Structural diseases of the heart considered from the point of view of prognosis / by W.H. Broadbent.

  • Broadbent, W. H. (William Henry), Sir, 1835-1907.
Date:
[1891?]
Catalogue details

Licence: Public Domain Mark

Credit: Structural diseases of the heart considered from the point of view of prognosis / by W.H. Broadbent. Source: Wellcome Collection.

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    All these measiires are specially required when the hyper- trophy IS no longer quite equal to the task which it had originally been developed to perform, and the reduplication and other moditications of the sounds are present. It is now that the incidents of hypertrophy, palpitation, and the like, are most commonly complained of, and they will be best alleviated or removed by the measures just sketched out, by relieving the heart of work on the one hand, and by helping it on the other. Dilatation.—The word dilatation requires no explanation as applied to the cavities of the heart. Individual cavities may be dilated, as for example the left auricle in mitral stenosis or regurgitation, the right ventricle in pulmonary emphysema or mitral disease, but when spoken of as a form of heart disease, dilatation usually means dilatation of the left ven- tricle, mostly with, but sometimes without, dilatation of the right ventricle. Together with the expansion of the cavity of the ventricle there may be more or less thickening of its walls representing an attempt at hypertrophy, compensatory of the dilatation itself, or of the difficulty in the circulation which has led to it. Not infrequently the hypertrophy has preceded the dilatation. Or the walls of the heart may have an approximately normal thickness, which will really imply a certain degree of hypertrophy, or they may be distinctly thinned. The parietes may have a normal colour, consist- ence, and structure, or they may be pale, flabby, and degene- rated, or dense and tough from fibroid substitution. But even more important than the anatomical condition is the physiological or functional condition, the special character- istic of which is that the ventricle does not complete its systole, but only expels a portion of its contents. Dilatation of the heart may be contrasted with hypertrophy rather than compared with it. Hypertrophy is compensatory and an evidence of vigour in the heart; dilatation is, for the most part, a confession of failure on the part of the heart muscle and an aggravation of other causes of interference with the circulation which may be in operation. In hypertrophy the augmented mass and increased strength of the muscular walls enable the ventricles to complete their contraction in the face of difficulty. The result of dilatation is that the ven- tricles habitually fail to expel the whole of their contents. Very frequently it is only a very small proportion of the blood which is projected into the great arteries. In well marked cases the chambers of the heart are always full, and little blood being received and expelled there is a stagnation in the auricles and ventricles which may allow of the deposition of fibrin among the fleshy columns and pectinate muscles. It has seemed to me that the imperfect emptying of the ven- tricles has not always been fully realised as the special feature of dilatation, but it will be seen that if a dilated ven- tricle launched the whole of its contents into the arterial circulation, the amount being much larger, the rate of move- ment of blood would be greatly accelerated, whereas the con trary is the case. The dilatation attending aortic regurgitation belongs to a different category, and, instead of aggravating the difhculties of the circulation, it is a part of the compensatory arrange^- ment It is clear that if a certain proportion of the blood croiected into the aorta at each systole returns to tlie ven- tricle during diastole, it is an advantage, and indeed a neces- sity that the capacity of the ventricle should be increased,