Revised views of the refractory period, in relation to drugs reputed to prolong it, and in relation to circus movement / by T. Lewis and A.N. Drury.
- Thomas Lewis
- Date:
- [1926]
Licence: Public Domain Mark
Credit: Revised views of the refractory period, in relation to drugs reputed to prolong it, and in relation to circus movement / by T. Lewis and A.N. Drury. Source: Wellcome Collection.
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![[Reprinted from ‘‘ Heart.” Vol. XIII, No. 1, August, 1926.] REVISED VIEWS OF THE REFRACTORY PERIOD, IN RELATION TO DRUGS REPUTED TO PROLONG IT, AND IN RELATION TO CIRCUS MOVEMENT. By T. LEWIS and A. N. DRURY.* (from the Cardiac Department, University College Hospital Medical School). IN a series of articles from this laboratory circus movement has been discussed, and the actions of certain drugs, notably those affecting auricular fibrillation and flutter, have been explored. Related observations have been continued and further information has been obtained which places certain of the previous observations in a new light. We propose in the present communication briefly to revise the most important of these questions which are thus re- opened. The position as it now exists may be most conveniently shown by a short historical résumé of the more recent observations. Drury and Andrus? investigated the effects of hydrogen-ion concentration upon the muscle of the dog’s auricle perfused with Locke’s solution, and were able to bring forward evidence that a condition akin to decrement arises when the perfusate is on the acid side of normality and oxygen free. The condition is one in which an impulse is found to slow down as it travels through muscle, sometimes dying out completely. Drury,t who was simultaneously investigating the meaning of intra-auricular block produced by pressure or by cold, found that both these influences led to a similar anomaly of conduction. More important from our present standpoint, he found that the phenomenon in question may seriously interfere with the accurate measurement of absolute refractory periods ; failure of muscle to respond to an‘early testing shock, may be more apparent than real ; for, while the muscle may actually respond, the excitation wave so started may die out before reaching a distant point at which the recording electrodes lie. Owing to similarities in the conduction of impulses through muscle compressed and cooled and muscle under the influence of quinidine and strophanthin, the question arose as to whether a similar disappearance of very early excitation waves might not happen in shorter stretches of muscle, and in consequence prolong the estimate of the refractory period of muscle affected by these drugs. * Working on behalf of the Medical Research Council.](https://iiif.wellcomecollection.org/image/b33430524_0003.jp2/full/800%2C/0/default.jpg)
