共查询到20条相似文献,搜索用时 46 毫秒
1.
M. A. Vaikshnoraite A. S. Belogolova V. A. Vityazev Ya. E. Azarov D. N. Shmakov 《Journal of Evolutionary Biochemistry and Physiology》2008,44(2):204-211
Multichannel mapping of electrical field on heart ventricle epicardium and the body surface in frogs Rana esculenta and Rana temporaria was performed at periods of the ventricular myocardium depolarization and repolarization. The zone of the epicardium early depolarization is located on epicardium of the ventricle base posterior wall, while the late depolarization zone—on its apex and on the base anterior wall. The total vector of sequence of the ventricle epicardium depolarization is directed from the base to the apex. The zone of the early repolarization is located in the apical area, while that of the late one—in the area of the base. On the frog body surface the cardioelectric field with the cranial zone of negative and the caudal zone of positive potentials is formed before the appearance of the QRS complex on ECG. At the period of the heart ventricle repolarization the zone of the cardioelectric field negative potentials is located in the cranial, while that of the positive ones—in the body surface caudal parts. The cardioelectric field on the frog body surface at the periods of depolarization and repolarization of the ventricle myocardium reflects adequately the projection of sequence of involvement with excitation and of distribution of potentials on epicardium. 相似文献
2.
V. A. Vityazev D. N. Shmakov N. A. Antonova N. V. Arteeva Ya. E. Azarov S. N. Kharin V. P. Nuzhnyi 《Journal of Evolutionary Biochemistry and Physiology》2007,43(4):433-437
Based on a multichannel synchronous mapping of heart electric potentials, the sequence in time of the ventricle myocardium depolarization was compared with dynamics of distribution of cardioelectric potentials on the dog body surface. The cardioelectric field on the dog body surface at the period of the initial ventricular activity has been shown to be characterized by the presence of two inversions of the mutual disposition of areas of positive and negative potentials. Contribution to formation of distribution of the cardioelectric potentials on the body surface at each moment of the period of initial ventricular activity was made by all myocardial layers involved in excitation. 相似文献
3.
Vitiazev VA Shmakov DN Antonova NA Arteeva NV Azarov IaE Kharin SN Nuzhyĭ VP 《Zhurnal evoliutsionno? biokhimii i fiziologii》2007,43(4):362-365
Based on a multichannel synchronous mapping of heart electric potentials, the sequence in time of the ventricle myocardium depolarization was compared with dynamics of distribution of cardioelectric potentials on the body surface in a dog. The cardioelectric field on the dog body surface at the period of the initial ventricular activity has been shown to be characterized by the presence of two inversions of the mutual disposition of areas of positive and negative potentials. Contribution to formation of distribution of the cardioelectric potentials on the body surface at each moment of the period of initial ventricular activity was made by all myocardial layers involved by excitation. 相似文献
4.
Cardioelectric field (CEF) on the body surface of birds (hen and pigeon) at the period of atrial excitation was studied by the method of the 64-channel synchronous electrocardiotopography. At the period of the atrial depolarization in the birds the zone of CEF negative potentials on the body surface is located cranially with respect to the zone of positive potentials. At the initial moments of P wave the minimum is located in the cranial (hen) or middle (pigeon) third of the dorsal body surface, while the maximum—in the area of the heart projection onto the ventral (hen) or left-lateral (pigeon) body surface. The maximum and minimum of the potential reach the greatest value at the period of the middle part of the P wave (near the peak), their amplitude being higher in pigeons. The distribution dynamics of the CEF potentials on the body surface is similar in different bird species and is characterized by stability in mutual disposition of positive and negative zones. The interspecies and intraspecies CEF variability on the body surface at the period of the atrial activation seems to be due to differences in the heart disposition in the chest. At the period of the atrial myocardium activation, CEF on the bird body surface reflects adequately projection of the potential distribution on epicardium and the sequence of spreading of excitation in the atrial myocardium, including that in the presence of several fronts of depolarization waves. 相似文献
5.
