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Addition of fentanyl (1.84.10(-7) M) to a circulating solution was shown to unchange the baseline functional potentialities of the myocardium. However, at min 60 of the experiments, these hearts were different from the control ones in the values of aortic blood flow, cardiac output and left ventricular dP/dt. Their functional stability was accounted for by the preserved myocardial capacity to relax and hence to heterometrically autoregulate.

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It has been shown that ATP (24.10(-6) M) administered once into the circulating solution improved strength and speed characteristics of aerobically perfused hearts. The increasing demands of the hearts in oxygen and energy substrates were satisfied due to coronary vessels dilatation without harming the energy status of the myocardium. When the functional parameters of the hearts in the test and control groups did not differ, an exogenously administered ATP was included into the energy metabolism and increased considerably ATP and CP tissue levels, the sum of high-energy phosphates and ATP/ADP ratio. Artificial supplementation of tissue energy resources was accompanied by a decrease in energy-dependent end-diastolic pressure and diastolic left ventricular elasticity and by increased extensibility of the heart muscle, which may improve functional parameters.

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Using thermodilution technique, 110 patients have been examined during aortocoronary bypass surgery. Cardiac output, pump coefficient, cardiac index, stroke index, mean and edge pulmonary pressure, and other parameters of peripheral hemodynamics have been determined. At the end of the operation upon heart function recovery the test patients were administered intravenously a 1% ATP solution at a dose of 0.05 and 0.025 mg/kg/min. In control patients inotropic drugs were not used, cardiac function recovered spontaneously. A thorough clinical analysis of central hemodynamic data in the control and test groups has been performed. A number of positive effects of intravenous 1% ATP solution in the postperfusion period have been revealed. The data obtained indicate that myocardium protection during heart arrest is insufficient and an additional administration of substrates that form energy and recover adequate coronary flow and oxygen consumption is necessary upon heart function recovery in all the cases. The first results of intravenous ATP administration make it possible to consider the above technique absolutely safe and especially useful for the improvement fo some central hemodynamic parameters.

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It has been shown that despite heart hypothermia to 12-15 degrees C the functional parameters under study following 60 min ischemia were considerably lower than their preischemic values. Introduction of fentanyl into the circulating solution enhanced noticeably the protective effect of hypothermia. At all the experimental stages the analgesic led to dose-dependent improvement of heart functions. Its action manifested in attenuation of left ventricular wall tension, a decrease in oxygen consumption and preservation of the coronary flow following ischemia, which enabled the hearts to demonstrate higher contractility and performance.

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The effect of ATP (24 x 10(-6) M) on the contractility of the isolated hearts has been studied. It has been shown that ATP infusions improved postischemic hemodynamics. The favourable effect of ATP was based on the retention of diastolic properties and compliance of the left ventricle. The percent of postischemic reduction in the force and rate of contractions was analogous to the results in the control group, but the hearts on ATP performed a greater volume of work and demonstrated higher functional reserve.

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The addition of fentanyl to the perfusate (up to the concentration of 1.84.10(-7) M) did not change the baseline levels of the parameters studied in the isolated hearts. By the end of the experiments stroke volume, heart rate, coronary flow, heart performance, rates of contractions and relaxations in the left ventricle remained at baseline level and were better than in the control group. The authors hold that reduced O2 demands are the reason for the stabilization of the myocardial function observed. The above peculiarities of fentanyl make it a drug of choice in cardiosurgical patients.

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The effect of droperidol (3.3 x 10(-6) M) on the functional capacities of the isolated heart has been studied. The drug inhibited myocardial contractility. The effect manifested directly after the introduction of droperidol into perfusate (prompt phase). Afterwards the progress of the drug inhibitory effect was slow (slow phase). It is assumed that the difficulties in the use of droperidol in the critical cardiosurgical patients are associated with the attenuation in the realization of the regulatory effects of the central nervous system.

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Using a model of the isolated beating rat heart, the authors compared the protective effect of St. Thomas Hospital cardioplegic solution enriched with glucose and mannitol (StTH-M) and Bretschneider solution (HTK-B). Results showed that, during 120-minute global ischaemia in cardioplegia, StTH-M was able to maintain levels of high-energy phosphates comparable with those found in a group of hearts perfused with HTK-B at 20 degrees C only when the temperature had been decreased to 12-15 degrees C. Under these conditions, repair of metabolic and functional parameters during post-ischaemic perfusion was also similar in both groups.

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The effect of ATP on the functional capacities of the isolated heart has been assessed. It has been shown that the drug at a concentration of 24 x 10(-6) M improves myocardial contractility and increases coronary flow volumetric rate. Favourable ATP effects manifested right after its administration into the circulating solution in improvement of all the physiological parameters, but were unstable. Nevertheless, the presence of ATP in the perfusate ensured high functional reserve and guaranteed stability of the isolated heart performance over 60-min observation period. The paper reviews the prospects of exogenous ATP application in cardiosurgical patients and outlines problems of drug administration techniques, as well as possible difficulties of its clinical use.

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Our studies have revealed a prognostically poor course in postinfarction angina pectoris patients on conservative medicamentous treatment. The mortality rate within the first year of this syndrome onset was 19.8 per cent among conservatively treated patients. Surgical management of these patients had a significantly better prognosis. Despite the fact that there was a great difference in survival rates between the studied groups at the hospital stage, the survival rate was significantly higher at subsequent stages in surgical patients compared to that in the conservatively treated group, and correlated with that in a larger population of matched age. In addition, surgical treatment was found to substantially improve the quality of life in patients with postinfarction angina pectoris which implies lowered frequency of attacks, increased exercise tolerance, and improved working capacity.

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Impute photoconductivity of pyridine solutions of chlorophyll a and pheophytin a in the presence of phenylhydrasin was studied, as well as that of tetraphenylporphin, zinc-tetraphenylporphin, mezoporphyrin, zinc-mezoporphyrin, and palladium-mezoporphyrin in the presence of hydrasin hydrate depending on flash intensity and temperature (20--30 degrees C). The lifetimes of anion-radicals and monoprotonated dianions of the studied pigments were estimated, as well as activation energies of some intermediate stages of photoreduction. From the data obtained the ratio between the constant of the death rate of anion-radicals and the total mobility of negative and positive ion-radical was found.

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