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Biomedical subjects

A S Dumchius

Publications and source records attributed to A S Dumchius.

17 recordsLinked to original sources
PubMed1991

[The morphofunctional transformation of skeletal muscle as a consequence of electroneurostimulation training].

By means of histological and histochemical methods slices of biopsies of the canine musculus latissimus dorsi have been investigated after electroneurostimulation for three months through the thoracodorsal nerve in situ and after cutting its initial part. Frequency of contractions increases gradually from 30 up to 80 per 1 min every 2 weeks. The preparations are stained with hematoxylin--eosin. Histochemical reactions for adenosinetriphosphatase (ATPase) (incubational medium pH 4.3 and 10.3) and for acetylcholinesterase (AChE) are performed. The muscle, stimulated in situ, preserves its normal structure. Transformation of muscle contractions from fast to slow, as well as increasing AChE activity in myoneural synapses are revealed. The muscle, stimulated after its cutting at its beginning, is subjected to adipose dystrophy. Activity of ATPase and AChE do not differ from that in the control.

Acetylcholinesterase↗
PubMed1985

[Elaboration of criteria for selection of patients with chronic ischemic heart disease for direct myocardial revascularization surgery].

Indications for direct myocardial revascularization were specified on the basis of a new parameter: the disrupted myocardial blood supply zone (DBSZ). Absolute indications for the procedure included: a more than 50% narrowing in the diameter of the main trunk of the left coronary artery; two or 3 vessels affected with the DBSZ accounting for at least 75% of the left-ventricular and interventricular-septum weight. Relative indications included: two or three affected vessels with the DBSZ covering between 50 and 75% of the left-ventricular and interventricular-septum weight; and a more than 50% isolated proximal narrowing of the diameter of the anterior interventricular branch with any type of coronary blood supply, of the right coronary artery, with types 10:10 and 11:9, and of the circumflex branch, with types 5:15 and 6:14.

Coronary Artery Bypass↗
PubMed1983

[Justification of the indications for radio-frequency electrostimulation of the atria and the results of its use in paroxysmal supraventricular tachycardias].

Re-entry tachycardia was found in 182 patients of a total of 275 subjected to electrophysiological investigation of heart function; in 26 of those, a radio-frequency atrial electrostimulation system was implanted. Early postoperative complications were noted in 3 patients: subcutaneous hematoma in 2, and skin decubitus in 1. Long-term follow-up (as long as 7 years) confirmed the efficiency of atrial radio-frequency pacing.

Cardiac Pacing, Artificial↗
PubMed1983

[Methodological problems of quantitative and combined evaluation of the asynergy and volume of the left heart ventricle by contrast ventriculography in patients with ischemic heart disease].

Regional analysis was performed in 24 patients with various forms of left ventricular (LV) asynergy. Three quantitative methods of regional analysis with different types of superposition (SP) of end-phasic contours (EPC) were compared: the radial method, taking into account the dislocation of basal structures, was more sensitive (p less than 0.02) in detecting apical asynergy, as compared to the chordal method, or the radial procedure using a different type of SP. The authors used the radial method of regional analysis for estimating LV volumes in 53 patients. The data obtained with this method were in good correlation with those of the conventional "area-length" technique. It is concluded that the radial method taking into account the dislocation of basal structures is useful in complex and quantitative analysis of regional as well as systemic parameters of LV function.

Cardiac Output↗
PubMed1975

[Constant endocardiac stimulation of the heart ventricles controlled by atrial biopotential].

The technique procedures and the first clinical experience of the atrial biopotential controlled endocardiac electric stimulation of the ventricles applied to 14 patients 17 to 72 years old with complete or intermittent atrio-ventricular block and attacks of Morgagni-Adams-Stocks disease are described. An endocardial detector electrode designed by German scientists was used to take biopotentials of the atrium. The stimulation proved successful in all the patients who were kept under observations for a period from 1 to 30 months. Advantages of the method under review are set forth.

Action Potentials↗
PubMedDate not supplied

[Development of a technic and methodology of myoventriculoplasty using programmable cardio-synchronized electro-neurostimulation].

The present work provides the basis for the technique of myoventriculoplastics, first applied in this country, with the use of programmable cardiosynchronized electroneuropacing. The characteristics of a first Soviet implantable electroneuropacemaker, and original electrodes for electrostimulation of the neuromuscular tissue is presented and the surgical technique suggested. Data of 25 experiments on 8 dogs are included. The maximal follow-up period was 7.5 months.

Animals↗
PubMedDate not supplied

[Electrodes for epicardial electrical mapping].

Medical-technical characteristics of electrodes for epicardial mapping are examined. Most electrodes are bipolar. The differences between them lies either in the contact configuration or in the fixation mode. The dependence of biosignal amplitude and shape on the contact orientation with respect to the direction of excitation spread is described. Free from this dependence are electrodes with a central point contact and a ring contact through the periphery Clinging and screw-in electrodes are useful for long-term monitoring while stick and suction electrodes are recommended for short-term recording from multiple sites. Ring electrodes put on a finger are advantageous in hardly accessible zones.

Electrocardiography↗
PubMedDate not supplied

[Optimization of the geometric shape and contact surface area of endocardial electrodes].

Endocardial electrodes of original construction are described: with polyhedral head, with split contact head and crescent-shaped one. These electrodes proved to be more efficient than that with spherical or cylindrical contact head with equal contact area. The crescent-shaped electrode underwent clinical trial on 63 patients. During 2 years after implantation no dislocation of these electrodes were noted.

Electrodes, Implanted↗