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At least 163 records · Page 9Linked to original sources
PubMed1991

[The heart conduction system in corrected transposition of the great vessels].

Authors collected 110 cases of transposition of great arteries between 1972 and 1989. Nine transpositions were corrected and the conduction system was studied on histological serial sections in 6 of them. Two cases of corrected transposition without septal or any other defect were described in detail, one in situs solitus, another in situs inversus. According to the literature, an anterior conduction system often tends to develop in situs solitus, and posterior conduction system in situs inversus. Two presented cases as well as other cases in situs ambiguous quoted in authors' and other papers showed that an arrangement of conduction system in corrected transposition does not depend on general visceral situs but on mutual position of atrial and ventricular septa instead.

Child, Preschool↗
PubMed1979

[Morphology of the principal divisions of heart conducting system of rats].

Light optic and electron microscopic investigation of the sinuauricular node node (spu), atrioventricular node (pzhu) and bundle of His (pzhp) has been carried out in 23 hearts of intact non-inbred male rats. Original techniques of oriented embedding of elements of the conductive system for their electron microscopic identification have been suggested. A morphological classification of specialized cardiac myocytes has been worked out basing on differences in their form and size, number of myofibrils and degree of their regulation. On its base three type of specialized myofibrils have been revealed in the conductive system. Topography of these cells has been described within spu, pzhu and pzhp. The suggested ultrastructural classification of specialized cardiac myocytes is compared with the data obtained for the cardiac conductive system in other types of mammals.

Animals↗
PubMed1978

[Parameters of the bioelectrical activity of the heart conduction system in virtually healthy persons].

Intracardiac conduction was studied on the basis of the conception of the atrial spike potentials. Intracavitary electrograms were recorded from the right atrium, zone of the bundle of His, and the esophagus in 110 persons in 35 of whom no abnormalities were found in the heart and the results of the examination were accepted as control indices. On the grounds of the investigations conducted by them, the authors determined the shape, amplitude, and time of appearance of the spike potentials of the sinus rhythm, atria, and the bundle of His and also the duration of the intervals of intracardiac conduction. Study of the phenomena of bioelectric activization of the atria and the system of the bundle of His in a complex significantly widens the possibilities of selective assessment of disorders of intracardiac conduction at various levels of propagation of the stimulation.

Action Potentials↗
PubMed1977

[Incorporation of 3H-thymidine into the cells of the heart conduction system (sinoatrial and atrioventricular nodes, bundle of His) during cardiogenesis in mice].

The number of DNA synthesizing myocytes in the conductive system, as compared with the working myocardium, was determined by means of light autoradiography. At the same time the number of mitosing cells was counted. The indices of labelled nuclei in the sinoatrial and atrioventricular nodes of the embryos after the single and repeated 3H-thymidine injections were significantly lower than in the working ventricle and atrium. During the postnatal development (3-11 days) only in the sinoatrial node the index of labelled nuclei was significantly lower than in the working ventricle. The proliferative activity in all the myocardium parts fell markedly by the 13th day of development. Following 10 3H-thymidine injections with 12 hrs intervals, the indices of labelled nuclei varied from 0.03 to 0.67% in the working ventricle and atrium and from 0.13 to 1.0% in the conductive system of adult mice. During the embryogenesis the index of labelled nuclei in the sinoatrial node was significantly higher than in the atrioventricular one and during the postnatal development-vice versa.

Animals↗
PubMedDate not supplied

[The effect of calypsol, thiopental sodium and fentanyl on the functional status of the sinoatrial node and the heart conduction system in patients with paroxysmal arrhythmias].

64 patients with paroxysmal arrhythmias caused in 44 cases by collateral atrioventricular pathways have been studied. Endocardial programmed electrical cardiostimulation was applied. It has been established that calypsol at a dose of 2 mg/kg significantly improves the functional state of the sinoatrial node, atrioventricular conduction and conduction in collateral atrioventricular pathways functioning both anterogradely and retrogradely. Fentanyl, already at a dose of 2.5 micrograms/kg inhibits considerably the functional state of the sinoatrial node, without affecting conduction in the normal AV system and in collateral atrioventricular pathways. Thiopental sodium at a dose of 7 mg/kg improves slightly the functional state of the sinoatrial node.

