POLYSPHYGMOGRAMS 



291 



with that part of the ventricular diastole during which the ventricle is 

 filling with blood, the auriculoventricular valves being open and the 

 semilunars closed. 



Abnormal Pulses 



The following is a brief description of the main characters of abnormal 

 pulses : 



The Ventricular Form of Venous Pulse. In this no "a" waves ap- 

 pear in the jugular tracing, but the "v" waves are unduly large and 

 dominate the curve. This type of venous pulse may depend upon any 

 one of the following circumstances: (1) onset of auricular fibrillation, 

 in which condition the pulse is usually, though not always, irregular, 

 (2) great increase in the rate of the heart, and (3) overfilling of the 

 right auricle. 



Delayed Conduction and Heart-block. This causes a change in the 



y^M 



i r 



X \ X \ X X X 



Fig. 99. Delayed conduction time. First stage of heart-block. The A-C intervals measure more 

 than 0.2 second. (From E. P. Carter.) 



time relationship of the "a" and "c" waves in the jugular curve. When 

 the heart-block is of the first degree, the "a-c" interval merely becomes 

 lengthened, but when it is of such degree that the normal impulse some- 

 times fails to be conveyed along the auriculoventricular bundle, isolated 

 "a" waves can be detected. In the higher degrees of heart-block there 

 are regularly recurring "a" waves having no constant time relationship 

 to the "c" waves. For the purpose of exact analysis of the curves in 

 suspected cases of delayed conduction, it is often advantageous to draw 

 vertical lines below the tracing representing the beginning of auricular 

 and ventricular systole. This has been done in the tracing reproduced 

 in Fig. 99. 



The line joining these two verticals indicates the conduction time 

 or "a-c" interval. When it exceeds one-fifth of a second, there is 

 delay in the conduction time. 



