The Arab physicians during the 9th century A.D. did not know blood pressure as we understand it today, as reflected by their books such as Al Razi’s encyclopedic medical book Al-Hawi fit tib1, but they probably intuitively assessed the force of blood flow subjectively by pulse palpation. They knew the pulse very well, because it was known by the Greeks, Egyptians and the Chinese before them. The Egyptians knew that blood flowed through the body. The ancients did not know the concept of blood pressure as we know it today but the character and the force of the pulse could have given them a feeling of the pressure and the blood flow. Not so ancient, but relatively recently, William Osler at 1892 mentioned in his discussion on chronic Bright disease “increased pulse tension” rather than hypertension2.
    The Chinese were probably the first to recognize the pulse around 2500 BC (Fig. 1). The Yellow Emperor’s Classic of Internal Medicine, Nei Ching, contain references to the pulse3. The Chinese gained so much experience by feeling the arterial pulses that they were able to associate the bad effect of salt on the arteries. The Nei Ching noted “If too much salt is used for food, the pulse hardens”4.

The Egyptians

“Ancient Egyptians knew the origin of the pulse and the pumping function of the heart”5. The Egyptians were the first to suggest that “air and blood enters the heart, and the heart distributes them to the rest of the body”6.
    The pulse was mentioned by the Egyptians in the Edwin Smith Papyrus, 1600 BC (Fig.2), The Therapeutic Papyrus Of Thebes, 1552 BC, and Ebers Papyrus, 1550 BC7.
    The Edwin Smith papyrus has the following observations on the pulse and its relationship to the heart beat:

... examining is like one counting a certain quantity with a bushel, or counting something with the fingers ... like measuring the ailment of a man in order to know the action of the heart. There are canals in it [the heart] to every member. Now if the priests of Sekhmet or any physician put his hands or his fingers upon the head, upon the two hands, ... upon the two feet, he measures to the heart ... because its pulsation is in every member ... Measure ... his heart in order to recognize the indications which have arisen therein; meaning ... in order to know what is befalling therein8.

 

Fig. 2: Counting the pulse as described hieroglyphic characters in Smith papyrus. Symbol on the right represent seeds being emptied from container8.

The Therapeutic Papyrus of Thebes 1552 BC stated:

“If the physician places his finger on the head, neck, arms, hand, feet or body, everywhere he will find the heart, for the heart leads to every member and speaks in the vessels of every member”9

The description in Ebers Papyrus is as follows:

“To know the movements of the heart and to know the heart ... From the heart arise the vessels which go to the whole body ... if the physician lay his finger on the head, on the neck, on the hand, on the epigastrium, on the arm or the leg, everywhere the motion of the heart touches him, coursing through the vessels to all the members ... When the heart is diseased its work is imperfectly performed; the vessels proceeding from the heart become inactive, so that you cannot feel them ...If the heart trembles, has little power and sinks, the disease is advancing”8.

“If you examine a man for illness in his cardia, and if he suffers from pain in his arms, in his breast, and in one side of his cardia, it is death threatening him10.

The Greeks

The Greeks thought that the pulse was due to air which filled the arteries. Erasistratus advanced the belief that the ‘pneuma’ in the arteries was derived from respiration. But Galen thought that the arteries are solid body and the pulse was that “peculiar action initiated of the heart”. He described the main characteristics of the pulse: speed, size, strength, quality and tension8.

The Arabs
 

  Arab medicine reached its highest level between the 8th and the 13th century when Baghdad was the scientific capital of the world. The Arab and Muslim physicians based much of their theoretical information and clinical practice in relation to the heart and the pulse mainly on the Greek medicine.
Arab physicians took full advantage of their position in history, acquiring knowledge from Chinese, Greek and Indian writings, free from the influence of the magic of the dark ages. They translated the available knowledge of other civilizations before them and preserved it. They added their own observations and wisdom and passed their contribution to the world civilization that followed.

