ENDOCARDIAC PRESSURE 



through the jugular vein. When such tubes are introduced and connected 

 with some form of pressure-recording apparatus, accurate tracings of the 

 variations in pressure during the heart-beat are obtained. 



FIG. 159. Simultaneous Registration of Curves of the Left Intraventricular Pressure 

 (lower), the Aortic Pressure (middle), and the Cardiac Impact (upper). Time, o.oi of a 

 second. (Hurthle.) 



Systole, 



Diastole/. 



FIG. 160. Schematic Cardiogram I, and Intraventricular Pressure Curves from the 

 Dog. The ventricular pressure curve of the descending type is represented by the dotted 

 line. Pressure in millimeters of mercury, time in tenths of a second. (Hurthle.) 



Chauveau and Marey have been able to record and measure with much 

 accuracy the variations of the endocardiac pressure and the comparative 

 duration of the contractions of the auricles and ventricles. They placed 



