66 Dr. A. D. Waller. Various Inclinations of the 



E ni , or, as I express it, a large transverse and a small or reversed left lateral 

 spike. Precisely similar considerations apply to this sign in relation to 

 diagnosis as have been just stated as regards the right side of the heart. 

 I have seen cases that agree with the clinical statement (but others that do 

 not), and I have seen far more numerous cases of normal persons with small 

 transverse and negative left inferior spikes, and have inferred therefrom that 

 the electrical axis of the heart was approximately horizontal. I have met 

 with this sign at all ages and in all conditions of health, and have become 

 accustomed to expect to find it in anoemic young women and in aged persons' 

 of either sex. I associate it in my mind with a soft or flabby heart muscle, 

 but possess no confirmatory post-mortem evidence of that impression. 



The electrical signs that are presented as being significant of interruption 

 of the right (or left) branch of the auriculo-ventricular bundle of Kent and 

 His consist essentially in a reversed and prolonged R in resembling a left 

 ventricular extra-systole, but occurring in sequence to an auricular con- 

 traction. All the cases hitherto reported which have been confirmed by 

 post-mortem examination have been on the right side, and have been charac- 

 terised electrically intra vitam by a negative left lateral deflection, which 

 has been accepted as an indication of ventricular contraction initiated on the 

 left side. I shall not venture to deny the possible accuracy of the chain of 

 argument upon which the diagnosis of the interruption depends, but in 

 estimating probabilities I think it should be clearly realised that a negative 

 left lateral deflection is of frequent normal occurrence. 



In Part I of this paper it has been shown that the inferior angle « varies 

 within a very wide range ( — 10° to +100°) with the shape and position of 

 the heart. A presumably " soft " heart, of which the muscle is deficient in 

 tone, is sessile upon the diaphragm, and its electrical axis is approximately 

 horizontal. With " hard " muscle the heart, even during diastole, is more 

 nearly erect upon the diaphragm, and its axis is more nearly vertical. The 

 axial angle is decreased by inspiration, increased by expiration ; it is 

 decreased by muscular exercise, increased by repletion of the stomach. I 

 think that it is extremely probable that to this series of statements it may be 

 added that, pathologically, the angle is decreased by engorgement of the 

 right side of the heart (as occurs e.g. in mitral disease), so that the 

 electrical axis may be vertical or actually directed to the l'ight, and increased 

 by hypertrophy of the left side especially (as occurs e.r/. in aortic disease), so 

 that the axis may become horizontal. But since both these conditions, 

 i.e. axis to the right and axis horizontal, are compatible with a normal state, 

 I do think that either a remarkably large left lateral spike or a reversed left 



