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Results for “HEART CONDUCTION SYSTEM”

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At least 55 records · Page 3Linked to original sources
PubMed2004

The screening for X-linked Emery-Dreifuss muscular dystrophy amongst young patients with idiopathic heart conduction system disease treated by a pacemaker implant.

The X-linked Emery-Dreifuss muscular dystrophy (X-EDMD) is a hereditary muscle disorder associated with cardiac involvement. Sinus node dysfunction and atrioventricular conduction defects, typical of X-EDMD, occur in both males and females and may result in sudden cardiac death unless treated by permanent pacing. The objective of the study was to determine the frequency and relevance of X-EDMD in heart conduction system disease in young individuals treated with a pacemaker implant. The medical history of 3450 paced individuals in the region of South Moravia, Czech republic, was reviewed. Thirty-five patients, 20 males and 15 females, with idiopathic heart conduction disease of onset before age 40 were identified and screened for X-EDMD. Within these 35 individuals, only one male was found to carry a mutation in X-EDMD gene. We conclude that the clinical relevance of X-EDMD in heart conduction system disease is very low. It should, however, be included into the diagnostic work-up of young male individuals with idiopathic cardiac conduction disturbances.

Adolescent↗
PubMed2002

[Changes of the heart conduction system after exposure to fluorouracil].

Using 20 male rats the electron microscopic study of conducting system of the heart was performed to assess the effect of fluorouracil--an antineoplastic drug belonging to antimetabolite group. A daily dose of 15 mg/kg of fluorouracil was injected intraperitoneally for 5 days; three courses of injections with the intervals of three weeks were performed. Toxic effect of fluorouracil is demonstrated after the first course of injections and is revealed as a predominant injury of pacemaker cells in sinoatrial and atrioventricular nodes. Latent pacemaker myocytes and Purkinje fibers undergo "calcium injury" during the second and the third courses of fluorouracil injections. The irreversible damage of contractile and specialized myocytes results in fibrosis which develops predominantly in the areas of atrioventricular bundle and its branches.

Animals↗
PubMed1979

[Methods of investigating the heart conduction system].

A description is presented of improved methods of examining the conductive system of the heart designed for special routine investigations. The methodology comprises: a) injection of coronary arteries with contrast medium and their X-ray visualization, b) special technique of heart postmortem, c) histological investigation with a view to the precise topography of the particular parts of the conductive system including detailed histological processing in series cestions by means of staining methods: haematoxylin-eosin, elastica-van Gieson, P. A. S., and Heidenhain.

Coronary Angiography↗
PubMed1995

Immunoreactive atrial and brain natriuretic peptides are co-localized in Purkinje fibres but not in the innervation of the bovine heart conduction system.

Recently, we observed that atrial natriuretic peptide (ANP) immunoreactivity was present in Purkinje fibres and nerve fibre varicosities in the conduction system of the bovine heart. In order to elucidate further the morphological correlation between natriuretic peptides and the conduction system, the distribution of brain natriuretic peptide (BNP) was examined. The different parts of the conduction system in the bovine heart were dissected out and processed for immunohistochemistry with antisera against BNP and ANP. BNP immunoreactivity was frequently observed in Purkinje fibres of the atrioventricular bundle, whereas only a few Purkinje fibres in the ventricular part of the conduction system showed immunoreaction. BNP immunoreactivity was detected in regions of the Purkinje fibres which also showed ANP immunoreactivity. BNP immunoreactivity was not observed in nerve fibre varicosities. Methodologically, a larger number of small BNP immunofluorescent granular structures was observed by using an elution-restaining technique instead of conventional immunohistochemistry. The present study shows that BNP and ANP immunoreactivities frequently occur in the atrioventricular bundle and that they are co-localized in Purkinje fibres, but not in nerve fibre varicosities, in the conduction system. As previously has been proposed for ANP, the present observations suggest that also BNP may act in an autocrine and/or paracrine way in the conduction cells.

Animals↗
PubMed1992

[Cellular architecture of the sheep myocardium and heart conduction system as revealed with silver-impregnation method].

