» 



Electrical Axis of the Human Heart. 53 



into the beginning of expiration, and that the expiratory augmentation goes 

 on into the beginning of inspiration. This lag is probably mechanical, the 

 pneumograph begins to indicate sooner than the heart begins to be raised and 

 lowered. The effects are similar to those seen with the vertical heart, viz., 

 inspiratory diminution, expiratory augmentation. 



• In the right inferior record the respiratory variations of amplitude are 

 regular and relatively large, i.e. in relation to the absolute magnitude of the 

 spike, which in the horizontal heart is small. The range is approximately 

 between 6 mm. in expiration and 9 mm. in inspiration. 



The left inferior record exhibits the negative spike characteristic of the 

 horizontal or soft heart, and with respiration well marked augmentation 

 during expiration and diminution during inspiration. The values as read on 

 this record reach to —13 mm. at the end of expiration and to —6 mm. at the 

 end of inspiration. 



The angles as calculated from these right- and left-hand values are : — 



In expiration — 



i. o 9 + 13 44 ., -, nc0 



tana = 9313 = ~-l = ~ n ' •'• a = 95 • 

 In inspiration — 



tan « = 2 1^ = 0, .-. « = 90°. 



6 + 6 



The values for the right and left superior leads of this subject (of which 

 tracings are not reproduced here) were as follows : — 





Eight superior. 



Left superior. 



tan a. 



a. 





mm. 



mm. 





o 



In expiration 



-5 -0 



7-5 



5-0 



79 



In inspiration 



-2 -5 



10 -o 



1 -67 



59 



Eeviewing the results of this case of horizontal heart as to the general 

 effects of respiration in comparison with the results obtained for the oblique 

 or vertical heart, it appears that these effects with inspiration are as 

 follows : — 





B. O. B. 

 Vertical (and oblique). 



A. D. W. 



Horizontal. 



Transverse Bpike 



Right inferior spike 

 Left „ „ 

 Eight superior „ 

 Left „ „ 



Decrease from 20 "0 to 15 - mm. 



„ 27 -5 „ 24 -0 „ 

 Increase „ 6 - ,, 14 - „ 



„ 5-0 „ 7-5 „ 

 Decrease „ 26-0 ., 18 '0 „ 



Decrease from 15 - to 10 '0 mm. 

 Increase „ 6 '0 „ 9 "0 „ 

 Decrease — 13 - „ — 6*0 „ 

 „ „ - 5-0 „ -2 -5 „ 

 Increase „ 7 '5 „ 10 '5 „ 



