90 PULSE RECORDS IN THEIR RELATION TO 



time relations in conditions where there is engorgement of the 

 right side of the heart. Secondly, different writers refer it to 

 different standard events, which constitutes a wide source of 

 error, and but rarely indicate the evidence from which the stan- 

 dards are derived. Thirdly, it is frequently impossible to be certain 

 whether writers are referring to the actual time relations of the 

 events, or whether a phase of the " v " wave is attributed to a 

 particular ventricular movement. It so happens that a definite 

 statement of the relationship of the " v " wave to a standard 

 movement is not of common occurrence. The collected evidence 

 as to the time relations in the normal subject is so involved that 

 it is impossible to consider it in detail. It is held by the majority 

 that the wave commences during the systolic plateau. Qerhardt ( 16 ) 

 and Wenchebach consider that it is a purely diastolic event. 

 Gerhardt times its occurrence with the commencement of the 

 dicrotic wave ; and Wenchebach finds it synchronous with a 

 notch on the downstroke of the cardiogram. The evidence of the 

 tracings of individual writers is nevertheless in favour of the 

 view that the point of commencement is subject to variation, and 

 that it may commence during the plateau or near its termination. 

 Its termination in the " y " depression is universally stated to be 

 synchronous with the opening of the auriculo- ventricular valves. 

 The evidence for this last relationship does not appear to be so 

 conclusive as one might expect from the statements made on the 

 subject. Thus in Mackenzie's tracings the point as a rule corre- 

 sponds to the bottom of the cardiographic downstroke, 1 while in 

 certain of those of Wenchebach (as in Figs. 6 and 7 of his paper), 

 it starts at a point distinctly later. A critical examination of 

 the subject reveals many sources of fallacy, and the majority of 

 tracings are taken on comparatively slow-moving surfaces, so that 

 the error in marking the points is large. Later when cesophageal 

 tracings are discussed it will be seen that the fixation of the " y " 

 depression at the A.O. line involves an obvious discrepancy. 



Other waves have been described on the venous tracing ; a 

 positive wave preceding the " a " wave (Gibson and Ritchie's 

 sinous wave 18 ) ; a positive wave between " a " and " c " (Bard's 

 accident inter-systolique lb ) ; a fourth positive wave following " v " 

 (Morrow's second outflow wave 36b ). There is no unanimity of 

 opinion on the subject, and these waves cannot be regarded as 



1 Or to the bottom of the dicrotic notch. Potain and Gottwalt agree. 



