On the Interpretation of Pulse-Tracings

3"28Interpretation of Pulse-tracings ventricular irregularity been appreciated apparently by pathologists as yet., for, with the exception of Radasewsky's '~ paper, I have been unable to find any accounts of examination of the auricle in eases of irregular pulse.My attention was drawn to the subjeet by the results of a series of experiments performed some years ago along with Natthews and during the last year I have through the kindness of Dr. Dock and his staff had the opportunity of examining a considerable number of sphygmographie tracings taken in eases of irregularity of the pulse.I propose in the following pages to attempt to interpret these clinical observations in tet~ns of our experimental results.The object of our experiments, which were performed on dogs, was to ascertain the effects of a single stimulus applied to. the heart.It is unnecessary to revei"c to.most of our conclusions, which bear rather on physiological than on practical points, and which have been published e.lsewhere.'~Let it suffice to sta.te that the mo,vements of the auriele and ventricle we.re recorded separately by a system of levers, and that in a number o,f instanees a sphygmographic tracing was taken simultaneously from the carotid ai~.ery.When a single electric shock was passed through the ventricle at any time except in the refractory period, it was followed by a premature contraction o~ that chamber (Fig. 1, p. 329).In many instances this contraction expelled sufficient blood to cause an undulation in the sphygmographic tracing, this undulation being" lower than that.caused by a normal pulse and occurring at a shorter interval than usual after the last ordinary elevation.But as s general rule the contraction of the ventricle, (premature contraction) was too feeble to cause a pulsation of the artery.In Fig. 1, a premature systole (c) of the ventricle was induced by an electric shock which reached that, chamber at. a point indicated by the erosslines X in the ventricular tracing.It was succeeded by relaxation, and the ventricle then remained quiescent until it was aroused to activity (d) by an impulse descending from the, auricle.The auricular rhythm was unaffected by the irregularity of the ventfiele.If the course: of each impulse be followed from tlte auricle, to. the ventricle and finally to Ztschr.f. kl.