268 



Tilt: CIKCI'I.ATIOX OF T1IK BUH)I> 



with the path which the impulse takes, produces a much greater differ- 

 ence of electric potential than is seen in the normal electrocardiogram. 

 When the impulse arises in the right ventricle near the base, the prin- 



Fig. S9. — Paroxysmal tachycardia. Auricular origin. Note that the P deflection falls back on. T. 



Rate 200 per, minute. 



cipal R deflection is upwards in both leads 1 and 2. Arising near the 

 apex, the principal R deflection is up in lead 1 and down in lead 2. Two 

 extra systoles both arising in the right ventricle are shown in Fig. 87. 



Fig. 90. — Auricular fibrillation. Leads 1, 2, 3. Note the coarse fibrillation waves between the 

 R peaks, and the absence of any B deflections in relation to R. Also the unequal spacing of the R 

 deflections. 



In the case of the left ventricle, a basal impulse gives a downward 

 principal deflection in lead 1 and up in lead 2. When the aberrant fo- 

 cus is located near the apex of the left ventricle, the principal deflee- 