  The first physician who wrote about the pulse in Arabic was Abu Zakariya Yuhanna Ibn Masawayh (777-857) a Christian, known in Latin literature as Mesue Senior. He learned anatomy by dissecting animals. He was a physician to the caliph in Baghdad and a hospital director. The Galenic pulse was modified and greatly improved by Al Razi (Rahazes 865-932)7.

   Ibn Sina (Avicenna 980-1037A.D.) wrote in his book The Canon, a detailed description of the pulse, characteristics, and variation in health and disease. He was considered the successor of Galen, and he kept that position for 500 years. He devoted a large portion of his work to the study of the pulse. He described more than 50 identifiable pulses. Avicenna wrote in The Canon:

The pulse is a movement in the heart and arteries . . . which takes the form of alternate expansion and contraction7.

He also referred to the pulse in his Arabic poetry: “Differences in pulsation mean illness and causation”. The Arabs referred to Galen as “THE PHYSICIAN”. His teaching was highly

Fig 3a: Ibn Alnafis manuscript first page.

Fig 3b: Ibn Alnafis manuscript.

wrong. There were no visible nor invisible holes in the interventricular septum” 11.
    Ibn Al Nafis said that blood from right heart cavity goes to the lung through the Arterialized Vein (Pulmonary Artery). In the lungs the blood divides into two: thin blood filters through pores of the arterialized vein (pulmonary Artery) and thick blood remains in the lung for its nutrition. The thin blood mixes with the air that comes from the trachea and enters the vein-like artery (pulmonary veins) through its wall. The thin blood mixed with air, reach the left heart cavity, the center where vital spirit form. The spirit moves from the left heart cavity to the aorta and the rest of the arteries to the tissues.
    So Ibn Al-Nafis suggested that blood moves from Arteries to Veins across the wall inside the lungs, but his student, Ibn Al Quff, explained later in his book kitab al-omda fi sina’at altib, i.e., basic works concerning the art of surgery12, and proposed the existence of capillaries. This was not actually confirmed until the era of the microscope when Malphighi saw the capillaries in 1661.
  Ibn Al Nafis also said that the heart muscles

Fig 4: Galen’ physiology.

receive nourishment from the arteries [coronary arteries] that pass through it, not directly from the blood in the heart cavity as Galen claimed. He described his finding in his book Sharh Al Tashrih four hundred years before Harvey published “De Motu Cordis”. Ibn Al Nafis’ book was available for Harvey to see when he went to Italy to study in Padua University.
    Ibn Al Nafis wrote more than twenty books, including Alshamil, a multivolume encyclopedia of medicine. He also wrote books on pediatrics and ophthalmology. He devoted one paper to the pulses.
     Western writers admit that: ”The Arabic teaching on the pulse became standard reference works, many of which have survived into the present day”7.
     Until the death of Ibn Al Nafis in 1288, there was no mention of blood pressure or hypertension in the medical literature. A few centuries later, physiologists made the discovery.
 

The road to sphygmomanometer

Although physiologists who studied animals knew about the phenomenon of blood pressure in the 1700s, it was many years before physicians figured out how to measure it in humans.

Stephen Hales (1677-1761) a British physiologist was the first to be credited with direct blood pressure measurement in 1733. Hales studied the role of air and water in the maintenance of both plant and animal life. He also studied theology to become a priest and received Bachelor of Divinity from Oxford. He was a practicing clergyman and devoted some of his time for scientific research. He became the father of sphygmomanometry for determining the blood pressure of animals. He bled to death sheeps, dogs and a horse in his experiments. He was the first to measure arterial pressure8. After casting a white mare to the ground and tying her to a stable door, he laid open the carotid artery. Into it he inserted a brass pipe which in turn was linked to a glass tube13. He measured a column of blood eight feet three inches tall above the level of the horse’s left ventricle (Fig. 5). The horse experiment was historic for the history of blood pressure. He kept bleeding the helpless horse and watching the effect on the pressure until the horse died. He then performed a post-mortem examination on it7.

 

Fig. 5: Hales BP measurement – Repainted for Heart views8.

