The study of the pulse : arterial, venous, and hepatic, and of the movements of the heart / by James Mackenzie.

  • James Mackenzie
Date:
1902
Catalogue details

Licence: In copyright

Credit: The study of the pulse : arterial, venous, and hepatic, and of the movements of the heart / by James Mackenzie. Source: Wellcome Collection.

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

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    a smaller systolic wave s' occurs in the tracing of the ventricular pressure. This wave is not so forcible, and causes only a slight wave s' in the aortic tracing. Following this imperfect wave there is a long pause terminated by the appearance of another full systolic beat. Following the second full ventricular systole is another early occuring imperfect beat s', which makes but a slight impression s' on the aortic tracing. This imperfect systole is followed by another imperfect systole s, but so weak is it that it does not affect the aortic pressure. From such a tracing as this it can be inferred that in the pulse tracing, Fig. 61, the small pulse wave was due to an early occurring systole, so weak that it was unable to propagate a full pulse wave. When the ventricular systole is so weak that it fails to raise the aortic valves, as in the case of the wave s, Fig 62, we have a missed beat. The occurrence of an ineffective ventricular systole is well seen in Fig. 63. Here also the ventricular and aortic pressures were Fro. 63. Simultaneous tracings of the ventricular and aortic pressures, showing early weak ventricular systoles. The dotted line represents the height the ventricular pressure has to reach before the aortic valves can be opened (Marey).is registered simultaneously. The dotted line shows the height the ventricular pressure has to reach before the aortic valves can be opened. Every second beat of the ventricle is so slight that it fails to reach the height necessary to open the aortic valves, and consequently there is no sign of its presence in the aortic tracings. From these two figures it is seen that the small imperfect beat of an irregular pulse is due to an incomplete ventricular systole, and that when there is a missed beat it is due to the inability of the imperfect ventricular systole to overcome the aortic pressure.