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The ventricle continues in diastole for two or more strokes of the systole of its auricle, and then relieves itself by a prolonged effort; it is like a smith who, striking at the forge a number of strokes in rhythmical succession until tired, changes the action for a moment to give a more deliberate and determinate blow, and then rings on again in regular time.
This no doubt is true in relation to the left ventricle, but is the failure confined to the left ventricle as originally assumed, or do both right and left ventricles fail ? I am now of opinion that both ventricles fail, and that the order of change from the natural through the unnatural and again to the natural is as follows.
The ventricles, filled by the systole of the auricles, fail to contract on the blood contained in them; thus the system altogether is left with the arterial side of the heart full, with the arteries contracted on a small column of blood, with the veins full, and with the right side of the heart full both in auricle and ventricle. In a word, the whole circulating system is left containing blood, so that the line of the blood current continues unbroken. During the interval of the cessation of the action of the ventricles, blood is, moreover, still entering the right auricle from the two cavæ, by that continuous force which the older writers called the vis a fronte, and the auricle remains in motion, contracting on its contained blood. A column of blood is in this way still carried into the pulmonary artery, and, the artery contracting, a feeble second sound is produced, after the loss of the systolic sound, by the closure of the pulmonary semilunar valves. Lastly, when the ventricles again contract, contracting as they do at this time on a double charge of blood, there is produced the long heavy systolic sound, followed by the two sharp faint second sounds, the reduplication of the second sound being dụe either to a separate
closure of the pulmonary and aortic sets of valves, or to a simultaneous double but feeble closure of both.
Organic Cause of Intermittent Pulse. In the above explanations I have dealt simply with the mechanical cause of the abnormal phenomenon of intermittency of the pulse. Now arises the question-what is the more elementary, the organic, cause? Let us study this question by the process of exclusion.
We should naturally begin by looking into the structure of the heart for a cause. We should be wrong. The fact alone that during the intervening periods of intermittency the heart is natural in its action, would go far to indicate that in it there need be no serious organic lesion. Still, this of itself would be little were it unsupported by more direct evidence. Being greatly interested in this matter, I seized once the opportunity of examining after death the heart of an aged man, who for many years presented the phenomenon of intermittency more determinately than I ever before had seen; his pulse, never, as far as I could learn, failed to intermit less often than once in eight beats. His death was from senile decay, but his circulation may be said to have outlived all the other of his systemic powers. When quite insensible, the pulse with long hesitations, came up again, and the pulse was beating at the end, even when the respiration had ceased. After death, instead of a diseased heart, the heart was found the healthiest of the organs of the body. There was no trace of valvular dis
There was no departure from the natural size and condition of the cavities or the thicknesses of the walls; the coronary arteries were normal, and the muscular structure, quite free from fatty and granular degeneracy, was merely, as the tissues are in the aged, a shade paler than is common in the young and robust. Since the occurrence of that case, I have confirmed the experience then gained by three other expeperiences. I feel bound, therefore, to say, from what I have seen, as positive truth, that the most marked intermittency of the heart may be present without evidence of any known form of organic disease of the organ itself; and, as one fact carefully assured is as good as a thousand, I am driven to accept that there is no known morbid condition of the heart itself, structurally considered, that produces the phenomenon of intermittent action. Intermittency may co-exist with other signs of cardiac derangement essentially of structural origin ;,a fatty heart may intermit; a heart with faulty valvular mechanism may intermit; and intermittency with structural change may form, and often does form, a most serious complication. These facts we must at once allow, but we must allow them feeling that the intermittent action, having no necessary connection with the structural disorder, is evoked by a cause remote and independent. Pre-existent diseases of a special kind, such as acute rheumatism, do not, so far as I can learn, leave intermittency specially in their train ; neither, as far as I know, is the phenomenon more common in those who have structural disease of the heart than in those who have not.
From the study of the heart itself we may turn naturally to the digestive system, and ask if there can be any cause for the symptom in functional or organic disease there ? May not the symptom, that is to say, be due to some one of the many forms of dyspepsia ? On this point my observations lead me to assume that intermittency of the heart has no relation to what is commonly called “ dyspepsia.” It is true that many dyspeptic persons have intermittent pulse, but this fact does not affect the question, because it is equally true that many persons who have determinate intermittency of pulse have the most keen and excellent digestion. I have a patient at this very time whose case is strictly in point: his pulse intermits every sixteenth beat, but his tongue is clean, his urine natural, his appetite good, his sleep sound, and his bowels regular. After taking food he has no pain, he has no flatulency, and, according to his own often repeated expression," he does not know that he has a stomach.” On the other hand, we constantly see dyspepsia in all its varied and severe forms without the sign of intermittency.
In publishing for the first time on this subject I held, as above, that dyspepsia has no necessary relation to the prime cause of intermittency, and although Dr. Leared and some other learned friends, for whose opinion I have the greatest regard, have disputed the position, I am forced to re-affirm it. I admit that many persons who are dyspeptic have intermittency of the pulse, and I believe there are cases in which dyspepsia itself is due to some similar cause as that which is at work to induce intermittent action; so that the two symptoms running together, the one, unless the analysis be searching, may seem to stand in relation either of cause or of effect to the other, whereas they are simply co-incident symptoms. Further, I am quite willing to allow that in persons who have what may be correctly called “recurring intermittency,” the recurrence may, and indeed often does, present itself with symptoms of dyspepsia. Further still, it is I think possible that in those who are disposed to intermittent pulse, an attack of dyspepsia may, by the irritation and deprivation of general power which it induces, aggravate the symptom of intermittency. But this is the position I accept, nature leading me to it,—that amongst the large number of persons who have intermittent pulse none owe it simply to dyspepsia ; that its cause lies beyond dyspepsia even in the dyspeptic, and that it may be present in its most aggravated form when dyspepsia does not exist at all.
I know of no diseased condition of the blood with which the phenomenon of intermittency is connected. Neither have I been able, after careful research, to trace it, in the light of
effect from cause, to any affection of the lung, the liver, the kidney, or other secreting or excreting organ.
Thus we are driven at last to one sole system of the body in which to seek for the origin of the phenomenon of intermittency of the heart; and that is the nervous system. Followed to this seat, all the evidence is too unequivocal to be doubted. The frequent sudden development of the phenomenon, its purely functional character, in so far as the heart is concerned, and the other symptoms by which it is attended, leave no room to question the correctness of the view that the momentary cessation of the ventricular systole occurs from deprivation of or opposition to the nervous force by which the ventricles are enabled, under the stimulus of the blood thrown into them by the auricles, to contract upon and regulate the blood currents in their
All the evidences, again, point to the fact that, in every case of true intermittency, one particular point or centre of the nervous system is the primary seat of the derangement. The phenomenon is too uniform to admit of any explanation less definite; it speaks to us and says that either there is deficiency of force in the centre of the nervous system which provides for ventricular contraction, or there is some centre which balances or controls that supplying centre, and which, rendered overactive from irritation, is interfering with contraction.
The derangement might be in the ganglionic centres of the heart itself; but if it were, the nutrition of the organ would surely be more decidedly influenced, and the cardiac symptoms would not be intermittent, but persistent. The derangement might be from irritation in the periphery or in the branches of the pneumogastric ; but if it were, it would hardly be continuous for years, with no other sign of muscular disturbance. Where then is the primary mischief? I believe it to be in some mental centre of the nervous system. The clinical history of every case I have seen points to that truth. In the aged, in