Medical Terminology Daily - Est. 2012

Medical Terminology Daily (MTD) is a blog sponsored by Clinical Anatomy Associates, Inc. as a service to the medical community. We post anatomical, medical or surgical terms, their meaning and usage, as well as biographical notes on anatomists, surgeons, and researchers through the ages. Be warned that some of the images used depict human anatomical specimens.

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A Moment in History

Jean George Bachman

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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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.

William Harvey
William Harvey

William Harvey (1578 - 1609) English physician, physiologist, and anatomist. He was born in Folklestone, where his  father was the mayor.

Harvey studied at the King’s College in Canterbury, after which he entered Cambridge. He later traveled through France and Italy and continued his studies in Padua, where he graduated with an MD in 1602. He later returned to Cambridge to complete his Doctoral studies.

He became the Physician-In-Charge at St. Bartholomew’s Hospital.  It was at this time that he started a long process of scientific observation and logical reasoning that led him to postulate the circulation of the blood in his 1628 publication  "Excercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus"  (Anatomical Exercises on the Movement of the Heart and the Blood in Animals).

Harvey’s publication caused incredible controversy, as his proposed theory went against Galen’s theories and the idea that blood passed through "invisible pores" from the right to the left atrium of the heart. His main problem was that he could not prove the presence of capillaries, which were not observed until Antoine van Leeuwenhoek invented the microscope in the late 1600's.

In his book Harvey states ''It is absolutely necessary to conclude that the blood in the animal body is impelled as in a circle and is in a state of ceaseless motion: that this is the act or function which the heart performs by means of the pulse, and that it is the sole and only end of the motion and contraction of the heart”. Even today there are many that use the term “circulatory system” without realizing that the meaning “as in a circle” coined by William Harvey is present in it.

Although the first to consider the term “circulation” was Michael Servetus (1511 – 1553), his ideas were not completely evolved. Had he completed his research and studies Servetus could have precluded Harvey, but he was considered a heretic and burnt at the stake. Thankfully, Harvey was not!  

Sources:
1. "William Harvey"Billimoria, A.  J Assoc Phys 60 (2012) 57
2.  “William Harvey” Foucar, HO. Can Med Assoc J 1951; 64(5): 452–453.
3. “William Harvey” McKecnie, EDJ, Robertson, C.  Resuscitation 55 (2002) 133-136
4. “William Harvey, an Aristotelian anatomist” Fara, P. Endeavour 21:2 (2007) 43–44
5. “The life and work of William Harvey” Keele, KD Endeavour 2:3 (1978) 104–107
Original image in the Public Domain. Courtesy of the National Library of Medicine