Auricular fibrillation and its relationship to clinical irregularity of the heart / by Thomas Lewis.

  • Thomas Lewis
Date:
[1910?]
Catalogue details

Licence: In copyright

Credit: Auricular fibrillation and its relationship to clinical irregularity of the heart / by Thomas Lewis. Source: Wellcome Collection.

    36/80 page 338
    adjacent peaks R R . The pieces of curve referred to sliovv no resemblance to each other. A similar example but an exi)erimental one is shovn in Fig. 17 (the last half of the curve). The first half of this curve represents the escape following vagal stimulation. The oscillations which are so comj)letely unmasked by the prolongation of diastole escajie attention in the succeeding cycles. In the clinical curves tlie peak R is exaggerated, as compared to the normal. The same remark applies to most experimental curves (the comparison may be made in Figs. 20 and 21 and in Fig. 29). The difference is also present in curves taken direct from the ventricle (Fig. 31 III and IV). Again, there is the fact that in experimental as well as in clinical curves the general character of the ventricular complex is unaltered. In the dog this can be readily demonstrated by leading from any two pointsof the ventricular surface. The same type of curve is yielded whether the auricle is fibrillating or in co-ordinate contraction. Fig. 31 III and IV may be compared. The former, taken while the auricle is fibrillating, shows a faster heart beat to the right and the last phases of the shorter cycles are curtailed. To the left of the same figure, the full complex is shown while the heart is escaping from the inhibitory slowing. The ventricular complexes are of the same form as those exhibited while the seciuence is normal, and the heart regular (Fig. 31 IV). The same fact may be shown when the oscillations lack prominence. Leads from the upper and lower part of the chest of the same animal gave similar and normal ventricular curves with one or other mechanism present (Fig. 31 V and VI). The two illustrative curves show the same events, the passage from fibrillation to normal ser[uence,but in VI the galvanometer was arranged to give an excursion approximately three times as great as in V. The electrocardiographic curves, experimental and clinical, are alike in every other respect. The irregular distribution of the ventricular peaks R, the direction of these peaks (direction of base negativity) and the submerged variation T, are features lield in common. There is a further characteristic, which deserves more atRntion. It is common to both clinical and experi- mental curves. There is no fixed relationship between the heights of the peaks R, and eitlier tlie jiauses M hicii ])recede tliem or the height of corres- ponding carotid beats. The absence of botli relationshii.s is shown in Figs 15 and 1/ I he same disproportions are seen in the condition known as heart alternation*, and it is not improi.able tliat a common factor aids in its geneiation under tlie two sets of eircunistances. Rut though 1 believe a ,>henonienon of this sort plays some part, yet in certain of the records it is obviously a minor factor. It will be clear that when the oscillations are nean'l'^u'dsr’’ r ^ relative positions of e e.arde .17 1 imlividual oscillation mav be Kgaided as A shaped ; if a peak R falls where the depression between * VViiitorl) berg'' htifi reiioried some observations from • i i leaves bol.iml it, on terminating, a state of altered eontraetilitv. fibrillation
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