S. N. Kharin D. N. Shmakov N. A. Antonova M. P. Roshchevskii 《Journal of Evolutionary Biochemistry and Physiology》2001,37(2):161-169
Spatial and temporal non-uniform and polyfocal depolarization of the subendocardial, intramural, and subepicardial layers of the ventricle myocardium in the chicken have been established experimentally. Different depth and time of formation of activation centers in the ventricular myocardium provide the appearance of groups of multiple depolarization foci on the epicardial surface of the ventricles. During the initial ventricular activity the cardioelectric field (CEF) on the chicken body surface is characterized by three periods of the dynamics of distribution of potentials: (1) the period of their gradual changes reflecting the electrical activity of excitation foci in the subendocardial, intramural, and subepicardial ventricular layers of myocardium on CEF; (2) the period of inversion consisting of an alteration of the mutual arrangement of the positive and negative CEF areas, this alteration corresponding in time to polyfocal depolarization of the epicardial surface of the ventricles; (3) the period of stability, during which the arrangement of the positive and negative CEF regions does not change, which is due to depolarization of multiple myocardium zones at the final phase of the heart ventricle activation. 相似文献
6.
Vaĭkshnoratĭe MA Belogolova AS Vitiazev VA Azarov AE Shmakov DN 《Rossi?skii fiziologicheski? zhurnal imeni I.M. Sechenova / Rossi?skaia akademiia nauk》2007,93(10):1123-1131
Lowering the temperature is known to prolong the repolarization of cardiomyocytes. However, whether the prolongation of action potentials is uniform throughout the myocardium, and whether this prolongation is obvious in ECG, remains unclear. Ventricular repolarization sequences and body surface potential distributions were studied in 20 frogs Rana temporaria using epicardial and body surface potential mapping. An apex-to-base ventricular repolarization sequence corresponded to the distribution of local repolarization durations was demonstrated at the temperature of 18 degrees C. The body surface potential distribution during the ST-T complex was characterized by the cranial negative and caudal positive potential areas. Under the body cooling to 10 degrees C, repolarization prolonged to a greater extent at the apex that resulted in the base-to-apex repolarization sequence, which, in turn, caused an inversion in the body surface potential distribution with cranial portion of the body being positive and caudal portion being negative. 相似文献
7.
Vaykshnorayte MA Azarov JE Tsvetkova AS Vityazev VA Ovechkin AO Shmakov DN 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2011,159(1):39-45
The study aimed at the simultaneous determination of the transmural and apicobasal differences in the repolarization timing and the comparison of the contributions of these two repolarization gradients to the development of the body surface T wave potentials in animals with the single heart ventricle (fishes and amphibians). Unipolar potentials were measured on the body surface, epicardium and in the intramural (subepicardial, Epi; midmyocardial; and subendocardial, Endo) ventricular layers of 9 pike and 8 frogs. Activation times, repolarization times and activation-recovery intervals were determined. A transmural gradient in repolarization durations in frogs (Endo>Epi, P<0.024) corresponds to the gradient in repolarization times. No significant transmural difference in repolarization duration is observed in pike that produces a repolarization sequence from Endo to Epi (Endo相似文献
8.
Shmakov DN Mostivenko KK Roshchevskaia IM 《Rossi?skii fiziologicheski? zhurnal imeni I.M. Sechenova / Rossi?skaia akademiia nauk》2000,86(6):681-687
The depth of the myocardial wall ectopic focus was found to affect spatial and temporal characteristics of the depolarization process in the heart ventricular surface. Duration of the ventricular epicardial depolarization under the ectopic foci located in subendocardial and intramural layers of the myocardium was shorter than in epicardial stimulation of the ventricles. A dependence of the ectopic excitation duration on the pacing site localization in the epicardium, was revealed. The shortest duration of the depolarization occurred under electrical stimulation of the apex and ventral part of the interventricular septum, whereas the longer one--under pacing the left ventricular base. 相似文献
9.