Adolescent↗
PubMed1979

[State of the heart conduction system in the sick sinus syndrome (according to the recording of the bundle of His potentials and the atrial stimulation test)].

It was established that the presence of Samoilov-Wenckebach's periods and prolongation of the H--V interval at low frequency of the imposed rhythm as well as periods of asystolia of more than 1,200 msec are most typical for these patients. An attempt was made to determine the type of cardiac stimulation indicated for such patients from the character of the disorders of rhythm observed in them and the initial frequency of their own cardiac contractions.

Action Potentials↗
PubMedDate not supplied

[The effect of diprivan on the indices of central hemodynamics and the heart conduction system].

Using impedance tetrapolar plethysmography and transesophageal electrical stimulation of the left ventricle, changes in central hemodynamic parameters have been assessed in 46 women during brief (up to 10 min) anesthesias with diprivanum. Bolus injection of diprivanum at a dose of 2.5 mg per 1 kg body weight was used. It has been demonstrated that diprivanum administration decreased BP, which was associated with a drop in total peripheral resistance and stroke volume that led to the absence of compensatory tachycardia to an increase in the cardiac output. The absence of compensatory tachycardia upon diprivanum administration is accounted for by a combined effect of vagotonic diprivanum action and its ability to inhibit moderately the automatic function of the sinoatrial node.

Adult↗
PubMed1978

[Functional morphology of the heart conduction system in acute myocardial infarct].

The results of histochemical, histoenzymological, and fluorescence microscopy studies of the conductive tissue of the heart in acute myocardial infarction in 30 fatal cases are presented. Focal decrease in redox and hydrolytic enzymes, monoaminoxidase, and cholinesterase in elementa of the conduction system as well as changes in the pattern of fluorescence of the specific muscle cells were found. The intensity of metabolic lesions was more pronounced at early stages of myocardial infarction in those cases where the conducting pathways were proximal to the foci of necrosis.

Acid Phosphatase↗
PubMedDate not supplied

[The anti-arrhythmia activity and effect on the heart conduction system of the new anti-arrhythmia preparation bonnecor].

In 10 patients with frequent ventricular extrasystoles there were studied the antiarrhythmic effectiveness and side effects of a new drug bonnecor at a single intravenous administration in doses from 15 to 60 mg (0.17-0.91 mg/kg). It was found that the drug exerted the antiarrhythmic effect at dosages of over 0.4 mg/kg and side effects and toxic effects occurred at dosages of over 0.7 mg/kg. The optimal dose for a single intravenous administration was regarded to be the dose of 0.6 mg/kg. The mechanisms of action of bonnecor were studied during intracardiac electrophysiological investigation. The drug was shown to suppress the conduction of excitation along the atrioventricular node, the His-Purkinje system, the ventricular myocardium and the abnormal pathways of conduction. Thus, bonnecor may be referred to as an agent of class I according to the classification of Vaughan Williams. When administered intravenously (0.6 mg/kg) bonnecor was found to interrupt and prevent the recurrent development of atrioventricular tachycardia and also supraventricular tachycardias at the presence of the abnormal pathways of conduction.

Adolescent↗
PubMedDate not supplied

[Effect of cimetidine on the heart conduction system].

An effect of cimetidine on ECG records has been investigated in a group of 40 patients with gastric or duodenal ulcers and coexisting circulatory disorders. For this purpose ECG has been recorded with Holter's technique (Medilog 2000) together with ECG-recording using high amplifying technique. An intravenous injection of 200 mg of cimetidine produced in some of patients inhibition of the sinus rhythm atrio-ventricular conduction disturbances as well as changes in the end phase of ECG ventricular image. The authors suggest, that intravenous administration of cimetidine to patients with cardiac diseases should be monitored with ECG recording.

Adult↗
PubMed1981

[Characteristics of the operations on the heart conduction system in the pre-excitation syndrome].

Observation of 13 patients with the septal location of additional conducting pathways is given, 2 of them had James' fibres, 1 had a combination of James' and Mahaim bundles, in the remainder the Kent's bundle was in the anterior position. Removal of conduction through Kent's and His' bundles is described in detail. The syndrome of pre-excitation was successfully removed in 10 out of 12 patients, 1 had relapses later and 2 died. A detailed analysis of all 35 operated on patients with the pre-excitation syndrome is given. Good results were obtained in 88.57%.

Adult↗