Carl Friedrich Wilhelm Ludwig (1816-1895): It was not until 1847 that human blood pressure was recorded by Ludwig, a German physician. The Ludwig’s kymograph method used catheters inserted directly into the artery. He made the first graphical recording of BP using a U-shaped mercury manometer connected to a kymograph (wave writer). He was also a physiologist and devised the kymograph as a means of obtaining a written record of the variations in the pressure of the blood.
 

Karl Vierordt (1818-1884), a German physiologist made an instrument to measure the pulse pressure and called it Sphygmograph (Greek Spymo, pulse). In 1855, he found that with enough pressure, the arterial pulse could be obliterated. A cup was connected to a sensitive lever, which was placed on the pulsating radial artery and weights were placed on the cup until the pulse was obliterated. The arterial pulse lifted the cup in a rhythmic fashion and a pin connected to another lever produced a graphic record. It was a non-invasive method but it only measured the pulse amplitude7.

Etienne Jules Marey (1830-1904): A French physician who after taking his medical degree from Paris did not like the practice of medicine. He became a pioneer in movie picture and is credited as the father of cinematography. He was also interested in the pulse and developed Vierordt idea further in 1860. He invented the direct sphygmograph without arterial cannulation to be fixed on the forearm with a plate rest on the radial artery. Marey’s sphygmograph, was one of the most famous scientific instrument of the 19th century7. Marey’s sphygmograph was portable and could easily be used by clinicians. The pulse could be recorded on paper away from the instrument (Fig. 6) It could accurately measure the pulse rate, but was very unreliable in determining the blood pressure.

Fig 6: Single pulse curve from a spygmograph.

Yet his design was the first that could be used clinically with a small degree of success.

Samuel Siegfried Karl Ritter von Basch (1837-1904): Was a physician in Vienna who invented in 1881 another sphygmomanometer. His device consisted of a water-filled bag connected to a manometer. The manometer was used to determine the pressure required to obliterate the arterial pulse. His method was based on the principle of occluding the artery by external pressure and measuring that pressure when the pulse disappeared. His device was small, portable, and easy to use at the bedside7.
During the 19th century many modifications of the sphygmomanometer was produced in Europe but it is not necessary to mention all of them in this article.

Richard Bright (1789 – 1858): The story of hypertension, however, began with Richard Bright. His name appears in old medical textbooks as “Bright disease”, a vague and obsolete term for disease of the kidneys, acute or chronic.
   Richard Bright enrolled at the University of Edinburgh, where he at first studied moral philosophy, political economy, nature philosophy and mathematics in 1808. The following year, he changed to medicine. Pathology and post-mortem examinations became his great interests, besides clinical work. In 1836 Bright published 100 autopsies with chronic kidney disease correlating clinical and pathological finding. He noted hypertrophy of the heart and blamed it on increased peripheral resistance14.
 

Fig 7a: Mahomed’s sphygmograph.

old sprains, aches and pains in the joints etc. So successful was his treatment that hospitals referred patients to him. King George IV honored him with the appointment of “Shampooing Surgeon to His Majesty George IV.” He also became Shampooing Surgeon for William IV.
     His grand son Frederick Akbar Mahomed at age 18 went to study medicine at the Royal Sussex County Hospital. At age 20, he entered Guys Hospital in London to study medicine and became interested in Marey’s sphymograph. He modified the sphymograph while still student15. In 1870 Akbar won the pupils’ Physical Society Prize for developing the sphygmograph two years before graduation in 1872. When he started medical residency in the hospital he became interested in Bright’s disease. He used his instrument clinically to measure pressure in patients with scarlet fever thereby becoming the first person to discover that raised blood pressure was an early sign of inflammation of the kidneys. While a second year resident he published his observation with the sphygmograph in 1874:

that the pulse of acute Blight’s disease closely resembles that which had previously been described and illustrated by the sphygmograph as occurring in chronic Blight’s disease, or more strictly speaking, with cirrhosis of the kidney. Both conditions were accompanied by a pulse of high tension . . . and especially was distinguished by a prolongation or undue sustension of the tidal wave15.

