The effect of pulse pressure upon the coronary blood flow

Gleb Anrep, 1891-1955

Gleb (Vassilievitch von) Anrep was descended from a famous Westphalian family with a proud history of high military distinction which can be traced back to the tenth century. Field Marshal von Anrep was leader of the Livonian Order of Knights who built an outpost of Christianity on the shores of the Baltic. General von Anrep came to St Petersburg at the invitation of Peter the Great and founded the Russian branch of the family in the eighteenth century. Professor Vassili (Basil) von Anrep (1854-1925) was the first member of this family to prefer science to arms. He was born in St Petersburg and studied law in the university there for a year, but he soon tired of academic legal arguments and entered the Medical Academy where he was a brilliant student. He spent two years studying pharmacology in Leipzig, where he described the local anaesthetic action of cocaine and recommended its use in medicine four years before its introduction by Roller. He returned to Russia to be professor of pharmacology, first in Kharkov and then in the Medical Academy in St Petersburg. At the invitation of Prince Oldenburgski he founded the Institute of Experimental Medicine and directed it for several years. At the command of the Emperor he then founded a medical institute for women doctors, which was needed because Moslem women refused to be treated by men. His public duties interfered with his researches and eventually he devoted himself entirely to the reform of education. He held high administrative posts in connexion not only with medicine but also with education in general, and nearly succeeded in introducing compulsory education for all Russians. In the first world war he was at the head of the Russian Red Cross. At the outbreak of the revolution he was thrown into prison, but was released after six months and since the family had come from the Baltic he managed to obtain a Latvian passport. He arrived in London in 1919, stayed with his younger son Gleb for a few years and then left for Paris, where he died in 1925.

Physiological hypotheses--intramyocardial pressure. A new concept, suggestions for measurement

Intramyocardial pressure is supposed to play a major role in systolic coronary flow impediment. Via its assumed relation with radial wall stress it is supposed to be similar to ventricular pressure at the endocardium and decreases linearly to negligible values epicardially. Many attempts to measure intramyocardial pressure have been reported in the literature with rather different results. For instance, with most of the various methods, intramyocardial pressures both higher and lower than left ventricular pressure have been obtained and intramyocardial pressures of more than 125 mm Hg have been found in low-loaded isobaric beats (negligible pressure development in systole). In this "physiological hypotheses paper" I suggest left ventricular pressure and intramyocardial pressure both to result from the varying stiffness of cardiac muscle over the heart cycle. For any intramuscular cavity a time varying pressure-volume (P-V) relation results from the changes in muscle stiffness, the so-called time varying elastance defined as E(t) = P(t)/V(t), and with maximal or systolic elastance called Emax. For a constant contractile state the time varying elastance (E(t)) is suggested to be almost independent of preload and afterload. This concept has been well established for the ventricular cavities, but is here proposed to hold for the interstitial space as well. If a cavity is subject to isovolumic conditions the pressure will be high, but when volume in systole decreases (ventricular ejection or squeezing out of interstitial fluid) pressures will be lower. Thus for constant load on the interstitial cavities, but different loads on the ventricle, left ventricular pressure will vary while intramyocardial pressure remains the same. For low-loaded isobaric beats where left ventricular pressure is minimal intramyocardial pressure will remain the same as during normal ventricular loads and isovolumic beats. Augmented contractility will increase Emax and this will increase left ventricular and intramyocardial pressure only by the same amount if loading conditions of both cavities remain the same. Both ventricular pressure and intramyocardial pressure arise from varying stiffness of cardiac muscle and intramyocardial pressure does not result from left ventricular pressure. A proportionality of left ventricular and intramyocardial pressure is therefore not to be expected. The results on intramyocardial pressure obtained by the different methods used in the literature should be re-interpreted taking this concept into account.

Observations on the Heart-Lung Preparation in the Rat

A technique for producing and studying a heart-lung preparation in the rat is described. The relationship between filling pressure and cardiac output was found to remain constant for 60 to 90 minutes after the start of the extracorporeal circulation. The influence on this relationship of alterations in pulmonary ventilation, arterial pulse pressure, and heart rate has not been found to be critical. The mechanisms underlying deterioration of the preparation have been investigated, but no firm conclusions have been reached. Deterioration was not prevented by the introduction of fresh blood into the circulation. During prolonged experiments, the extracellular-fluid content of the heart was found to increase, the intracellular potassium was unaltered, and the intracellular sodium was reduced. Acute elevation of the sodium concentration in the circulating blood lowered, whereas potassium raised, the cardiac output for a given filling pressure. These opposing actions were found to summate. Slowing of the heart brought about by high concentrations of potassium was antagonized by sodium.

Heart Disease and Filtrable Viruses

A number of filtrable viruses can infect the heart and there produce myocarditis, enadocarditis, and pericarditis. However, this action depends on a coexisting deprivation of oxygen to the heart.

Localizing factors in atherosclerosis

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