[iitriivcntriciil.'ir and Aortic Pressure Ciirves. 433 



; waves of the ventricular plateau followed by the dicrotic notch, and 

 I occasionally (Fig. 8) the three are very shaiply marked. There is. one 

 I wave distinctly and invariably present immediately following the 

 i dicrotic notch; this is usually followed by another less distinct, and 



sometimes there are one or more small following undulations. A pftint 

 I of interest is the slight depression, seen best in the two first beats of 



Fig. 8, whicli occurs immediately before the sharp upstroke. 



1 Relation ot the Intraventricular to the Aortic Pressure Curves. 



I If we compare the aortic and intraventricular pressuie curves 



j taken immediately following one another, so that the heart was beating 



! at the same rate and under similar conditions as regards arterial 



pressure, as, for instance. Figs. 2 and 8, by superposing them one 



upon the other (as Frédéricq has done ^) we see how close is the 



agreement between the first part of the aortic curve and the upper 



part of the ventricular curve. The figure at the end of this paper 



was obtained in the following way. Images of curves Figs. 2 and 8 



. were projected by means of a lantern on to a piece of paper, at such 



5 a distance from the lantern lens that the magnification was about 



twice the natural size, and their outlines were followed by a pencil. 



In the Figure, the aortic cmwe is at the top and the ventricular one 



it at the bottom; the middle curve was obtained by first tracing a ven- 



I tricular curve like the bottom one, and then projecting on to it an 



* aortic curve, like the top one, taking care of course that the systolic 



upstrokes of the tw^o curves coincided. We see now that the first 



two waves of the ventricular plateau coincide exactly with the first 



I two aortic waves, and that the third corresponds in position, but is 



I rather higher in the aortic curve. The descent of the two cm-ves 



corresponds for a certain distance, i. e., to the point where Hiiithle 



' and Frédéricq place the closure of the aortic valves; from this point 



the ventricular curve continues its descent, while the aortic cmwe is 



raised again by the arrival of the dicrotic w^ave. The point where 



^) Éléments de Physiologie. S^'d- Edit. 1893, and in Centralblatt f. Physiologie. 

 1893, p. 42. 



Internationale Monatsschrift für Anat. u. Fhys. XI. 2b 



