CHAPTER XXII 



Till. PIH SIOLOGY OF THE HEAR*] BE \ I I 



THE ORIGIN AND PROPAGATION OF THE EEAT (Cont'd) — 



FIBRILLATION 



Mode of Propagation in the Auricles 



Prom the mass of evidence we have little doubl that tl 

 originates in the sinoauricular node, and the <i"' 

 as tu lit.w the beal is propagated over the remaindi 

 into tli<- ventricles. Regarding ti Ration 



auricles, two possibilities exist: I it ma) Bpread uniforml) 

 muscular tissu.- of the auricular wall until it reach 

 uiar node, or 2 there may be laid down between th< auricul 



the auriculoventricular node a special strand of highly cond 

 It is no argumenl ngainsl this second possibility thai 

 have been unable by histological methods to differentiate any suel 



ttl! I 



There i^ considerable practical importance attached 

 these questions, particularly with I to t h.- caui 



of cardiac arrhythmia, Buch, for example, as that kno* 

 Tims, it is evident that if the beat is transmitted uniform!) 

 muscular tissue of the auricle, then the whole auricle will bav< 



•.-.1 before the beal 1 ched the auriculoventriculai 



which it is then transmitted t<. tin- ventricles On tl 



■ should travel between th<- two nodes i 

 then the impulse will have arrived at the auriculovei 

 tin- auricle has coi Is a mal I is 



.is to \\ hich of these two > 



vidence Beem rmer 



uniforml) the musculai 



The methods emp d atta< 



the \m th..sr described abo 



the other tin- indin cl In I 

 placed on the aurii 

 auricular node The I \\ 1» i«*li th< 



<-<»ir -h pair u hich is ]»• 



