Exceptional types of slow heart action / by Thomas Lewis.

  • Thomas Lewis
Date:
[1913]
Catalogue details

Licence: Public Domain Mark

Credit: Exceptional types of slow heart action / by Thomas Lewis. Source: Wellcome Collection.

    9/22 page 227
    the heart beats normally, because the old pacemaker is more active and conse- quently dominates the whole heart. Nevertheless, they are ready to appear so soon as the old rhythm is checked. To such a nodal rhythm I apply the adjec- tive homogenetic, and class it under this term both with the old rhythm and with the idio-ventricular rhythm, for they all have the same quality. Homo- genetic impulses, as I term them, are not defined according to site of origin. I use the term to distinguish such impulses from those which have the extra- systolic quality, namely, prematurity or rapidity of production; and these, in contradistinction to homogenetiec, I call heterogenetic. The double classification, including site of formation and quality of impulse, clearly emphasizes the four distinct types of heart-beat. 1. The homogenetic type, arising in the old pacemaker ; of which the normal heart-beats are the sole examples. 2. The homogenetic and ectopic type; of which the idio-ventricular and idio-nodal beats are characteristic examples. 3. The heterogenetic type, arising in the old pacemaker; of which the so-called sinus extra-systole is the sole example. 4. The heterogenetic and ectopic type; into which category all extra- systoles, other than those of sino-auricular origin, and all hitherto described paroxysms of tachycardia fall. Case II. The second series of records which I propose to discuss at the present time were taken from a young man, who was sent to me by Dr. Mac- kenzie for electro-cardiographic examination. He was usually the subject of slow and generally irregular heart action. Through the kindness of Dr. Mac- kenzie I am in possession of the polygraphic curve. It is shown in Fig. 6. An irregular pulse curve is accompanied by a venous pulse tracing of the ventricular form ; each arterial beat is accompanied by candv waves. There is no pre-systolic wave @, though a curious wave (marked ?) occurs from time to time, the meaning of which is not clear; it is related to the preceding and not to the succeeding systole, but does not appear constantly. The electro-cardiograms are seen in Fig. 17. Fig. 17 (J and JZ) shows a regular ventricular beat of constant type and of the supraventricular form. There is no trace of auricular summit in any lead or during any part of diastole, neither are there any of those oscillations. which are now known to characterize auricular fibrillation. So far as I am aware, no current interpretation is sufficient in explanation of these curves. Auricular fibrillation is excluded by the regular ventricular action present in these electro-cardiograms and in the left-hand portion of the polygraphic curve, and by the absence of oscillations ; weakness of the auricular contraction * might explain the absence of a waves but would not explain the absence of P summits. Simultaneous auricular and ventricular contraction is improbable, though perhaps. not definitely excluded, by the type of venous curve, The type of curve (electric. and venous) was unchanged when irregularity occurred (Fig. 17, [/Z). 3 Venous stasis was not present.
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