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The influence of changes in the hydrogen-ion concentration upon the refractory period of the perfused mammalian heart
REVIEWS
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ABSTRACTS
95
ary artery ; (b) occlusion of right branch of pulmonary artery. (4) Ventilation being constant (a) partial to complete occlusion of pulmonary veins. There is no evidence that either increasing CO, or decreasing CO, causes more than an insignificant enlargement of the pulmonary blood volume. When oxygen lack is carried to an extreme degree, blood does slowly accnmulate in the lungs. Under these conditions the left ventricle fails to meet this load before the right is seriously embarrassed. Blood may back up in the lungs to a very fair atiount before pulmonary-arterial pressure is measurably increased. This fact expresses the extreme ela,sticity of pulmonary circulation and accounts for the accumulation of blood in the lungs when aortic discharge is reduced in the early stages of left ventricular failure. The experiments reported constitute a further explanation of the passive position taken by the pulmonary circulation in the general phenomena of the vascular system. Increase in inflow into the right ventricle is the only means fallin g within ordinary experiences which results in increase of pulmonary blood volumes. When the left branch of the pulmonary artery is occluded the right lung gives free passage to the pulmonary blood even when cardiac inflow is greatly increased. Occlusion of the right branch of the pulmonary artery indicates that the left lung is less in vascular size since diminution in aortic output appears at once. On clamping the pulmonary veins the complete occlusion without colistriction of right ventricular flow the lungs can be made to contain slightly more than double the original volume.
Ca?Ar, Edward P., and Diezaaide, Francis R.: The Influence of Changes in the Hydrogen-Ion Concentration upon the Refmctory Period of the Perfused Mammadiaa Heamrt. Bull. Johns Hopkins Hospital,
1.926, xxxix,
99.
The observations detailed in this study were carried out with the purpose of determining whether or not under given constant conditions of cardiac rate with a variation only in the hydrogen-ion concentration of the perfusion fluid any definite relationship could be shown to exist between the refractory period in perfused mammalian heart and the P, of the perfusion fluid. The dog’s heart was isolated, perfused and removed from the thorax by a method previously described by the authors. It was possible to exclude entirely the influence of extrinsic cardiac nerves. It is apparent from the experiments that with a change only in the hydrogen-ion concentration of the perfusion fluid throughout so narrow a. range as P,“7.0 to P, 7.8 there was an abrupt and significazlt altera.. tion in the refractory period of both auricu1a.r and ventricular muscle
of the dog’s heart, the refractory period being lengthened with the aci.d and shortened with the alkaline perfusatc. The importance of this alteration in the duration of the refractory period in relation to re-entrant waves, circus movements and changes in the transmission interval in cardiac muscle suggests itself and is to be emphasized. It is conceivable that in the myocardium, the seat of local disease processes in man, such marginal changes in the hydrogen-ion concentration may occur as to modify the refractory period of the tissues involved leading to disturbances in the normal sequence of events as suggested above.
Taussig, Helen B. : The Anatomy of the Hearts in Two Cases of Situs Traasversus. Bull. Johns Hopkins Hospital, 1926, xxxix, 199. This report is concerned with the anatomy of the heart in two cases of situs transversus, one in an infant and the other in an adult. In the case of the infant it was possible to make a careful dissection of the finer anatomical relations of the heart and blood vessels. In both casesit was possible to study the anatomy of the ventricles. The main gross anatomical structures and the deep muscle bundles of the ventricles presented the mirror image of the normal, while the direction of the superficial muscle bundles remained unchanged. The explanation of this peculiar anatomical relationship of the muscular layers of the ventricles is not known.
Redfield, Alfred D., aad Medearis, Donald N.: The Content of Lactic Acid and the Development of Tension in Cardia,c Muscle. Amer. Jour. Physiol., 1926, lxxvii,
662.
The present paper is an attempt to discover what relationship may exist between the ability of the cardiac muscle to develop tension and its content of lactic acid. For this purpose the measurement of the tension developing in the ‘ ‘ isometric ’ ’ response of a. strip of cardiac muscle has proved suitable. A description of the measurement of tension in muscle strips from the ventricles of snapping turtles is given. The estimation of lactic acid is described in detail. The ability of the ventricular muscle of the turtle to develop tension is closely correlated with its content of lactic acid.
Moore, John Walker, Hamilton, Iodide Method for Determining Assn., 1926, lxxxvii,
W. F., wd Kinsman, J. M.: Ethyl the Circulation. Jour. Amer. Med.
817.
