Clinical disorders of the heart beat : a handbook for practitioners and students / by Sir Thomas Lewis.

  • Lewis, Thomas, Sir, 1881-1945.
Date:
1925
Catalogue details

Licence: In copyright

Credit: Clinical disorders of the heart beat : a handbook for practitioners and students / by Sir Thomas Lewis. Source: Wellcome Collection.

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    frequently confined to the few cycles which follow a premature beat that in any class of the patients mentioned, it is important to obtain a curve which contains such a beat. This may often happen at the first examination. The patient should remain standing, for premature beats are more frequent in this posture, and if he has come some distance it is well that the examination should proceed at once, since premature beats are more conspicuous at such times and the pulse rate is higher. It should be remem¬ bered, too, that a held breadth may evoke a premature beat, and the opportunity of detecting alternation in this manner should not be lost. Single premature beats are usually followed by a pulsa¬ tion of exceptional size, for the heart puts out more than m % w mmw r-r » w sr~~y—v~sr~y—y <r * w ¥'•*'¥ p £ s' £' s1 Fig. 55. Alternation of the pulse, appearing after, and as a result of, a single premature beat p. It lasts for four heart cycles. its usual quantum of blood. It is the pulse which succeeds this tall beat that shows the first sign of weakening ; it is less forcible than that which succeeds it. In Fig. 55 a regular pulse is interrupted by a single premature con¬ traction (p) ; it is followed by the usual pause, and this is succeeded by a tall pulsation (l) ; the next beat sl is small, it is followed by a taller beat l1. The small beat s1 is, as I have said, the earliest sign of the condition, and it may be the sole sign. In the actual figure <s2, the next alternate beat, is also low. Alternation has proceeded for four cycles before the normal pulse beats are restored. In Figs. 53 and