Electrical Axis of the Human Heart. 



59 



IM 



40 



20 

 100 

 80 

 60 

 40 

 20 



20 



40 





sl48 



U4I- 























U30- 





































II 



II 



2 ) 

 ? ^ 



mi; 













107 

 St 











1 AO 



















36' 





,93 > 



















yi 



16 \ 











.77 









'6/ 

 7 





175 







— 58 



64 



Jp62> 



r or\7 

 \ / 6 ' 



^6 





54 > 



166 



50. 



\ / * 



N 



» 









151 







<40 - 



1*34 



— V 



i4S 







— X— 

 o 



"3 



crc 



\ 







\ 



rt 







< 



\ 



c \ 



V 







/ ^ 



^0 - 



v\ 

 c \ 

 -o \ 















126 







— s 



"c 



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\ 

















^6 























6> 























1 o 





«-l3 







































—3a 





1-32 



















-40 1 





Fig. 6. — Curves givingthe 

 electromotive values of 

 the several heart leads 

 with values of the axial 

 angle a from 0° to 90°. 



The value of, e.g. the 

 transverse lead in- 

 creases with increase of 

 a ; it decreases with 

 inspiratory decrease of 

 a. The value of, e.g. 

 the left inferior lead 

 decreases with increase 

 of a and becomes nega- 

 tive when a is above 

 64°. The negative left 

 inferior spike of a 

 horizontal heart is 

 diminished by a deep 

 inspiration and can 

 sometimes be reversed 

 to positive. The posi- 

 tive left inferior spike 

 of an oblique heart is 

 increased by inspira- 

 tion and can sometimes 

 be reversed to negative 

 by a maximum effort of 

 expiration. See figs. 7 

 and 9. 



20" 40" 60" 



- Inspiration Expiration 



80' 