Using the method of Henderson and Haggard for determining the blood flow and blood volume of the human circulation the authors found that the circulation iii normal resting individuals determined by this method was much higher than that determined in the same individuals
AND
ABSTRACTS
95
ary artery ; (b) occlusion of right branch of pulmonary artery. (4) Ventilation being constant (a) partial to complete occlusion of pulmonary veins. There is no evidence that either increasing CO, or decreasing CO, causes more than an insignificant enlargement of the pulmonary blood volume. When oxygen lack is carried to an extreme degree, blood does slowly accnmulate in the lungs. Under these conditions the left ventricle fails to meet this load before the right is seriously embarrassed. Blood may back up in the lungs to a very fair atiount before pulmonary-arterial pressure is measurably increased. This fact expresses the extreme ela,sticity of pulmonary circulation and accounts for the accumulation of blood in the lungs when aortic discharge is reduced in the early stages of left ventricular failure. The experiments reported constitute a further explanation of the passive position taken by the pulmonary circulation in the general phenomena of the vascular system. Increase in inflow into the right ventricle is the only means fallin g within ordinary experiences which results in increase of pulmonary blood volumes. When the left branch of the pulmonary artery is occluded the right lung gives free passage to the pulmonary blood even when cardiac inflow is greatly increased. Occlusion of the right branch of the pulmonary artery indicates that the left lung is less in vascular size since diminution in aortic output appears at once. On clamping the pulmonary veins the complete occlusion without colistriction of right ventricular flow the lungs can be made to contain slightly more than double the original volume.
Ca?Ar, Edward P., and Diezaaide, Francis R.: The Influence of Changes in the Hydrogen-Ion Concentration upon the Refmctory Period of the Perfused Mammadiaa Heamrt. Bull. Johns Hopkins Hospital,
1.926, xxxix,
99.
The observations detailed in this study were carried out with the purpose of determining whether or not under given constant conditions of cardiac rate with a variation only in the hydrogen-ion concentration of the perfusion fluid any definite relationship could be shown to exist between the refractory period in perfused mammalian heart and the P, of the perfusion fluid. The dog’s heart was isolated, perfused and removed from the thorax by a method previously described by the authors. It was possible to exclude entirely the influence of extrinsic cardiac nerves. It is apparent from the experiments that with a change only in the hydrogen-ion concentration of the perfusion fluid throughout so narrow a. range as P,“7.0 to P, 7.8 there was an abrupt and significazlt altera.. tion in the refractory period of both auricu1a.r and ventricular muscle
of the dog’s heart, the refractory period being lengthened with the aci.d and shortened with the alkaline perfusatc. The importance of this alteration in the duration of the refractory period in relation to re-entrant waves, circus movements and changes in the transmission interval in cardiac muscle suggests itself and is to be emphasized. It is conceivable that in the myocardium, the seat of local disease processes in man, such marginal changes in the hydrogen-ion concentration may occur as to modify the refractory period of the tissues involved leading to disturbances in the normal sequence of events as suggested above.
Taussig, Helen B. : The Anatomy of the Hearts in Two Cases of Situs Traasversus. Bull. Johns Hopkins Hospital, 1926, xxxix, 199. This report is concerned with the anatomy of the heart in two cases of situs transversus, one in an infant and the other in an adult. In the case of the infant it was possible to make a careful dissection of the finer anatomical relations of the heart and blood vessels. In both casesit was possible to study the anatomy of the ventricles. The main gross anatomical structures and the deep muscle bundles of the ventricles presented the mirror image of the normal, while the direction of the superficial muscle bundles remained unchanged. The explanation of this peculiar anatomical relationship of the muscular layers of the ventricles is not known.
Redfield, Alfred D., aad Medearis, Donald N.: The Content of Lactic Acid and the Development of Tension in Cardia,c Muscle. Amer. Jour. Physiol., 1926, lxxvii,
662.
The present paper is an attempt to discover what relationship may exist between the ability of the cardiac muscle to develop tension and its content of lactic acid. For this purpose the measurement of the tension developing in the ‘ ‘ isometric ’ ’ response of a. strip of cardiac muscle has proved suitable. A description of the measurement of tension in muscle strips from the ventricles of snapping turtles is given. The estimation of lactic acid is described in detail. The ability of the ventricular muscle of the turtle to develop tension is closely correlated with its content of lactic acid.
Moore, John Walker, Hamilton, Iodide Method for Determining Assn., 1926, lxxxvii,
W. F., wd Kinsman, J. M.: Ethyl the Circulation. Jour. Amer. Med.
817.
Using the method of Henderson and Haggard for determining the blood flow and blood volume of the human circulation the authors found that the circulation iii normal resting individuals determined by this method was much higher than that determined in the same individuals