507 



The Various Inclinations of the Electrical Axis of the Human 

 Heart. Part I. — The Normal Heart. 

 By A. D. Waller, M.D., F.R.S. 



(Received March 6— Read May 8, 1913.) 

 (From the Physiological Laboratory of the University of London, South Kensington.) 



CONTENTS. 



Page 



1. Introductory — Weak and Strong Leads 507 



2. Determination of the Electrical Axis 511 



3. Proof of the Formulae, tana = (L-K)/(L + E), tana = 2(E-L)/(R + L) ... 513 



4. Apparatus used 516 



5. Influence of Position and of Eespiration 517 



6. Tone of Heart Muscle 518 



7. Influence of Muscular Exercise 519 



8. Influence of Food 522 



9. Chest Leads 522 



1. Introductory — Weak and Strong Leads. 



The " normal hearts " dealt with in the present communication are those of 

 the regular workers in this laboratory and of ordinary visitors who have 

 wished to see the electrical effects of their own hearts and who have been 

 good enough to allow me to make use of their records ; these have been taken 

 when possible by right and left superior and by right and left lateral leads, 

 so as to afford data for the calculation of the position of the current-axis 

 above and below the heart. No clinical examination of any kind was made 

 in the case of visitors, so that strictly speaking normality of the heart in their 

 case has not been verified. We may, however, assume as probable that the 

 heart of an ordinary active person does not depart widely from the normal. 

 And as a matter of fact the electrocardiograms taken upon such persons are 

 in themselves sufficient evidence of normality to an observer familiar with 

 the signs of abnormality. 



In the entire series of normal persons (amounting to about 200) I have 

 examined during the last three years I have only met with five cases present- 

 ing " abnormal " cardiograms ; of these five, three have volunteered an interest 

 in their own cases that has permitted a careful examination of the heart to be 

 made, in the other two cases no attempt at verification has been made or 

 suggested. 



One of the " normal " cases has proved to be particularly interesting, that 

 namely of Thomas Goswell, my former laboratory man, upon whom I made 

 vol. lxxxvi. — B. 2 p 



