American journal of physiology . sHght, is trans-mitted through the aortic valves becausethe relatively low pressure at this stage ofthe cardiac cycle insures a correspondingly Figure 3. Preliminary vibra- rc-^r^i ^ 1 tions (Vorschwingungen) low elasticity coerncient of the aortic valves. Thus is explained the fact that this wave is less distinct or disappears entirely when aortic pressure is high. Upon the same theory, the rapid drop (2-3) would signify a movement of the valves into the ventricle, incident to a lower ventricular pressure. that no adequate intraventricular pressure curve at th
American journal of physiology . sHght, is trans-mitted through the aortic valves becausethe relatively low pressure at this stage ofthe cardiac cycle insures a correspondingly Figure 3. Preliminary vibra- rc-^r^i ^ 1 tions (Vorschwingungen) low elasticity coerncient of the aortic valves. Thus is explained the fact that this wave is less distinct or disappears entirely when aortic pressure is high. Upon the same theory, the rapid drop (2-3) would signify a movement of the valves into the ventricle, incident to a lower ventricular pressure. that no adequate intraventricular pressure curve at that time had been recorded, this interpretation was only tentatively adopted by Frank who also recognized the possibihty of an extra-cardiac influence. This negative depression (.005 second to .01 second in duration) was followed by an oscillation (3-5) varying from .0166 to .03 second. This wave Frank explained as follows: The aortic valves are under a tension proportional 1 Frank: Zeitschrift fiir Biologic, 1905, xlvi, p. A, in the aortic systemafter Frank, B and C inthe pulmonary artery en-larged and transcribedfrom waves of Fig. and letters referredto in text. In view of the fact 6 Carl J. Wiggers to the difference between the arterial and ventricular the ventricular pressure rises suddenly during the iso-metric period, Anspannungszeit, the valve tension decreasesbecause the pressure difference on the two sides diminishes andthe valves bulge toward the arterial side. This bulging canoccur only by a movement of the arterial column and as itoccurs very rapidly, we obtain a vibration. According to Frank,this vibration measures the period of rising tension in the ven-tricle previous to the opening of the semilunar valves (Anspan-nungszeit). In the preliminary vibrations of the pulmonary artery similarvariations are discerned (Fig. 2,, B,C). The wave a—h evidentlycorresponds to the auricular contraction. In many cases this isfollowed by an elevati
Size: 1301px × 1921px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookautho, bookcentury1800, bookdecade1890, booksubjectphysiology
