Histology of the moderator band in man and other mammals with special reference to the conduction system

Truex, Raymond C.; Copenhaver, W. M.

doi:10.1002/aja.1000800203

Cited by 73 publications

(23 citation statements)

References 21 publications

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“…Whatever is the size and shape, the moderator band must be regarded as the shortest pathway from interventricular septum to the free wall of left and right ventricle in the ostrich and other animals. The Purkinje fibers are large in size and similar in 6 International Journal of Zoology most cellular characteristics in ostrich and dog [30], but in the ostrich, there is no perinuclear clear area. There is a little glycogen in these cells, but in human and mammals these cells are rich in glycogen [4].…”

Section: Discussionmentioning

confidence: 99%

Distribution and Structure of Purkinje Fibers in the Heart of Ostrich (Struthio camelus) with the Special References on the Ultrastructure

Parto

Tadjalli

Ghazi

et al. 2013

International Journal of Zoology

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Purkinje fibers or Purkinje cardiomyocytes are part of the whole complex of the cardiac conduction system, which is today classified as specific heart muscle tissue responsible for the generation of the heart impulses. From the point of view of their distribution, structure and ultrastructural composition of the cardiac conduction system in the ostrich heart were studied by light and electron microscopy. These cells were distributed in cardiac conducting system including SA node, AV node, His bundle and branches as well as endocardium, pericardium, myocardium around the coronary arteries, moderator bands, white fibrous sheet in right atrium, and left septal attachment of AV valve. The great part of the Purkinje fiber is composed of clear, structure less sarcoplasm, and the myofibrils tend to be confined to a thin ring around the periphery of the cells. They have one or more large nuclei centrally located within the fiber. Ultrastructurally, they are easily distinguished. The main distinction feature is the lack of electron density and having a light appearance, due to the absence of organized myofibrils. P-cells usually have two nuclei with a mass of short, delicate microfilaments scattered randomly in the cytoplasm; they contain short sarcomeres and myofibrillar insertion plaque. They do not have T-tubules.

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Section: Discussionmentioning

confidence: 99%

Distribution and Structure of Purkinje Fibers in the Heart of Ostrich (Struthio camelus) with the Special References on the Ultrastructure

Parto

Tadjalli

Ghazi

et al. 2013

International Journal of Zoology

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“…Myocardial cells are typically 70 /xm long and 15 jttm wide (Truex and Copenhaver, 1947;Laks et al, 1967). The anatomical anisotropy produces an electrical anisotropy (Rush, 1963;Clerc, 1976).…”

Section: Discussionmentioning

confidence: 99%

Effect of tissue anisotropy on extracellular potential fields in canine myocardium in situ.

Roberts¹,

Scher²

1982

Circulation Research

237

159

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SUMMARY. The extracellular epicardial potential fields produced by simple depolarization waves in the in situ canine left ventricular myocardium were analyzed. A mathematical model that included tissue anisotropy was developed to explain the observed fields. Values of intracellular (i), extracellular (o), longitudinal (f), and transverse (t) resistivity which gave the best fit between the model and experimental data were (in ohm-cm, mean ± SD): r,,, = 852 ± 232, r,,, = 1247 ± 210, r,, = 291 ± 38, rii = 1677 ± 331. The potential fields around simple stimulated waves on the epicardium can best be explained if the extracellular wavefront voltage is (mean ± SD) 74 ± 7 mV for a wave propagating parallel to the local muscle fibers, and 43 ± 6 mV for a wave propagating perpendicular to these fibers. We conclude that the anisotropy of the electrical conductivity of cardiac muscle has important effects on the propagation of waves of depolarization and on the potential fields produced by depolarization in the intact heart. (Circ Res 50: 342-351, 1982)

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“…Previously, it was shown that at pacing of the middle part of the LV epicardium [21] and RV pacing [16,[22][23][24] the systolic pressure and dP/dt max are reduced, as compared to supraventricular rhythm. Nevertheless, one of the groups has shown better isovolumic indices at LV apex pacing5 and pacing of the middle ventral part of LV [21], as compared to LV base pacing.…”

Section: Discussionmentioning

confidence: 99%

The effect of repolarization duration on the indices of the pump function of the heart ventricles in animals with different types of activation of the myocardium under ectopic excitation of ventricles

Kibler¹,

Nyzhny²,

Shmakov³

2018

Russ Open Med J

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Background -The aim of the work was to study the influence of myocardial repolarization on the indices of the pump function in animals with different types of the myocardial activation (dog, amphibians) under ectopic excitation of the ventricles. Material and Methods -Intraventricular blood pressure in animals was measured using a hemodynamic Prucka MacLab 2000 system under basal and apical locations of the stimulating electrode on the ventricles of the heart. The activation-recovery intervals (ARIs) were determined from unipolar myocardial electrograms recorded in the intramural layers of apical and basal parts of the ventricles in dog (n=16) and amphibians (toads Bufo bufo, n=11; frogs Rana temporaria, n=23). Data are presented as median with lower and upper quartiles.Results -The pacing of the left ventricle apical area in dogs with more prolonged ARIs, as compared with the base, does not change the isovolumic indices of the left ventricle pump function. However, ARIs were longer at the ventricular base -248 (206, 260) ms for dog's right ventricle and 742 (680, 929) ms for froggy ventricle, as compared with the apex in the canine right ventricle -238 (219, 249) ms, and the ventricle in the amphibians -692 (637, 860) ms. Therefore, pacing of the right ventricle in the apical area in dog and ventricular apex in amphibians leads to a significant decrease of their pump function. Conclusion -In the animals with successive (amphibians) and flash-successive (dog) types of activation of the myocardium, parameters of the pump function of ventricles were better at pacing of the area with the longest repolarization at the baseline and worse at pacing of the shortest repolarization area.Keywords: pump function, contractility, pressure, repolarization, activation, activation-recovery intervals, ventricle, pacing, dog, amphibians.Cite as Kibler NA, Nyzhny VP, Shmakov DN. The effect of repolarization duration on the indices of the pump function of the heart ventricles in animals with different types of activation of the myocardium under ectopic excitation of ventricles.

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Histology of the moderator band in man and other mammals with special reference to the conduction system

Cited by 73 publications

References 21 publications

Distribution and Structure of Purkinje Fibers in the Heart of Ostrich (Struthio camelus) with the Special References on the Ultrastructure

Distribution and Structure of Purkinje Fibers in the Heart of Ostrich (Struthio camelus) with the Special References on the Ultrastructure

Effect of tissue anisotropy on extracellular potential fields in canine myocardium in situ.

The effect of repolarization duration on the indices of the pump function of the heart ventricles in animals with different types of activation of the myocardium under ectopic excitation of ventricles

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