection force among reservoir, conduit and pump functions in the setting of altered hemodynamics. The clinical and prognostic significance of RA function in pts with reduced LVEF warrant further studies.

scholarly journals Aorta–bal kamra tunnel sikeres sebészi kezelése modern noninvazív képalkotó diagnosztika alapján

2015 ◽  
Vol 156 (28) ◽  
pp. 1140-1143
Author(s):  
István Hartyánszky ◽  
Márta Katona ◽  
Krisztina Kádár ◽  
Asztrid Apor ◽  
Sándor Varga ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Postoperative Management ◽  
Left Ventricular ◽  
Aortic Sinus ◽  
First Case ◽  
History Of ◽  
Dimensional Echocardiography ◽  
Aortic Orifice ◽  
Three Dimensional Echocardiography ◽  
The Right

Aortico-left ventricular tunnel is a rare congenital cardiac defect, which bypasses the aortic valve via the paravalvar connection from the aorta to the left ventricle. The authors report the history of a 14-year-old boy with aortico-left ventricular tunnel in whom the aortic orifice arose from the right aortic sinus and was closed by a pericardial patch. The diagnosis was confirmed by combined two-dimensional and real time three-dimensional echocardiogram and magnetic resonance imaging. This is the first case, in which these complex diagnostic imaging methods have been used in the pre- and postoperative management of this defect. Optimally the new transthoratic three-dimensional echocardiography would be needed to define the anatomy and functional consequences of the aortico-left ventricular tunnel and in the postoperative follow-up. Orv. Hetil., 2015, 156(28), 1140–1143.

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