Morphological studies were carried out to delineate the cellular architecture of the myocardium and heart conduction system in adult sheep using the silver-impregnation method. Reticular fibers were heavily stained in a deep black color, while collagen fibers were less intensely silver-stained in a brownish color. Individual working myocardial cells were ensheathed by thin reticular fibers and showed a polygonal form, and were connected with adjacent cells mainly end-to-end and sometimes side-to-side. Thick collagen septa were distributed between masses of myocardial cells. The nodal cells in both the sinoatrial (SA) node and atrioventricular (AV) node were spindle shaped, smaller in size than myocardial cells, and surrounded by thin reticular fibers. The bundles of SA node cells were linearly oriented, while those of AV node cells formed a reticular pattern. The cells in the His bundle and Purkinje system were oval in shape, larger in size than myocardial cells and formed the strands composed of 4-8 cells. Each stand was surrounded by thick reticular fibers. These cells had both end-to-end and side-to-side contacts. Purkinje cells were followed by transitional cells which were in contact with myocardial cells. On the other hand, the reticular fibers and collagen fibers showed characteristic structures at the different portion of heart. The present study discusses the topographical relationship between cardiac muscle cells containing the conduction system and the connective tissue sheaths surrounding muscle cells.

Animals↗
PubMed1990

[Characteristics of the status of autonomic innervation and of the functioning of the heart conduction system in alcoholism].

As many as 71 men fit for work (aged 32.6 years on the average) suffering from stage II alcoholism were examined with the aid of variation pulsimetry. The findings obtained were compared with the data of electrophysiological exploration of the heart by transesophageal pacing. In the majority of the patients (80.2% of cases), the changes in vegetative homeostasis manifested themselves primarily by activation of the sympathetic nervous system and combined both with a noticeable decrease of sinus node automatism function and an appreciable deterioration of conduction in the sinoatrial zone and atrioventricular junction. In addition, sinus node automatism function and sinoatrial conduction were inhibited to a greater degree in sympatheticotonia whereas deterioration of antegrade impulse conduction in the atrioventricular junction manifested itself mostly in association with predominant vagus influences. It is emphasized that in patients with alcoholism, sympatheticotonia was attended by different impairments of the heart rhythm in half of the cases.

Adolescent↗
PubMed1978

Cytoskeletal filaments of heart conducting system localized by antibody against a 55,000 dalton protein.

Cow heart conducting cells characteristically contain cytoplasmic intermediate-sized filaments. We report here the preparation of a specific antibody to a 55,000 dalton protein of isolated cow Purkinje fibres. Confirmation has been obtained that these filaments consist of the 55,000 dalton protein, using the indirect immunofluorescence technique. Cross-reaction is seen with vascular endothelium and smooth muscle cells of various origin, suggesting close identity of different types of intermediate-sized filaments.

Animals↗
PubMed2006

[Purkynje fibers of the heart conduction system--history and the present time].

It has been 160 years now since Purkynje published the finding of conduction fibers in the heart in Archiv f. Anatomie u. Physiologie and it has been 166 years since his publication in polish version. Already during Purkynje's life, some anatomists had solved the morphology of these fibers but nobody at that time knew of what great physiological and medical importance this discovery would be for medicine. It was seen as late as in the 20th century and in contemporary times. Purkynje's work indicated the cascade of these discoveries, which were leading in the beginning of the previous century to the formulation of the basic scheme of the conduction system. Purkynje fibers or Purkynje cardiomyocytes are part of the whole complex of the cardiac conduction system which today is classified as specific heart muscle tissue, being responsible for the generation of the heart impulses. From the point of view of ultrastructural composition, the cells of different parts of the cardiac conduction system are partly similar. In contrast to the heart contractile cardiomyocytes, the cells of the cardiac conduction system including Purkynje fibers have a small amount of myofibrils,small mitochondrias, light cytoplasm and a higher glycogen content, but no T-tubular system. They can be detected with some morphological methods. Nevertheless the cells of the conduction system are not completely uniform. They differ in size, number of nexuses-gaps and intercalar discs in individual parts of the conduction system. Nevertheless, these specialized cells work as a whole-unit. Nowadays, the morphology research of all the parts of cardiac conduction system, including Purkynje fibers, is focused on ultrastructural, histochemical and genetical problems. The question is, wheather with future gene/cell therapy disturbances of the conduction system such as arrythmias, can be prevented and cured by replacing the electrical pacemakers with biological ones. If Jan Evangelista Purkynje lived today, he would be surprised but surely delighted with the high degree of research concerning his discovery and its clinical application.

Animals↗
PubMed1987

[Evaluation of the heart conduction system in patients with ventricular allorhythmia].

Intracardiac electrophysiologic studies of the sinus node and conductive system of the heart were carried out in 51 patients with ventricular allorhythmias. In half of the cases, ventricular allorhythmias occurred in patients with impaired sinus node operation and abnormal atrioventricular impulse conduction. It is suggested that anti-arrhythmic drugs associated with adverse chrono- and dromotropic effects should be used with caution.

Adult↗