He had already, at this stage of his training, recognized that high BP existed as a separate event, and was the precursor and cause of albuminuria, rather than the reverse as it was believed then:
 

. . . previous to the commencement of kidney change, or to the appearance of albumien in the urine, the first condition observable is high tension in the arterial system15.

In 1879 he wrote: I feel sure, that the clinical symptoms and the pathological changes resulting from high arterial pressure are frequently seen in cases in which very slight, if any disease is discoverable in the kidney15.

Mahomed’s sphymograph was clumsy except in his own hands (Fig. 7), He was able to diagnose several arterial aneurysms from its tracing. It actually measured the tension of the pulse rather than the BP itself8.
   After qualification in Guys hospital in 1872, Mahomed obtained his MD degree from Brussels (1874) and MB from Cambridge (1881), and in 1880 he was elected Fellow of the Royal College of Physicians15.
  Louis J. Acierno the author of The History of Cardiology stated:
 

Fig 7b: Mahomed’s sphygmograph illustrated sketch.

Mahomed should be credited with being the first to realize that acute nephritis is associated with an increase in arterial pressure. This was reported in his paper: The etiology of Bright’s disease and the prealbuminuric stage, published in 1874, only two years after qualifying as a medical practitioner. This was followed by a series of papers dealing with “arteriocapillary fibrosis” and the various clinical manifestations of Bright’s disease. He combined for the first time estimates of arterial tension, measured in troy ounces, with clinical and pathological observations8.

 

Fig 8a: Riva-Rocci sphygmomanometer..

   In his paper on the sphygmographic evidence of “arteriocapillary fibrosis” he commented on how he observed people with no overt evidence of kidney disease, either in the urine or otherwise, and yet, who manifested “high arterial tension”16.
   Even in his collection of postmortem studies on the kidneys, he describes patients with “red contracted kidneys” with symptoms of heart disease or cerebral hemorrhage who had “signs of high arterial tension with absence of albuminuria”17. Before Mahomed paper, it was assumed that the etiology of high BP was kidney disease. He recognized the existence of high BP with out kidney disease. He stated:
 

My first contention is that high pressure is a constant condition in the circulation of some individuals and that this condition is a symptom of a certain constitution or diathesis . . . These persons appear to pass on through life pretty much as others do and generally do not suffer from their high blood pressures, except in their petty ailments upon which it imprints itself . . . As age advances the enemy gains accession of strength ... the individual has now passed forty years, perhaps fifty years of age, his lungs begin to degenerate, he has a cough in the winter time, but by his pulse you will know him . . . Alternatively, headache, vertigo, epistaxis, a passing paralysis, a more severe apoplectic seizure, and then the final blow . . . Of this, I feel sure, that the clinical symptoms and the pathological changes resulting from high arterial pressure are frequently seen in cases in which very slight, if any disease is discoverable in the kidney. The observations provide strong evidence of Gull and Sutton’s work. It appears to me that these clinical, and their pathological, observations must stand or fall together; that one is the pathological, the other the clinical aspect of the same condition17,18.

  In October 1884, while working in the fever hospital, Mahomed, fell ill with typhoid fever and died in November 1884 at the age of 35. He had such fruitful but short professional career of just 15 years.

Fig 8b: Riva-Rocci sphygmomanometer diagram.

Louis J. Acierno commented on his death: “I wonder what he could have accomplished if he had lived for at least another two or three decades”8.

