POLYSPHYGMOGRAMS 



275 



The rise in the curve following depression x is caused by the filling of 

 the auricle with blood. This goes on until v, when the tricuspid valves 

 open, allowing the blood to fall into the ventricle. 



Fig. 97. Reduced tracings from carotid, aorta, ventricle, auricle and jugular, to show the 

 general relationships of the various waves. An electrocardiogram is also shown. Note that the 

 jugular and auricular curves have the same contour, and that the depression (x) in them occurs 

 during systole of the ventricles. (After Lewis.) 



To interpret the cardiogram, receiving tambours are adjusted to the 

 radial and apex beat with both writing styles in the same perpendicular, 

 and the other directions described under "venous pulse" are followed. 

 The following points are ascertained: (See Fig. 98.) 



Fig. 98. Polysphygmograms including jugular, apex and radial tracings. Line 4 on the radial 

 tracing is first of all located. It is then transferred (by measurement from the alignment mark on 

 the right edge of the tracing) to the jugular and 1/10 second subtracted from it, giving line 3. 

 When this is similarly transferred to the apex tracing, it falls somewhere on the upstroke the be- 

 ginning of which is line 2. 



