On the influence of the position of the body on the position of the heart and on intracardiac pressure / by C.J. Bond.

  • Bond, C. J. (Charles John), 1856-1939.
Date:
[1885]
Catalogue details

Licence: Public Domain Mark

Credit: On the influence of the position of the body on the position of the heart and on intracardiac pressure / by C.J. Bond. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    I Tracing No. \.-(Contii uul) Sittinc/ u/j JProne Tracing No. 2.—(Continued.) irregular ; also (and this is very important) that the smaller frequenl rises are more marked during expiration than inspiration, owing to the iieart fallingback towards the spine during expiration; further, that these cardiae curves are very marked, especially on the summits of the ex- Tlae the left end of the tracing, while I was lying on my back, with the head and shoulders depressed, and legs and pelvis raised while they almost disappear in the sitting up and prone positions, tc positicm' at n®bt hand end of the tracing in the supine Now, in interpreting this tracing, we must remember that the base of the heart is in elose contact with the oesophagus, and loosely con- nected to it m the , olio wing way. It passes vertically down behind the left auricle, about midway between the right and left pulmonary veins, and is also in contact (the pericardium intervening) with a portion of the base of the left ventricle. That this cardiac tracing is really due to the movements of the base ot the heart, and not to pulsation in the pulmonary artery or large vessels, is shown by the fact that it varies with inspiration and ex- piration, and oeases entirely when the heart is drawn up a little from the spinal column by a sharp hook thrust into the apex. How, the iact that this eardiac eurve varies in intensity constantly with altera- tions in bodily position shows that the base of the heart (the amount of suspension m fact, of the organ) is influenced by bodily position. I he base, in fact, is pushed back or squeezed in inversion, the supine position, and in forcible expiration, while it is released in standing the rnrone position, and in full inspiration.. Further, the rise of the lever in this, the base-beat of the heart, is synchronous (as shown by direct observation, the pericardium being opened) with the ventricular sys- tole ; showing, in fact, that, as at the apex, so at the base, the heart at systole communicates a shock to the structures in contact with it; and, as this is transmitted through the left auricle, it favours Fick’s view of the function of the auricles—namely, to keep the venous flow constant, the intra-auricular pressure only rising appreciably at the ventricular systole by communication of shock and tension. At any rate, the fact of this “base-beat” being synchronous with the apex- beat seems to show that, partly by the tilting of the heart, an impulse is produced during systole at both base and apex, and that, consequently, the base of the heart does not descend or pass forward from the spine during systole, to any great extent, in consequence of the elongation of the large vessels, as has been supposed. Having thus proved that the heart moves on the base in the aS ^be body alters its position, we have next to consider whether this movement of the heart exercises any influence on the intracardiac blood-pressure, and if so, to what extent. A flexible tube, filled with solution of carbonate of soda, was passed down the external jugular vein of a dog (fully narcotised with ether) into the commencement of the right auricle, and connected with the tambour system above described, also filled with the solution. Tracing No. 3 shows the results obtained, starting on the right, with the animal lying on its baek. As it is rolled over to its left side, the intra-auricular pressure gradually falls, as shown by the descent of the lever ; this fall continues for a little time after the animal is replaced, but rapidly rises when the animal is held with the hind parts raised, and falls again when the pelvis is lowered, and the fore part of the body is elevated. * This effect varies constantly with bodily position, and is not due to I