[Measurement of the specific electrical resistance of the blood (rho) and its determination mathematically in dogs].

The role of specific electric resistance of blood (rho) in determining systolic cardiac volume by impedance plethysmography is discussed. It is pointed out that the known five mathematical equations for rho estimation by the hematocrit (Hct) and the temperature (T0) differ from one another and are moreover good for humans, but not for experimental animals. A suitable equipment and technique for direct (in vitro) measurement of rho is suggested.

[Normal hemostatic indices in experimental animals].

On the basis of the studies conducted by the authors on 19 nonbred dogs and 25 rabbits of the strain Cincilla and Belgium giant the normal values of the basis indices of hemostasis were determined: thromboelastography (r+k and ma), amount of fibrinogen, number of thrombocytes, thromoboplastic time, time of recalcification. The obtained data are shown on a table. The obtained data could serve as orienting data in examining hemostasis in dogs and rabbits under various experimental conditions and models for investigating various human pathology.

[Model of formation of chronic volume loading in the right heart].

The authors describe an experimental model for examining the changes occuring in the haemodynamics of the small circuit as a result of created artificial defect of the interatrial septum. An original operative technique is used, by which the complete clamping of the right lung artery and vera is avoided and lung complications are prevented. The performed control haemodynamic studies up to one vear after the operation support the efficiency of the proposed model.

[Experimental control of the dye dilution method of measuring telediastolic ventricular volume by the steps in the curve of indicator "washing"].

After a brief discussion on the basis of the dilution method for determination of telediastolic volume (TDV) of the ventricles, the authors described the results from their own experimental studies on 8 nonbred dogs, on whom 186 curves of indicator "washing" (of the dye "Cardiogreen" were recorded, presented on 2 tables. The results showed that the measurements should be made by means of the later steps of the curves. TDV and accordingly the relative stroke volume of both ventricles differed slightly.

[Systolic and diastolic load of right heart and right bundle block].

Analysing the Ecg and VCG of 818 subjects, healthy or with different congenital and acquired cardiopaties, the frequency of right bundle branch block (RBBB) is established to decrease with the increase in age of children, and is observed to be 8.9% in healthy adults. The right bundle block is observed in 82.

On the classification of ballistocardiograms.

An improvement of Brown's classification is described...

[Terminal bundle-branch block (TBB) in acute and chronic overloading of the right heart].

The authors performed a model loading of the right heart ventricle in 40 dogs in 17 dogs--acute tension loading by creating a partial ligature (banding) of the pulmonary artery; the dogs were examined in respect to the changes hemodynamics and ECG for a period of three hours. In the second group of 10 dogs a chronic tension loading of the right heart was created by a partial ligation of the pulmonary artery (banding); the dogs were followed--up in respect to hemodynamic and vectocardiographic changes for a period of one year. In the other group of 10 dogs a chronic loading of the right heart: was formed by operative route and interatrial defect was obtained; the dogs were followed-up in respect to hemodynamics and vectrocardiographic changes for a period of one year.

An improved classification of ballistocardiographic changes.

On the basis of a critical analysis of the most frequently used classifications of ballistocardiographic changes, an improved classification is proposed, which simultaneously respects the degree of pathological changes appraised according to Brown; the configurations and amplitudes of waves and segments, as well as their dependences on time. The proposed classification essentially accepts the symbols used in the classifications used up to the present, thus obviating errors and mistakes which the new classification might involve. The improved classification facilitates a better differentiation of first-degree pathological changes into those caused by disturbances of cardiovascular dynamics and those due to extracardial factors.