94 PULSE RECORDS IN THEIR RELATION TO 



the opening of the auriculo-ventricular valves. 1 In these par- 

 ticulars as to the positive wave the curves of Rautenberg agree 

 in that the third negative wave starts at the end of the plateau. 

 According to Young and Hewlett the wave occurs - 1 sec. earlier 

 than the " v " wave in the neck, and they attribute much of the 

 confusion which has arisen in its interpretation to a neglected 

 consideration of this delay. Rautenberg finds a delay both in 

 man and animals ; the average of observations on six human 

 subjects gives the figure at '081 sec. 



If the diagram (Fig. 1) is again referred to, the discrepancy 

 mentioned at the end of the last section will be understood. The 

 majority of the intra-auricular pressure diagrams show the third 

 negative wave as commencing at the A.O. line. If the " y " 

 depression is fixed at the same point, no delay is allowed for. For 

 this reason a curve more nearly corresponding to those given by 

 Porter of intra-auricular pressure is also introduced. If the 

 third negative wave is regarded as terminating on the A.O. line, 

 it becomes necessary to move the " y " depression to a position 

 indicated in the figure by the broken line, marked iff . 



In connection with the delays, it is important to note that 

 transmission of pressure waves in the venous channels is slower 

 than in the arterial, for the tension is less in them, and the waves 

 travel -against and not with the stream. Young and Hewlett 

 estimated the rate of transmission in a case of tricuspid failure 

 at 1*2 m. per sec. Rautenberg's figures indicate a transmission 

 velocity of 1'5 m. per sec. Morrow found in animals a variation 

 in velocity from 1 to 3 m. per sec. 2 



The main conclusions to be drawn from cesophageal curves 

 are, first, the similarity of intra-auricular curves in man and 

 animals ; and secondly, the fact that the separate waves of the 

 jugular pulse show an appreciable delay in transmission from 

 auricle to neck. 3 They are also of importance in providing a 



1 A point estimated apparently as half way down the dowustroke of the cardio- 

 gram. It frequently happens, as in this instance, that the evidence upon which 

 this standard instant is timed is not fully stated. 



2 The rate of transmission of the several waves is not of necessity the same. As 

 will subsequently be seen, it is improbable that they are all of the same nature. 



3 Of further conclusions which have been drawn, there is one which deserves 

 notice. Joachim and Rautenberg have shown in certain cases of heart block that 

 right and left auricles beat in unison. The statement is only approximately true 

 and applies to clinical work. Some recent observations may be quoted in this 

 connection. Stassen (") finds that the right auricle in dogs contracts '02 sec. 



