67 Textbook of Medicine, vol. i., Am. ed.
68 Virchow's Archiv, lxxiv.
SYMPTOMS AND PHYSICAL SIGNS.—Dilatation produces weakness of the cardiac walls, diminishes the vigor of their contractions, and is thus the very reverse of hypertrophy. So long as compensation is maintained the enlargement of a cavity may be considerable: the limit is reached when the hypertrophied walls can no longer in the systole expel all the contents, part of which remain, so that at each diastole the chamber is abnormally full. Thus in aortic incompetency blood enters the left ventricle from the aorta as well as the auricle, dilatation ensues, and also hypertrophy as a direct effect of the increased pressure and increased amount of blood to move. But if from any cause the hypertrophy weakens, and the ventricle during systole does not empty itself completely, a still larger amount is in it at the end of each diastole, and the dilatation becomes greater. The amount remaining after systole is a cause of obstruction, preventing the blood entering freely from the auricle. Incompetency of the auriculo-ventricular valves follows with dilatation of the auricle and impeded blood-flow in the pulmonary veins. Dilatation and hypertrophy of the right heart may compensate for a time, but when this fails stasis occurs in the venous system, with dropsy. The consideration of the symptoms of chronic valvular lesions is largely that of dilatation and its effects. Acute dilatation, such as we see in fevers or in sudden failure of an hypertrophied heart, is accompanied by three chief symptoms—weak usually rapid impulse, dyspnoea, and signs of obstructed venous circulation. Cardiac pain may be present, but it is often absent.
The physical signs of dilatation are those of a weak and enlarged organ. The impulse is diffuse, often undulatory, and is felt over a wide area, and an apex-beat or a point of maximum intensity may not exist. When it does it may be visible, and yet cannot be felt—an observation of Walshe's which is very valuable. An extensive area of impulse with a quick, weak maximum apex-beat may be present. When the right heart is chiefly dilated the left may be pushed over so as to occupy a much less extensive area in the front of the heart, and the true apex-beat is not felt; but the chief impulse is just below or to the right of the xiphoid cartilage, and there is a wavy pulsation in the fourth, fifth, and sixth interspaces to the left of the sternum. In extreme dilatation of the right auricle a pulsation can sometimes be seen in the third right interspace close to the sternum, and with free tricuspid regurgitation this may be systolic in character. Whether the pulsation frequently seen in the second left interspace is ever due to a dilated left auricle is not satisfactorily determined. I have sometimes thought it was presystolic in rhythm, though it may be distinctly systolic. Post-mortem, it is rare in the most extreme distension to see the auricular appendix so far forward as to warrant the belief that it could beat against the second interspace. The area of dulness is increased, but an emphysematous lung or the full distended organ in a state of brown induration may cover over the heart and limit greatly the extent. The directions of increase were considered when speaking of Hypertrophy with dilatation.
The first sound is shorter, sharper, and more valvular in character, and more like the second. As the dilatation becomes excessive it gets weaker. Reduplication is not common, but occasionally differences may be heard in the joint sound over the right and left hearts. Murmurs very frequently obscure the sounds; they are produced by incompetency of the valves due to the great dilatation, or are associated with the chronic valve disease on which the condition depends. The aortic second sound is replaced by a murmur in aortic regurgitation; the pulmonary is accentuated in mitral regurgitation and pulmonary congestion, but with extreme dilatation it may be much weakened. The heart's action is irregular and intermittent, and the pulse is small, weak, and quick.
The DIAGNOSIS is generally easy when the physical signs, the history, and the general condition are taken into account. In a case of valvular disease with hypertrophy the onset of dyspnoea and venous stasis with dropsy tell unmistakably of cardiac dilatation. Increased præcordial dulness, with a weak, diffuse impulse, is not simulated by many conditions, and one only, pericardial effusion, need be specially mentioned. This may present very serious difficulties, and indeed a dilated heart has been aspirated under the belief that effusion was present. The points to be attended to are—the greater lateral dulness in dilatation and the wavy impulse which may extend over a great part of it; in effusion the dulness extends upward and is more pear-shaped, the impulse is not so extensive, and may be tilted up an interspace or may not be visible. The sounds in pericardial effusion are muffled and distant over the dull region, but at its upper limit may be clear. The absence of friction is an important negative sign. In some cases it is extremely difficult to determine between the conditions, and I have known a weak, feeble, irregular heart, with cyanosis, and oedema lead to the diagnosis of dilatation when effusion was present.
The PROGNOSIS depends upon the cause of the dilatation. In anæmia and fevers the temporary dilatation may undoubtedly pass away with the improvement of health; but when the cause is not remediable the danger must be measured by the presence or absence of compensation. In the majority of the cases which we see the dilatation occurs in valve disease, and no symptoms of importance arise so long as the compensation is perfect. Failure of this, which may result from many causes, as already mentioned, is always serious. It may be only temporary, and with care the compensation can be re-established and the symptoms pass away. We constantly see this in the eccentric hypertrophy of the right heart from mitral disease; an attack of bronchitis suffices to disturb the compensation, and with the relief of the catarrhal trouble the dyspnoea and heart symptoms disappear.
The TREATMENT of dilatation is virtually that of chronic valvular disease, and we shall only refer to general indications. With the earliest symptoms of failure the work of the heart should be reduced to a minimum by placing the patient at rest. This in itself may suffice without any other measures. Time and again I have seen, particularly in cases of aortic insufficiency, the dyspnoea relieved and the oedema of the feet disappear and the compensation re-established by placing the patient in bed, enjoining absolute quiet and carefully regulating the diet. The importance of rest in the early stages of heart failure cannot be too much insisted upon.69 Quiet and careful dieting may suffice for the milder attacks, but we have usually even in these to resort to heart tonics. Digitalis is the most powerful remedy we possess in restoring and maintaining compensation. Under its use the irregular, feeble, and frequent contraction becomes regular and stronger, and the embarrassed circulation is relieved. In hospital practice the same chronic heart cases may return year after year with attacks of cardiac failure, dyspnoea, dropsy, etc., and each time the rest in bed and digitalis may suffice to restore compensation. A fourth or fifth, even a sixth, attack may be safely weathered, and then the final breakdown occurs when nothing avails to combat the dilatation. Of substitutes for digitalis, caffeine and convallaria have been much used of late. Caffeine in some cases acts more promptly, which is an advantage, but its action is not so certain and not so enduring. Convallaria is very variable in its action; it has succeeded in some instances in which digitalis has failed, and in others has been quite without effect. In extreme cardiac failure with great dilatation, lividity, orthopnoea, and feeble pulse, stimulants must be freely given; ether may be employed hypodermically. In this condition of final asystolism digitalis seems to have lost its influence. In the heart failure of pneumonia I have found camphor a valuable adjuvant to the diffusible stimulants. To improve the general nutrition, and with it that of the heart-muscle, iron and arsenic are most valuable adjuvants, especially in the dilatation of anæmia. The treatment of special symptoms, dropsy, dyspnoea, etc., is considered under Valvular Affections.
69 In Ortel's system (Ziemssen's Handbuch der Allgemeine Therapie, Bd. iv.) of treating heart disease exercise, particularly climbing, forms a very important part, but an analysis of his cases shows that most of them were instances of fatty heart in obese persons. It would scarcely be applicable to valvular disease. The severe exercise, he thinks, stimulates the heart-muscle and helps in the restoration of the hypertrophy. His other suggestion, the reduction of the liquids ingested, seems much more reasonable, as in this way the volume of blood to be circulated may be considerably reduced.
Aneurism of the Heart.