The mercury sphymomanometer

Scipione Riva-Rocci (1863-1937): An Italian professor, developed the mercury sphygmomanometer in 1896 (Fig. 8). He reported a non-invasive method of obtaining BP that ultimately led to the present technique with mercury sphygmomanometer19. An inflatable cuff was placed over the upper arm to constrict the brachial artery. This cuff was connected to a glass manometer filled with mercury to measure the pressure exerted onto the arm. A column of mercury was used to quantify the pressure required to inflate a rubber cuff. The air was pumped until the pulse disappeared; it was then released until the pulse reappears and the reading was then taken (systolic BP)20.
   Riva-Rocci’s cuff was too narrow, resulting in inaccurate measurements. Von Recklinghausen, a German professor in 1901 recognized this error and widened the cuff from 5 to 13 cm.
   While all the above development on pulse and BP instruments was taking place in Europe during the 19th century, there was little, if any development, taking place in that field, across the ocean in the USA. In 1901, while traveling in Europe, the American neurosurgeon Harvey Cushing (1869-1939) visited Riva-Rocci in Pavia, Italy7. He saw Riva-Rocci’s blood pressure instrument in clinical use21. Cushing, solicited a gift of one of the Riva-Rocci cuffs and brought it back with him to Baltimore, USA, where he began to encourage its use among the house officers at Johns Hopkins Hospital22. He introduced BP recording in anesthesia charts during surgery to check the heart strength. From 1912, Massachusetts General Hospital started BP measurement of all admissions20.
 

Fig. 9: Laennec using his stethoscope, repainted for Heart Views.

   Cushing was not only a famous neurosurgeon but he was also a medical historian and is recognized as the biographer of Sir William Osler. One of his quotations I found in the internet: “I would like to see the day when somebody would be appointed surgeon somewhere, who had no hands, for the operative part is the least part of the work”24.
The above method of determining the BP was cumbersome and not very accurate. The stethoscope was already invented and available by that time but no one discovered its value for BP determination yet.

Necessity is the mother of invention

It was the Inhibition and shyness of a young physician that led to the invention of the stethoscope. The first stethoscope (Fig. 9) was fashioned in 1816 by a young French physician in Paris, Dr. Rene Theophile Hyacinthe Laennec (1781-1826). A young lady with signs and symptoms of heart disease was presented to him. He wanted to listen to the chest to confirm his diagnosis. The standard auscultatory technique for a physician then would be to press his head against the patient’s chest in order to listen to the resonations. He was too inhibited and shy to touch her chest. Rather than cause himself undue embarrassment, he rolled a piece of paper into a tube, and used that rather than touch her chest. To his astonishment, he could hear the heart just as well as if he had put his ear on the chest.
    He also found that the tubercle lesion were not limited to the lungs but could be present in all organs of the body; he did not, however, realize that the condition was infectious. His mother, his uncle and a close friend died with tuberculosis. Unfortunately while studying tuberculosis (Fig. 10), he contracted the disease and died at the early age of forty-five.
 

Fig. 10: Laennec examining a patient with lung disease, probably TB20.

    I never thought that a French man would be so shy to touch a lady. The Arab woman in general is inhibited of being examined by a male physician. When I was a child, a “doctor” from our village came back from a school in India. My father requested him to treat my anemic mother who complained of palpitation. She did not agree to be seen by a male doctor. She stood behind the door and I had to put the stethoscope over her chest for him to listen. He did not know what he was hearing any way, because we found out later, that he was not a doctor. He was a dental technician.

   From reading the history of medicine, I learned that the examination of the female pulse was approached differently than that of a male in many cultures such as the Chinese, the Indian and even the European. In ancient China, the female pulse was palpated across a bamboo curtain. The taboo against any form of physical contact with the female patient brought about the introduction of diagnostic dolls. The patient would mark the site of the disorder on the figurine.

    Diagnostic dolls were also used during Victorian era in England8. Queen Victoria (1819-1901) was noted for her “great aversion” to the stethoscope. Sir James Reid, her attending physician said on remembering her: “the first time I had ever seen the Queen . . . in bed was when she was actually dying”, and it was only after her death that he discovered that she had “ventral hernia, and prolapse of the uterus” - proof that he had never given her a full physical examination20. It is possible that physicians then avoided physical touch of female patients to prevent others from accusing them with indecent behavior. A painter (W. Ward in 1802 after J. Opie) painted a physician taking a young lady’s pulse as seducer20 (Fig. 11).
   For reasons unknown to me, the Hindus palpated the pulse on the right side in men, and on the left side in women8.

