Diseases of the heart and aorta⁷

There is nothing about the duct on page 61! The text at this point deals with the motion of the dying heart and the propagation of cardiac movements!

Page 303 does, indeed, contain a description of the murmur as follows: “The most characteristic physical sign is the murmur in the second left intercostal space over the septum where the thrill is felt and this murmur is of late systolic rhythm, that is to say that when compared with the apex beat it distinctly follows it. The murmur is usually somewhat long in duration and of high pitched character; it is usually louder in inspiration.”

On pages 310 through 312, Gibson then describes 2 illustrative patients having patency of the arterial duct. When describing the first, he writes: “On auscultation a loud rough systolic murmur was heard everywhere throughout the thorax; in fact it was propagated as far as the knees and elbows, but its maximum intensity was in the second intercostals space, just at the point where the thrill could be felt most distinctly; and on careful auscultation with the hand over the apex beat, the murmur was distinctly later than the apex beat. It was, in short, what is commonly called a late systolic murmur.”

For the second patient, the description was: “On auscultation a loud murmur could be heard over most of the præcordia, but its maximum intensity was in the second intercostal space at the point where the thrill was most distinctly felt. The murmur distinctly followed the first sound and was continued after the second, and in the pulmonary area the second sound was considerably accentuated.”

Well, well! These accounts are nothing like the descriptions attributed to Gibson by our latter day authors, “rough” but not “rough and thrilling”, and certainly no “machinery”. The description of the much quoted “Gibson murmur”, therefore, is not to be found in the pages of his book. How about the Edinburgh Medical Journal.

Edinburgh Medical Journal⁸

His paper describes a patient with persistence of the arterial duct in whom the diagnosis was made in life, and who died of pneumonia. Both diagnoses were confirmed at autopsy. In the preamble to the case presentation, Gibson discusses the haemodynamics of the malformation, and the haemodynamic basis of the murmur. Interestingly, he also talks about the resistance of some of his contemporaries to basing such a diagnosis “largely upon murmurs”. Here is Gibson's description of the murmur.

“At the base of the heart an almost continuous rushing murmur is heard, beginning shortly after the first sound, which is quite clear at its commencement, and continuing almost to the beginning of the next first sound. It is best heard in the third left interspace about 2½ inches from midsternum, but is heard all over the base of the heart. The second sound is heard distinctly in the middle of the murmur; it is distinctly accentuated, and sometimes doubled.”

During the presentation on which the article was based, Gibson then drew the “rhythm of the murmur” on the blackboard. A similar drawing was included in the article (Fig. 2). Gibson said that, in the figure, “accentuation and doubling of the second sound in the pulmonary area are conventionally indicated”.

Figure 2. Gibson's graphic representation of the duct murmur from the Edinburgh Medical Journal of 1900.7

Now here's a state of things. None of the articles cited by our present day authors contains anything like, according to one of these authors, the “deservedly widely quoted” description. Since George Alexander Gibson read every paper he quoted, he deserves better from us.

I decided, therefore, to look at some more of his publications. In a book written for students, “Gibson and Russell's Physical Diagnosis”,⁹ the arterial duct is not even mentioned. Presumably it was too esoteric for students. But, in a lecture given in 1906,¹⁰ he gives this description of a murmur heard in a 24-year-old man: “It begins quite obviously after the commencement of the first sound. It is continued during the latter part of that sound and the whole of the short pause. It persists throughout the second sound and dies away gradually during the long pause. The murmur is distinctly rough and thrilling in its character. It begins, however, somewhat softly, and increases in intensity to reach its acme just about, or immediately after, the incidence of the second sound, and from that point wanes until its termination. The second sound can be heard to be loud and clanging and when carefully analysed it is the pulmonary part of that sound which is accentuated.”

This is a bit more like it. This lecture was essentially a case presentation with a discussion. The patient presented also had aortic stenosis and regurgitation, with their associated murmurs. The exhaustive description of the murmur emanating from the patent duct may have been given with the objective of differentiating it from the other two.

