Certain clinical features of cardiac disease / by G. A. Gibson.

  • Gibson George Alexander, 1854-1913.
Date:
1908
Catalogue details

Licence: In copyright

Credit: Certain clinical features of cardiac disease / by G. A. Gibson. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    [363] septum, the branches of the bundle radiate outwards in every direction, and are continued as the Purkinje fibers which reach not merely the central portion of the long scroll of mus- cular tissue described by J.B.MacCalkm, but also the musculi papillares. The later investigations of Keith have not merely amplified certain details of this arrangement of fibers, but have furnished an altogether new and most interesting addition to our Icnowledge. Keith has recently shown that at the junction of the sinus and auricle of the right heart there is a peculiar structure, consisting of undifferentiated muscular'tissue con- taining a large number of nerve ganglia and nerve fibers. Gaskell not only analyzed the functions of the heart wall, pointing out that it possessed rhythmicity, conductivity, ex- citability, contractility, and tonicity, but he showed that there was a natural block at the auriculo-ventricular junction— often since termed Gaskell’s bridge ”—and he further brought the fact into pi*ominence that this block could be in- creased by artificial means. His discovered that by section of the auriculo-ventricular bundle impulses could be partially or totally inteiTupted in their passage downwards. Erlanger, while attached to the Johns Hopkins University, introduced a most ingenious method of exerting pressure upon the bundle and discovered that every degree of block might be produced. Bradycardia or abnormal infrequency of pulsation may be false or true; the former brought about simply by failure of some of the ventricular impulses to reach the periphery, so that the rate of the arterial pulse is less than that of the heart; the latter produced by infrequency of the heart itself. False bradycardia may be regarded simply as an expression of car- diac failure, and it is not my intention to deal with it on this occasion. True bradycardia may be total or partial; to the first group belong cases in which the entire heart, auricular as well as ventricular, participates in the reduced rate. In- stances of pressiire upon the vago-accessory fibers, of toxic infiuences affecting the nervous mechanism or the muscular structure, and degenerative changes affecting the heart wall are familiar instances in point. From the examination of the veins of the neck, of the peripheral arteries, and of the cardiac apex by the graphic method with simultaneous tracings, as