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the stethoscope in the left coat pocket surrendering the dominant right pocket to the tendon hammer( which I had to use much more often). Nevertheless, I kept my stethoscope handy, mainly for detection of carotid bruits and cardiac murmurs in patients presenting with stroke. Imagine the thrill of making a diagnosis of“ paradoxical embolism” in a young stroke patient, simply by detection of the presence of ASD by cardiac auscultation. The stethoscope continued to provide auditory treats although much less often; let me share with you just two such instances. I saw a 25-year-old with the complaints of diplopia and a“ swishing sound” in the head of several month’ s duration; he had also dislocated his shoulders many times in the past( could“ put it back” himself most of the time). Examination showed a right pulsating exophthalmos. It was an auscultatory“ dulcis” to hear the“ swish and hiss” murmur over the eye, diagnostic of a carotid-cavernous fistula. With the history of recurrent shoulder dislocation I wondered whether he may have a form of Ehlers Danlos syndrome, which can at times be associated with vascular problems including carotid-cavernous fistula.
Until a few years ago, I thought I had heard all that my stethoscope could offer but then came a pleasant surprise. A 50-year-old female was sent to me for electrodiagnostic work up for polyneuropathy, with a rather peculiar complaint. She tended to feel totally out of balance if standing for a few minutes, but could avoid falling just by touching an object or by walking. She religiously avoided situations where she would have to stand in a queue and was quite disappointed that she could not travel, leery of the long lines at the security clearance( she did not like wheelchairs!). I recalled reading a paper describing a similar patient and recorded a surface EMG to visualize the muscle activity in the legs when she stands. A high frequency tremor was detected, leading to the unconventional use of the stethoscope to clinch the diagnosis( by auscultating over the calf muscle and documenting the presence of the“ helicopter sound”( the auditory signature of the high frequency tremor). The diagnosis of primary orthostatic tremor( POT) was thus confirmed, and the patient was placed on pharmacotherapy. She started travelling without fear of falling; I was pleasantly surprised to receive from the patient a picture postcard mailed from Luxor, Egypt portraying the giant statue of Ramses II.
It is quite fascinating to delve into the story of the discovery of the stethoscope and its subsequent evolution over the years. When Dr. Laennec started practicing medicine in 1804 in Paris, France, the standard practice was for the physician to listen to the lungs and the heart through“ direct auscultation”( by placing the physician’ s ear directly on the bare chest of the patient). The story is that Dr. Laennec was about to examine a young lady with symptoms of heart disease and apparently felt a bit uneasy about“ direct auscultation.” Somehow, he had the inspiration to roll a piece of paper into a tube and listen to her heart sounds by placing one end of the tube to the patient’ s chest and the other end to his ear. Dr. Laennec was also a musician and his experience in making flutes led to the use of a hollow wooden piece in place of the paper roll. He used the term stethoscope from the Greek words stethos( chest) and scope( to view or see). In 1819 he published his findings in a two-volume treatise,“ On Mediate Auscultation, a Treatise on the Diagnosis of Diseases of the Lungs and Heart,” which instantly captivated the interest of the medical community. There has been a steady stream of modifications over the decades leading to the binaural stethoscope and use of headset, chest piece and rubber tubing. 1 The Harvard cardiologist Dr. David Littmann was instrumental in bringing perfection to the stethoscope technology with the use of bell and diaphragm for listening to sounds of high as well as low pitch. The elegant and light weight Littmann stethoscope eventually became the all-time favorite.
Technological revolution propelled the development of electronic stethoscopes with features such as sound amplification, noise cancellation and recording capability. The evolution continues with the use of digital technology and AI affording smart phone applications and data processing. Use of Bluetooth technology has added to the practical utility as it can obviate the need for smart phone interphase. An innovative model has audio filters to optimize detection of cardiac, pulmonary and other body sounds and hands-free listening, in addition to displaying heart rate as well as a 3 lead EKG. The most exciting development is the availability of“ wearable electronic stethoscope” which captures bioacoustics signals from heart and lungs and transmits them for AI based analysis. 2 These devices are a boon for long term monitoring and the practice of telemedicine.
Let me conclude with a quote from Peter Mere Latham( 1789 – 1875), an esteemed British clinician and an auscultation enthusiast( nicknamed“ Heart Latham”). In his book, Lectures on Subjects Connected with Clinical Medicine, a chapter is dedicated to auscultation: General Estimate of the Uses of Auscultation applied to the Heart. He writes:“ What I have laid before you is the alphabet, or at most the spelling-book, without which you will never be able to understand the auscultatory language expressive of diseases of the heart. And until you know it, and know it well, you must go on blundering and guessing as children do, until they have learned to read.”
References:
1
Seah JJ et al. Review on the advancements of stethoscope types in chest auscultation. Diagnostics( Basel). 2023; 13( 9): 1545.
2
Roh KM, Awosika A, Mills RM. Advances in wearable stethoscope technology: Opportunities for early detection and prevention of cardiovascular diseases.
Cureus 2024 doi10.7759 / cureus. 75446.
Dr. Iyer practices at the Neurodiagnostic Center of Louisville and is a retired professor of neurology at the University of Louisville School of Medicine.
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