- Email: [email protected]
The capillary supply in normal and hypertrophied hearts of rabbits
744
THE
AMERICAN
HEART
JOURNAL
Identical experiments were performed upon five dogs with results similar to those obtained in the cat. In a separate series of cats all the major cardiac veins were ligated to produce venous congestion. Although the heart became markedly congested and its surface “wept” from transudation, the lowering of the pH of the coronary venous blood was so slight as to be questionable, and there was only a small change in the lactic acid content. After twenty or thirty minutes of congestion the heart continued to perform its function in an apparently normal manner. Under the conditions of the experiments the lowering of the pH of the coronary venous blood to 6.6 or below after a few minutes of ischemia indicates a much greater acid change in the cardiac muscle. The significance of this chemical alteration is discussed with reference to the occurrence of pain in isehemic lesions of the heart and of the extremities. In view of the sensitivity of pain endings to acid (Moore, Moore, and Singleton, 1934), it is concluded that in such clinical cases the accumula’tion of acid metabolites in the area devoid of arterial circulation can well be of a magnitude to account for the pain.
AUTHOR. Shipley, R. A., Shipley, Louise J., and Wearn, Joseph T.: The Capillary in Normal and Hypertrophied Hearts of Rabbits. J. Exper. Med.
Supply 65:
29,
1937. During normal growth of the rabbit heart, muscle fibers enlarge, and the capillaries multiply so that a relatively constant capillary supply per unit of tissue is maintained from the time of birth to maturity. In cardiac hypertrophy the muscle fibers enlarge, but the capillaries do not multiply, and, as a result, the capillary supply per unit of tissue is reduced. The decreased concentration of capillaries in the hypertrophied heart would eonstitute an impediment to the adequate exchange of metabolic substances, but the seriousness of the impediment cannot be estimated without further physiological data.
AUTHOR. Marcu, J.: The Genesis of Embryonic Tube Phenomenon. Klin. Wchnschr.
Heart Action
on the Basis of a Hydraulic
15: 600, 1936.
The author noted that, when a continuous stream passes through membrane, it becomes converted into an intermittent stream. beating of the embryonic hear% to a similar phenomenon.
an elastic rubber He attributes the Ii.
Schoedel, W. : Action of Vasodilator Substances on the Work Arch. f. d. ges. Physiol. of Active Skeletal Muscles. Pfliigers The author muscle adenylic
found acid,
that vasodilators, did not improve
like muscle
histamine, contraction.
acetyleholine,
N. E.
and Blood Flow 237:
190,
1936.
adenosine,
and
L. N. E.
Paschkis, K. : Anemia and Anoxemia of the Heart Muscle-An Experimental vestigation of Angina Pectoris. Wien. Arch. f. inn. Med. 28: 447, 1936. In rabbits small doses of adrenalin cause no electrocardiographic same doses cause changes in the T-wave, however, if the animal The adrenalin by increasing 0, metabolism of the heart summates cause anoxemia in the heart muscle.
In-
changes. The is made anemic. with anemia to
L. N. K.
THE
AMERICAN
HEART
JOURNAL
Identical experiments were performed upon five dogs with results similar to those obtained in the cat. In a separate series of cats all the major cardiac veins were ligated to produce venous congestion. Although the heart became markedly congested and its surface “wept” from transudation, the lowering of the pH of the coronary venous blood was so slight as to be questionable, and there was only a small change in the lactic acid content. After twenty or thirty minutes of congestion the heart continued to perform its function in an apparently normal manner. Under the conditions of the experiments the lowering of the pH of the coronary venous blood to 6.6 or below after a few minutes of ischemia indicates a much greater acid change in the cardiac muscle. The significance of this chemical alteration is discussed with reference to the occurrence of pain in isehemic lesions of the heart and of the extremities. In view of the sensitivity of pain endings to acid (Moore, Moore, and Singleton, 1934), it is concluded that in such clinical cases the accumula’tion of acid metabolites in the area devoid of arterial circulation can well be of a magnitude to account for the pain.
AUTHOR. Shipley, R. A., Shipley, Louise J., and Wearn, Joseph T.: The Capillary in Normal and Hypertrophied Hearts of Rabbits. J. Exper. Med.
Supply 65:
29,
1937. During normal growth of the rabbit heart, muscle fibers enlarge, and the capillaries multiply so that a relatively constant capillary supply per unit of tissue is maintained from the time of birth to maturity. In cardiac hypertrophy the muscle fibers enlarge, but the capillaries do not multiply, and, as a result, the capillary supply per unit of tissue is reduced. The decreased concentration of capillaries in the hypertrophied heart would eonstitute an impediment to the adequate exchange of metabolic substances, but the seriousness of the impediment cannot be estimated without further physiological data.
AUTHOR. Marcu, J.: The Genesis of Embryonic Tube Phenomenon. Klin. Wchnschr.
Heart Action
on the Basis of a Hydraulic
15: 600, 1936.
The author noted that, when a continuous stream passes through membrane, it becomes converted into an intermittent stream. beating of the embryonic hear% to a similar phenomenon.
an elastic rubber He attributes the Ii.
Schoedel, W. : Action of Vasodilator Substances on the Work Arch. f. d. ges. Physiol. of Active Skeletal Muscles. Pfliigers The author muscle adenylic
found acid,
that vasodilators, did not improve
like muscle
histamine, contraction.
acetyleholine,
N. E.
and Blood Flow 237:
190,
1936.
adenosine,
and
L. N. E.
Paschkis, K. : Anemia and Anoxemia of the Heart Muscle-An Experimental vestigation of Angina Pectoris. Wien. Arch. f. inn. Med. 28: 447, 1936. In rabbits small doses of adrenalin cause no electrocardiographic same doses cause changes in the T-wave, however, if the animal The adrenalin by increasing 0, metabolism of the heart summates cause anoxemia in the heart muscle.
In-
changes. The is made anemic. with anemia to
L. N. K.