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Biomedical subjects

B Bednarík

Publications and source records attributed to B Bednarík.

At least 19 recordsLinked to original sources

[Effect of celiprolol on isoprenaline-induced myocardial necrosis].

The assessed elevated catecholamine levels in the organism during substantial physical or mental stress lead to changes in the heart rate and to intensification of contractions. The demands of the heart muscle as regards increased oxygen supplies and are not met. This may have serious consequences for the patient. The authors wanted to find out therefore whether the beta-blocker celiprolol will be able to reduce the negative effect of large amounts of catecholamine in the organism and thus play a part in the prevention of myocardial damage. When celiprolol was administered half an hour before isoprenaline, the extent of necrosis caused by catecholamine was reduced. When administered half an hour after isoprenaline administration, the marked protective effect was no longer observed. The necroses in the heart muscle were similar as in animals given catecholamine only.

Animals

The effect of cordarone on isoproterenol-induced damage to the myocardium in rats.

In this experimental work we evaluated the effect of preventively administered Cordarone on the myocardial damage of rats, caused by isoproterenol. Cordarone had prevented the early mortality of rats up to 1 h, however, after the administration of high doses of Cordarone the late mortality of experimental animals was increased. In the group of rats, which were treated by Cordarone there were almost no small necroses of myocardium, which were, however, contrary--very often found in the control animals. We guess that this effect of Cordarone is caused by its influence on the heart rate, which is slowing down, by its antiarrhythmic effect and by its efficiency to improve the perfusion of myocardium by its power to decrease the resistance of coronary vessels.

Amiodarone

[The effect of Neo-Gilurytmal on heart lesions induced with isoprenaline].

Influence of Neo-Gilurytmal was studied upon catecholamine heart lesion in rats of two weight categories: In bigger ones (350-420 g) the lesion was diminished, in smaller animals (200-230 g) any protective influence did not occur. Sensitivity of myocardium to Neo-Gilurytmal is supposed to concur with that to catecholamine effect in rats of increasing weight.

Ajmaline

Mechanical combined heart supporting system for prevention of irreversible ventricular fibrillation after experimental cardiogenic shock.

To determine whether haemodynamic effective support of the failing heart can prevent spontaneous irreversible ventricular fibrillation (IVF) after experimental cardiogenic shock, 63 open chest dogs were assigned randomly into four groups--two control groups (combined heart failure--CHF) and two MCHSS-treated (combined heart failure and non-pulsatile bypass with intraaortic counterpulsation). The CHF was produced by occlusion of the anterior descending coronary artery (group I) or the left circumflex coronary artery (group II) and by an artificial shunt between the pulmonary artery and right atrium. IVF were observed in 10 out of 22 control dogs (group I) and im 17 out of 21 control dogs (group II). In the 20 dogs with the CHF (10 animals in each group) the MCHSS was performed in the course of two hours. During the heart support no IVF were observed in any of the dogs. The difference between the incidence of IVF in the control and treated animals is statistically significant (Chi square = 21.9767 greater than Chi square 0.005).

Animals

Electrolyte changes in myocardial injury.

The shifts in the myocardial electrolyte metabolism during secondary or primary cardiopathies in dogs and rats, respectively, are described. Major attention is paid to the changes of Ca in the myocardial tissue. The increase in the Ca level after ligation of ramus circumflex of the left coronary artery, or after F-COL + Na2HPO4, and vitamin D2 administration, is regarded as a triggering process for more profound successive changes in the metabolism of the myocardial cell, which eventually lead to depletion of the high energy phosphate reserves. In the dogs with experimental coronary occlusion, the normalization of the myocardial ionogram, i.e., the ratio of K, Na, Ca, and Mg, was achieved by means of the mechanical heart assist, using the original design of the blood pump, where bypass and counterpulsation principles work simultaneously. The normalization of the Ca level in this case was achieved on the basis of a marked reduction of the volume work of the left ventricle, which is secured by the bypass component; on the other hand, the counterpulsation component of the combined pump secures the reduction of pressure work placed upon the left ventricle (represented by the decrease fo the end-diastolic pressure) and helps in the opening of the collaterals in the infarcted area during early diastole. Thus, the oxygen supply to the ischemic zone is improved. On the basis of our experiments with the combined blood pump, the failing heart is supported, not only hemodynamically, but also from the metabolic point of view. A similar effect is achieved by the administration of K-Mg-aspartate, and K-L- or K-DL-aspartate in dogs with experimental infarction. In primary electrolyte steroid cardiopathies characterized by necrosis, K-Mg-aspartate or K-aspartate only prevents the Ca increase in the myocardial tissue, whereas Mg-L- or Mg-DL-aspartate remains without andy effect. The necrotic changes observed after vitamin D2 administration are always accompanied by extremely high Ca levels in the myocardium. It shown in our experiments that administration of K-Mg-aspartate or Fe-dextran decreases the Ca level and reduces the necrotic and myolytic changes in the cardiac tissue. The authors recommend as an effective means in the therapy of acute heart failure the combination of mechanical heart support with the causative pharmacological therapy.

Animals