Fig 11: Suducer.

The stethoscope joins the sphygmomanometer
 

The marriage between the stethoscope and the sphygmomanometer was performed by a Russian. In 1905, a humble Russian surgeon, Nikolai Sergeyevich Korotkoff (1874-1920), described the sounds heard with a stethoscope placed over the brachial artery below the Riva-Rocci-von Recklinghausen cuff during slow deflation. With the Korotkoff method it became easy for the first time in history to determine both systolic and diastolic BP. This bright Russian surgeon died at the young age of forty six. His discovery was one of the most outstanding events in the history of medicine. It put in the hand of clinicians throughout the world an extremely simple diagnostic approach capable at the same time of being very accurate.
   After 1910, physicians steadily simplified their practice of pulse palpation and accepted auscultation of systolic and diastolic blood pressure.
   Korotkoff’s finding was the reason for the discovery of a disease that must have been present for millennia. The disease is hypertension, one of the leading causes of death in the world. Untreated, it could cause severe damage to the heart, kidneys, the brain and other target organs. I was threatened with it as a high school student, probably due to a faulty sphygmomanometer when I complained of headache. My headache then was caused by school tension rather than hypertension.¨

 

Fig 12: Stethescope anf Sphygmomanometer.

References:

1. Al Razi: Alhawi fit tib. 2000; Dar Alkutob Alalmyyah, Beirut.

2. William Osler: The principle and practice of Medicine, D. Appleton & Com. p.754.

3. Veith, Ilza: The yellow Emperor’s classic of internal medicine. 1949; Univ. of California press.

4. Michael Wood et al: Athe Ancient medicine. 2000; Runestone Press.

5. Rashkind W J: Historical aspects of surgery for congenital heart disease. J. Thorasic. Cardiovas. Surg. 1982; 84:619-625.

6. P. Ghalioungui: Ktoof min tareekh et-tib (Arabic).

7. N. H. Naqvi and Blaufox: Blood Pressure measurement. 1998; The Parthenon Publishing Group.

8. Louis J. Acierno: The History of Cardiology, 1994; The Parthenon Publishing Group.

9. V. Robinsons: The story of medicine, Tudor Publishing co. 1931; p.22

10. Ebers papyrus – J. of Royal. Phys. of London 1984;18(3):182-186.

11. Ibn Al Nafis: Sharh Tashreeh Al Canon. 1988; Egyptian Gen. Auth. For book. (Arabic)

12. Ibn Al Quff: Kitab al-omda fi’at altib (Arabic) printed in Hyderbad, India.

13. Bettmann Otto: A pictorial history of medicine. 1956; Charles C. Thomas Publisher.

14. Bright, R. Tabular view of morbid appearance in 100 cases of hypertension connected with albuminous urine. With observation. 1836; Guy’s hospital. Rep.1, 380.

15. Lewis O. J. of Human Hypertension. 1997; 11: 255-261.

16. Mahomed F.A. 3. On the sphygmographic evidence of arteriocappillary fibrosis. 1877; Trans. Path.soc. 28, 394.

17. Mahomed F.A. On chronic Bright disease, and its essential symptoms. Lancet 1879; I: 46.

18. Mahomed F.A.. Some clinical aspects of chronic Bright disease. 1879; Guy’s Hosp. Rep., 3rd. ser., 24, 363.

19. Riva-Rocci, S. un nuovo sfigmomanometro. Gasetta medical di Torino. 1986; 47: 51 &52.

20. Porter Roy: Greatest Benefit to mankind. 1997; Harper Collins Publishers.

21. Cushing H. On routine determinations of arterial tension in operating room and clinic. Boston Medical and Surgical Journal. 1903; 148:250-2

22. Fulton JF. Harvey Cushing: A Biography. Springfield, IL; Charles C. Thomas publisher. 1946:178-9, 184.

23. Lyones A. S: Medicine an Illustrated History 1912; Abradale Press.

24. Letter to Dr Henry Christian Nov 20, 1911.