Vaĭkshnoraĭte MA Belogolova AS Vitiazev VA Azarov IaE Shmakov DN 《Rossi?skii fiziologicheski? zhurnal imeni I.M. Sechenova / Rossi?skaia akademiia nauk》2007,93(8):870-877
Body surface and ventricular epicardial potential distributions during the electrocardiographic QRST interval were studied in pikes with the aid of potential mapping. The earliest epicardial activation was observed at the posterior base near the atrioventricular orifice. The areas of the earliest repolarization were found at the apex and the posterior base, whereas the area of the latest repolarization was detected at the anterior base. In the initial period of the QRS, the minimum was developed in the middle third of the right lateral body surface, and the maximum in the middle third of the ventral body surface. The body surface potential distribution during the ST-Twas characterized by the clear-cut negative potential zone in the cranial ventral area with the rest of the body surface having positive potentials, a pattern being largely unchanged throughout the period of the T-wave. The ventricular epicardial repolarization sequence differed from the activation sequence. The ventricular epicardial depolarization and repolarization sequences as well as epicardial potential distributions are expressed in the cardiac electric field on the body surface during the QRS and ST-T complexes. 相似文献
10.
abramochkin DV Rozenshtraukh LV 《Rossi?skii fiziologicheski? zhurnal imeni I.M. Sechenova / Rossi?skaia akademiia nauk》2008,94(4):414-420
Two points of early activation were shown on the surface of the frog Rana temporaria ventricle using optical mapping technique. These points are located on the left and right ventricular surface at equal distance from apex and base of the ventricle. The excitation approaches to epicardial ventricular surface at these points, and then it spreads all over the surface. Such pattern of epicardial activation is also shown in mammals where it is related to conduction system functioning. Thus, the precursor of conduction system seems to exist in the frog ventricle, too. 相似文献
11.
Tsvetkova AS Kibler NA Azarov IaE Nuzhnyĭ VP Shmakov DN 《Rossi?skii fiziologicheski? zhurnal imeni I.M. Sechenova / Rossi?skaia akademiia nauk》2008,94(5):523-531
The ventricular myocardium is characterized by heterogeneity of activation-recovery interval durations. The transmural ARI gradients are present in the right ventricular apex (ARIs monotonically decreased as one moved from the endocardium to the epicardium), and in the left ventricular base (repolarization in the subepicardial layers was significantly shorter than that in the midmyo cardial layers whereas subendocardial ARIs did not differ from the others). The repolarization pattern of these myocardial regions is governed by the distribution of ARIs. In the apical left ventricular and basal right ventricular areas, no significant transmural differences in the repolarization durations were found. The repolarization pattern of these myocardial regions is governed by the activation sequence. In the right ventricle, ARIs were significantly longer at the base and shorter at the apex. In contrast, in the left ventricle, the apical ARIs were prolonged whereas the basal ARIs were abbreviated. The apex-to-base sequence of myocardial repolarization seems to depend on apex-to-base gradient of activation-recovery intervals durations. 相似文献
12.
Azarov JE Shmakov DN Vityazev VA Roshchevskaya IM Roshchevsky MP 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2007,146(3):310-316
Our study compared the contributions of activation sequence and local repolarization durations distribution in the organization of epicardial repolarization in animals with fast (rabbit) and slow (frog) myocardial activation under sinus rhythm. Activation times, repolarization times and activation-recovery intervals (ARI) were obtained from ventricular epicardial unipolar electrograms recorded in 13 Chinchilla rabbits (Oryctolagus cuniculus) and 10 frogs (Rana temporaria). In frogs, depolarization travels from the atrioventricular ring radially. ARIs increased progressively from the apex to the middle portion and finally to the base (502+/-75, 557+/-73, 606+/-79 ms, respectively; P<0.01). In rabbits, depolarization spread from two epicardial breakthroughs with the duration of epicardial activation being lower than that in frogs (17+/-3 vs. 44+/-18 ms; P<0.001). ARI durations were 120+/-37, 143+/-45, and 163+/-40 ms in the left ventricular apex, left, and right ventricular bases, respectively (P<0.05). In both species, repolarization sequence was directed from apex to base according to the ARI distribution with dispersion of repolarization being higher than that of activation (P<0.001). Thus, excitation spread sequence and velocity per se do not play a crucial role in the formation of ventricular epicardial repolarization pattern, but the chief factor governing repolarization sequences is the distribution of local repolarization durations. 相似文献
13.
