Open AccessThe rhythm of the heart beat. I—Location, action potential, and electrical excitability of the pacemaker
Author(s) -
John C. Eccles,
H. E. Hoff
Publication year - 1934
Publication title -
proceedings of the royal society of london. series b, containing papers of a biological character
Language(s) - English
Resource type - Journals
eISSN - 2053-9185
pISSN - 0950-1193
DOI - 10.1098/rspb.1934.0042
Subject(s) - rhythm , beat (acoustics) , stimulus (psychology) , ventricle , diastole , auricle , cardiology , stimulation , neuroscience , medicine , sinus rhythm , anatomy , psychology , physics , cognitive psychology , acoustics , atrial fibrillation , blood pressure
Anatomical and physiological investigations on the heart during the last fifty years have contributed a sound body of knowledge concerning the location of its rhythmic centre (the pacemaker) and tire spread thence of excitation, The classical controversy between the exponents of the neurogenic view and of the myogenic view of the origin of the heart beat, may now be regarded as settled in favour of the latter, for the evidence against even the nerve fibre modification of the neurogenic theory is overwhelming, and none of the evidence supporting it stands the test of modern criticism, There remains the more fundamental problem of the nature of those processes in the rhythm centre which are responsible for its recurrent discharge. There has been much speculation concerning them, but no systematic attempt at elucidation. Engelmann (1895, 1897) postulated a constant weak "inner stimulus," to which the centre is sensitive in varying degree; this sensitivity (considered to be identical with its sensitivity to electrical stimulation) gradually increases during diastole, until a threshold is reached and discharge occurs. Gaskell (1900, p. 190) expressed an essentially similar view (cf . Adrian, 1930), and this view has some support in the evidence of Ishikawa (1924), who found that the excitability of the frog's sinus, but not of ventricle or auricle, increases throughout diastole until the next beat occurs. Langendorff (1902) suggested that the inner stimulus might be provided by the products of dissimilation (Lebensprodukt).