John Marshall

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A Moment in History

Jean George Bachmann
(1877 – 1959)

French physician–physiologist whose experimental work in the early twentieth century provided the first clear functional description of a preferential interatrial conduction pathway. This structure, eponymically named “Bachmann’s bundle”, plays a central role in normal atrial activation and in the pathophysiology of interatrial block and atrial arrhythmias.

As a young man, Bachmann served as a merchant sailor, crossing the Atlantic multiple times. He emigrated to the United States in 1902 and earned his medical degree at the top of his class from Jefferson Medical College in Philadelphia in 1907. He stayed at this Medical College as a demonstrator and physiologist. In 1910, he joined Emory University in Atlanta. Between 1917 -1918 he served as a medical officer in the US Army. He retired from Emory in 1947 and continued his private medical practice until his death in 1959.

On the personal side, Bachmann was a man of many talents: a polyglot, he was fluent in German, French, Spanish and English. He was a chef in his own right and occasionally worked as a chef in international hotels. In fact, he paid his tuition at Jefferson Medical College, working both as a chef and as a language tutor.

The intrinsic cardiac conduction system was a major focus of cardiovascular research in the late nineteenth and early twentieth centuries. The atrioventricular (AV) node was discovered and described by Sunao Tawara and Karl Albert Aschoff in 1906, and the sinoatrial node by Arthur Keith and Martin Flack in 1907.

While the connections that distribute the electrical impulse from the AV node to the ventricles were known through the works of Wilhelm His Jr, in 1893 and Jan Evangelista Purkinje in 1839, the mechanism by which electrical impulses spread between the atria remained uncertain.

In 1916 Bachmann published a paper titled “The Inter-Auricular Time Interval” in the American Journal of Physiology. Bachmann measured activation times between the right and left atria and demonstrated that interruption of a distinct anterior interatrial muscular band resulted in delayed left atrial activation. He concluded that this band constituted the principal route for rapid interatrial conduction.

Subsequent anatomical and electrophysiological studies confirmed the importance of the structure described by Bachmann, which came to bear his name. Bachmann’s bundle is now recognized as a key determinant of atrial activation patterns, and its dysfunction is associated with interatrial block, atrial fibrillation, and abnormal P-wave morphology. His work remains foundational in both basic cardiac anatomy and clinical electrophysiology.

Sources and references
1. Bachmann G. “The inter-auricular time interval”. Am J Physiol. 1916;41:309–320.
2. Hurst JW. “Profiles in Cardiology: Jean George Bachmann (1877–1959)”. Clin Cardiol. 1987;10:185–187.
3. Lemery R, Guiraudon G, Veinot JP. “Anatomic description of Bachmann’s bundle and its relation to the atrial septum”. Am J Cardiol. 2003;91:148–152.
4. "Remembering the canonical discoverers of the core components of the mammalian cardiac conduction system: Keith and Flack, Aschoff and Tawara, His, and Purkinje" Icilio Cavero and Henry Holzgrefe Advances in Physiology Education 2022 46:4, 549-579.
5. Knol WG, de Vos CB, Crijns HJGM, et al. “The Bachmann bundle and interatrial conduction” Heart Rhythm. 2019;16:127–133.
6. “Iatrogenic biatrial flutter. The role of the Bachmann’s bundle” Constán E.; García F., Linde, A.. Complejo Hospitalario de Jaén, Jaén. Spain
7. Keith A, Flack M. The form and nature of the muscular connections between the primary divisions of the vertebrate heart. J Anat Physiol 41: 172–189, 1907.

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Details: Written by: Efrain A. Miranda, Ph.D.; Published: October 09, 2024; Hits: 1182

This article is part of the series "A Moment in History" where we honor those who have contributed to the growth of medical knowledge in the areas of anatomy, medicine, surgery, and medical research.

John Marshall (1818 – 1891)

John Marshall (1818 – 1891) British anatomist and surgeon. Initially, he apprenticed with Dr. Wales in Wisbech. In 1838 he entered the University College, London, where he studied with William Sharpey (1802 – 1880), who was then teaching physiology. In 1849 Marshall became a Fellow of the Royal College of Surgeons of England.

In 1845 he became a demonstrator of anatomy at University College, London and in 1847 with the help of Jones Quain (1796 – 1865) and William Sharpey he was appointed as assistant surgeon.

Marshall was appointed professor of surgery at University College in 1866, and in 1884 he was appointed consulting surgeon to University College Hospital.

He was known as a great artist and used his abilities to teach anatomy with the help of blackboards. He lectured on anatomy to art students, and one of his books is titled “Anatomy for Artists” (London, 1878), which was received with great enthusiasm by his art students.

John Marshall wrote several books and works, mentioned in the “Sources” section of this article, but he is probably better known for his association with the eponymic “Ligament of Marshall”. In 1850, he published a detailed description (36 pages) of the embryology of the cardinal veins, the superior vena cava, and the presence of a persistent “left superior vena cava” with a description of the oblique vein of the left atrium, the obliterated Duct of Cuvier, and the fold of pericardium over this duct that today carries his name.

The paper was published in the journal “Philosophical Transactions of the Royal Society”, and the title was “On the Development of the Great Anterior Veins Man and Mammalia; including an Account of certain remnants of Fœtal Structure found in the Adult, a Comparative View of these Great Veins the different and an Analysis of their occasional peculiarities in the Human Subject”. The sketches that accompany this seminal paper were drawn by him.

If you are interested in reading this paper, it is available online at the Royal Society website. For the actual publication in PDF format, click here.

Marshall also is recognized for being one of the first to use electrocautery in surgery, as well as being a pioneer in the removal of lower extremity varicose veins. He was the first to demonstrate that cholera can be spread through contaminated drinking water.

The image shows the ligament of Marshall (yellow arrow), the left pulmonary artery (LPA), and the left superior pulmonary vein (LSPV).

Personal note: My thanks to an attendee to one of my cardiovascular lectures. He asked who was Marshall of the "ligament of Marshall:... Here is the answer. Dr. Miranda.

Sources and publications:
1. “A Description of the Human Body, its Structure and Functions” London, 1860, 4to, with folio plates; 4th ed. 1883.
2. “Anatomy for Artists” London, 1878, royal 8vo; 2nd ed. 1883; 3rd edit. 1890.
3. “A Rule of Proportion for the Human Figure” 1878, fol.
4 “A Series of Life-size Anatomical Diagrams” seven sheets.
5. “Physiological Diagrams” life size, eleven sheets.
6. “On the Relations between the Weight of the Brain and its Parts, and the Stature and Mass of the Body” 1892, J Anat Physiol
7. “The Brain of the late George Grote” 1892, J Anat Phys
8. “On the Development of the Great Anterior Veins Man and Mammalia; including an Account of certain remnants of Fœtal Structure found in the Adult, a Comparative View of these Great Veins the different and an Analysis of their occasional peculiarities in the Human Subject” 1850 Phil Trans R Soc 140:133 - 170
9. Portrait of J. Marshall by Alphonse Legros, Courtesy of Wikipedia. Public Domain.

John Marshall

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