Chudorodova SL Roshchevskiĭ MP Roshchevskaia IM 《Rossi?skii fiziologicheski? zhurnal imeni I.M. Sechenova / Rossi?skaia akademiia nauk》2006,92(12):1436-1443
The form and distribution of extracellular cardioelectric potentials and the sequence of the excitation wave propagation on epicardium of the pig atria were studied by the method of multichannel synchronous cardioelectrotopography. The studies have shown that in pig the excitation wave breaks on epicardium of the right atrium at the base of the upper vena cava. Negative initial atrial complexes are registered in this area. Two fronts of excitation wave spread from the zone of initial epicardial activation: one--to upper segments of dorsal and ventral sides of the right atrium, the second--to inter-atrial septum. The excitation wave comes to the left atrium with a delay relative to the beginning of depolarization of the right atrium. On account of the successive movement of the front of the excitation wave from pacemaker the two-phase potentials are formed on greater part of the epicardium of the pig atria. The lower part of the auricle of the left atrium is depolarized in atrial epicardium in the last turn. The sequence of excitation wave propagation in atrial epicardium close to ravenous (dog) and ungulate (sheep) animals and man is typical for the pig, but herewith the differences in time of covering the atria with excitation do exist. 相似文献
14.
J. E. Azarov N. A. Kibler M. A. Vaykshnorayte A. S. Tsvetkova S. N. Kharin V. A. Vityazev D. N. Shmakov 《Journal of Evolutionary Biochemistry and Physiology》2013,49(2):165-174
The distributions of repolarization durations and end of repolarization time were studied on the ventricular epicardium in pikes (Esox lucius) and frogs (Rana esculenta) and in the ventricular intramural layers in toads (Bufo bufo) at the ectopic heart excitation by using method of the synchronous multielectrode cartography (24 unipolar leads). The time of arrival of the excitation wave and the end of repolarization in each lead were determined from the minimum of time derivative of potential at the period of QRS complex and by minimum of T wave, respectively. It has been established that at the ventricle electrostimulation, alongside with deceleration and a change of sequence of myocardium activation, the redistribution occurs of the local durations of repolarization, being longer than in zones of early activation (p < 0.05). At stimulation, the apicobasal gradient of repolarization is predominantly changed due to electrophysiological processes in the apical areas. In all the studied species, at the ectopic excitation of the heart the sequence of its repolarization repeats the depolarization sequence due to a delay of activation (in fish) and redistribution of repolarization durations (in amphibians). 相似文献
15.
Ia E Azarov M P Roshchevski? D N Shmakov V A Vitiazev I M Roshchevskaia N V Arteeva 《Rossi?skii fiziologicheski? zhurnal imeni I.M. Sechenova / Rossi?skaia akademiia nauk》2001,87(10):1309-1317
In anaesthetised rabbits at normal body temperature, the earliest ventricles' epicardial recovery occurs at the heart apex and adjacent left ventricle's surface whereas the latest one occurs at the epicardium of the right ventricle's base. A decrease in the mediastinum temperature to 32 degrees C reversed the recovery sequence. Following the cooling of the heart, the longest prolongation of the activation-recovery interval occurred at the heart apex area and the lowest one--at the right ventricle base. 相似文献
16.
