Exceptional types of slow heart action / by Thomas Lewis.

  • Thomas Lewis
Date:
[1913]
Catalogue details

Licence: Public Domain Mark

Credit: Exceptional types of slow heart action / by Thomas Lewis. Source: Wellcome Collection.

    15/22 page 233
    EXPLANATION OF FIGURES. PLATE 14, Fie. 11. Electro-cardiograms from Case I, showing the three leads, J, right arm to left arm ; IJ, right arm to left leg ; and JZJ, left arm to left leg. In leads J and J/I the heart is beating regularly at a rate of 54 per minute. In lead JJ the heart is beating irregularly, but the beats are of the same nature, being generated in the sino-auricular node. The horizontal lines in this and subsequent figures divide spaces equivalent to 10-* volts. The time-marker is in wy seconds. Fies. 12-16. A series of curves from lead IZ from the same case; the lengths of the cycles are marked in thirtieths of seconds. Figs. 12 and 16 show three cycles in which auricle and ventricle respond to common and nodal impulses and two escaped contractions in which the ventricular beats are coincident with normal auricular contractions. Fig. 13. Three normal cycles are followed by two escaped contractions. Fig. 14 shows a single nodal beat followed by four normal cycles. Fig. 15 shows five nodal beats. PLATE 15, Fie.17. Electro-cardiograms from the three leads in Case II. In leads J and lI the action of the heart is regular, the rate being 44 per minute. In lead IJ the heart action is irregular. In all the curves the mechanism is similar ; the ventricular beats are of a supraven- tricular type and there is no sign either of a P summit or of the oscillations which characterize a fibrillating auricle. Fre. 18. An electro-cardiogram from Case III (lead ZZ), showing a bigeminal action of the ventricle. The first cycle of each couple consists of a normal sequential beat, the second beat of each couple is a premature beat, presumably arising from the left side of the heart. It differs from the beats known to originate in this neighbourhood in that it is notched. An inverted auricular complex follows with this anomalous ventricular complex and distorts it, as shown by the dotted line in the middle group of the figure. The figure illustrates retrograde heart-beats. The time-marker in this and Fig. 19 is in } sec. Fie. 19. An electro-cardiogram from the same case (lead I/), showing the heart-beats grouped in threes. The first and second beats of each group are similar to those of Fig. 18. The third beat of each group is also of ventricular origin but comes from different points in the two instances. No trace of auricular contraction can be found to complicate this third beat. A comparison may be made between the two premature ventricular contractions in the right-hand group ; the first of these is distorted by an inverted P, the second is not.
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