This certainly is a Gibson murmur, but is it the Gibson murmur? In his discussion, he refers to other cases. At the conclusion of the lecture, he summarises what he considers to be the pathognomonic murmur: “Beginning distinctly after the first sound, it accompanies the latter part of that sound, occupies the first pause, accompanies the second sound, which may be accentuated in the pulmonary area or may be doubled, and finally dies away during the long pause.” This, then, is the real Gibson murmur.

Incidentally, he was still having trouble with his contemporaries. He cites one as saying that his conclusions where not supported by autopsy evidence, despite the fact that he had presented such evidence in a previous publication.⁷

But who was responsible for stating that the murmur emanating from the patent duct of this particular patient was Gibson's pathognomonic murmur? To resolve this issue, I looked in some of the books from the 1950s relating to Paediatric Cardiology. In one, “Heart Disease in Infancy and Childhood”,¹¹ a book issuing from Toronto, I found essentially the same description as that given in our book “Paediatric Cardiology”, and in “Cardiac Surgery”, as quoted above. The citation was alleged to have originated in the Edinburgh Medical Journal of 1900. Now, the authors of both versions of the chapter in our book had worked, or were working, in Toronto. It occurred to me that the people in Toronto must have got their quotation from somewhere, albeit not directly from Gibson. Who were the real pioneers of Paediatric Cardiology? Helen Taussig and Maude Abbott. In Maude Abbott's book “The Diagnosis of Congenital Heart Disease”, published in 1928,¹² the murmur from the duct is described as: “a continuous” or “machinery” murmur first described by Gibson. After her own description of the murmur, she ends the paragraph. “In Dr Gibson's words” and provides a verbatim quotation of the description of the murmur in the 24-year-old man presented in the 1906 clinical lecture, including the “loud and clanging” second sound. She cites the reference as: “Gibson GA: Persistent ductus arteriosus. Edin. Med. J., n.s. viii and also Medical Press and Circ, Lond., May 30, 1906.”

So there we have it. Maude Abbott had obviously read both papers, but confused future authors by quoting the wrong one first! Some subsequent authors have quoted Abbott, and used her first reference, which was wrong. How the reference to “Diseases of the Heart and Aorta” got into the act has still to be determined!

During my quest, I have developed an admiration for George Gibson. He was a meticulous man. MacKenzie, in his eulogy, gives as an example of this. When Gibson wanted to cite a reference in Dutch, he learned enough of that language to understand the article. He was widely cultured, with skills in ancient and modern languages. As well as being a cardiologist and physiologist, he was a general physician, with an encyclopaedic knowledge of the field. His approach to young workers, and to innovative ideas, was open and welcoming. He was a consummate clinician and teacher, and a compassionate friend. One small thing endears him to me. He used the terms “ductus arteriosus” and “arterial duct” interchangeably, even though he, unlike most of us, would have known that the pleural of “ductus” is not “ducti”.

The incorrect citation of the references to the Gibson murmur is hardly a catastrophe, but should serve as a warning to readers and writers alike, reminding them to remain critical and sceptical. In future, always check the sources of your references. I do think that Gibson was done a potential disservice. His synthesis of his experience of ductal murmurs, as given at the conclusion of his lecture of 1906, applies to ducts with and without pulmonary hypertension, unlike the “widely quoted” version, where the patient most probably did have pulmonary hypertension.

In the chapter on patent ductus in our textbook “Paediatric Cardiology”,^{1, 2} the authors also state that Botallo described postnatal patency of the foramen ovale, or oval foramen, and not the arterial duct. They argue that, by a series of misinterpretations and careless translations, his name became, quite unjustifiably, attached to the arterial duct. Yet two major historical reference books^{13, 14} say that he rediscovered not only the foramen ovale, but also the arterial duct and its ligamentous remnant, the “ligamentum arteriosum”. But that is another story. Perhaps we people living in glass houses should be a little reluctant to throw stones?

Acknowledgements

I would like to thank Mr Iain Milne, librarian of the Royal College of Physicians of Edinburgh, and the librarians of the Royal Society of Medicine, for their unstinting help in preparing this article.