Kharin S Antonova N Shmakov D 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2006,145(4):540-545
The aim of the study was to advance our knowledge regarding the activation process of the ventricular myocardium in birds in which Purkinje fibres penetrate into the ventricular wall to reach the epicardium. A depolarization pattern of the left ventricular free wall was studied in chickens (Gallus gallus) during ventricular paced beats. Duration of the activation process of the left ventricular free wall is significantly increased during ventricular ectopic excitation as compared with sinus rhythm. Its lowest increase occurs during subendocardial pacing of the middle part of the left ventricle, but its greatest increase is observed during subepicardial pacing of the left ventricular base. Multifocality and mosaicity of depolarization of the left ventricular free wall myocardium in chicken are expressed in a considerably less degree during ventricular paced beats in comparison with sinus rhythm. During ventricular paced beats, excitation of the left ventricular free wall is mostly due to the successive spreading of the depolarization wave from pacing sites. 相似文献
17.
Considered are the principles of realization of biophysical models of heart ventricle electrical activity in the form of a double electric layer on the surface of the electrically active myocardium (epicardium and endocardium) and the boundary surfaces dividing the model compartments with different electrophysiological characteristics. The model parameters are the electrophysiological and anatomical characteristics of the heart such as the geometry of the ventricles and the specialized His-Purkinje conduction system, the velocity of depolarization spread over myocardium, the ratio of the velocities of excitation transmission through the Myocardium / His / Purkinje elements of the model, the shape of transmembrane action potentials on the boundary surfaces, the orientation of the intrinsic anatomical axes of the heart relative to the initial set of coordinates, and some other biophysical characteristics of the myocardium. This model is the main unit of a computer simulation system, which includes databases of real and simulated electrocardiosignals. 相似文献
18.
In order to identify the intracellular transmitter involved in the taste transduction process, cyclic nucleotides were iontophoretically injected into the frog taste cells while membrane potentials were recorded intracellularly. Injection of either cyclic GMP or cyclic AMP induced a depolarization response of about 5 mV in the taste cells, but injection of Cl- had no effect. The rate of a repolarization after the depolarization elicited by cyclic GMP was larger than that after cyclic AMP. The possible role of cyclic nucleotide in the taste transduction was discussed. 相似文献
19.
Kharin SN 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2004,137(1):237-244
Activation and recovery sequences were mapped by means of 64-channel synchronous recording of extracellular potentials on ventricular epicardium in chickens. Ventricular epicardium was depolarized due to multiple breakthroughs. The recovery of ventricular epicardium occurs from the apex to the base of heart and does not repeat the activation sequence. Gradients of repolarisation exist over the ventricular epicardium in birds. Repolarisation pattern of ventricular epicardium depends primarily on intrinsic spatial heterogeneities of ARIs over epicardium. 相似文献
20.
J C Brandys W C Randall J A Armour 《Canadian journal of physiology and pharmacology》1986,64(2):152-162
The major canine cardiopulmonary nerves which arise from the middle cervical and stellate ganglia and the vagi course toward the heart in the dorsal mediastinum where they form, at the base of the heart dorsal to the pulmonary artery and aorta, the dorsal mediastinal cardiac nerves. In addition, the left caudal pole and interganglionic nerves project onto the left lateral side of the heart as the left lateral cardiac nerve. These nerves contain afferent and (or) efferent axons which, upon stimulation, modify specific cardiac regions and (or) systemic pressure. In addition, with the exception of the left lateral cardiac nerve, stimulation of each of these nerves produces compound action potentials in the cranial ends of the majority of the major cardiopulmonary nerves demonstrating that axons in each dorsal mediastinal cardiac nerve interconnect with axons in the majority of the cardiopulmonary nerves. Axons in the left lateral cardiac nerve connect primarily with axons in the left caudal pole and left interganglionic nerves. The dorsal mediastinal nerves project distally onto the heart as coronary nerves accompanying the right or left coronary arteries. These innervated the ventricular myocardium which is supplied by their respective vessels. The left lateral cardiac nerve projects directly onto the lateral epicardium of the left ventricle. The dorsal mediastinal and left lateral cardiac nerves are the major sympathetic cardiac nerves. Thus, the cardiac nerves located in the mediastinum at the base of the heart are not simple extensions of cardiopulmonary nerves, but rather have a unique anatomy and function of their own. 相似文献