POLYSPHYGMOGRAMS 



295 



by a sudden onset and an intermittent course. In the former condition 

 the paroxysm lasts for a period varying from a few minutes to several 

 days; in auricular nutter the attack, though it may be of brief duration, 

 more frequently lasts for months. 



Auricular Fibrillation. The contractions of the auricle, as already ex- 

 plained, are entirely irregular, and the jugular tracings show an en- 

 waves, the radial tracing being characterized by 





Fig. 105. Auricular fibrillation. Note the absence of all "a" waves from the jugular tracing, the 

 marked irregularity of the radial pulse, and the occurrence of "c" and "v" during the sphygmic 

 period. (From E. P. Carter.) 



the complete absence of a dominant rhythm and by great variation in the 

 length of the individual beats from one cardiac cycle to the next. This 

 irregularity does not repeat itself, and the long pauses are not simple 

 multiples of the shortest pause. Tracings from a case of auricular 

 fibrillation are shown in Fig. 105. 



