ALBION WALTER HEWVLETT, M.D.
(Assistant Professor of AMedicine at thze Cooper Medical College, San Francisco, Cal.)
The normal venous pulse is characterized by the presence of two main waves. The first of these, the a wave, is due to the contractioni of the right auricle, and immediately precedes the carotid pulse. The other, or v wave, appears in the neck in early diastole coincident with the closure of the semilunar valves.' It originates, however, at a somewhat earlier period, for about . I second is lost by this wave in traveling from the heart to the neck.2 It is probably caused by an upward movement of the auriculo-ventricular junction at the end of systole. The v wave is frequently notched and many believe that the portion preceding the notch is a stasis wave caused by the collection of blood in the auricle previous to ventricular diastole.' Some authors,3 indeed, attribute the entire v wave to this origin. This wave is terminated by the opening of the trictuspid valves and the consequent flow of blood from the right auricle into the right ventricle. It will be noted from the above description of the normal venous pulse that there is a negative downward phase extending from the end of auricular systole to nearly the end of ventricular systole. This is frequently somewhat obscured on tracings by an extraneous third wave due to the carotid pulse. Leaving this latter out of account, the negative phase occurring during the first two-thirds of ventricular systole is one of the most characteristic features of the normal venous pulse. This negative phase indicates a relatively rapid emptying of the venous blood into the heart; and Porter 4 has demonstrated experimentally that the venous flow is more rapid during ventricular systole than at any other portion of the cardiac cycle. If one may judge the *Received for publication Aug. 20, I907.
rate of flow in man from the depth of the negative wave, then it is usual in him also for the most rapid venious flow to occur during ventricular systole. This is especially so during rapid heart action when the pause between the end of ventricular systole and the beginning of the next auricular contraction is most shortened. The accelerated flow of blood toward the heart during ventricular systole is due in part to auricular diastole and in part to the downward movement of the auriculo-ventricular septum at this time. The term "positive venous pulse" has been used by some to indicate a regurgitant venous pulsation, due to a stream of blood being forced back into the veins from the heart. It has been contrasted with the venous pulsations caused by an intermittent interruption of the flow toward the heart, the so-called " negative venous pulse." In order to distinguish between these two forms of pulsation it has been recommended that the external jugular vein be compressed at its center. If it still pulsated when all flow from above was shut off, a regurgitant pulse was believed to be present; whereas if the cutting off of the flow from above stopped the pulse we were dealing with a negative pulse. Unfortunately in practice it is by no means easy to satisfy one's self as to the effect of obstructing the vein in its middle, nor are the data thus obtained of much value. The externial jugular vein in normal animals continues to pulsate below a ligature.5 Furthermore, a regurgitant venous pulse does not necessarily indicate tricuspid insufficiency. It may be caused by the powerful contractions of a right auricle, provided the way from the auricle to the veins is not obstructed by competent venous valves nor by the muscular closure of the caval opening into the right auricle. Riegel I in i 88 i clearly pointed out these objections to the current method of examining the venous pulse and showed that the. important difference between the normal venous pulse and that of tricuspid insufficiency...