Table of Contents
Significant Events 1920-1929:
- 1920: "Babe" Ruth sold by the Boston Red Sox to the New York Yankees for $100,000
- 1922: Banting, Best and MacLeod administer insulin to the first patient
- 1925: Leica 35 mm camera built by Oskar Barnak
- 1928: Alexander Fleming discovers penicillin
- 1929: World wide Great Depression begins
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Mobitz Type II Second-Degree AV Block
In 1924 Mobitz classified second-degree AV block into type I and type II using the electrocardio-gram. The graphic representation of type II block from his publication shows occasional block of one or more P waves with no change in all the PR intervals before and after the non-conducted P waves.The ladder diagrams clearly demonstrate this important constancy of the PR interval. Type II block was associated with a constant sinus rate. Ironically the need for a constant sinus rate for the diagnosis of type II block has been emphasized only recently.
Mobitz W. Uber die unvollstandige storung der errengungsüberleitung zwischen Vorholf und Kammer des menschlichen herzens. Z Ges Exp Med (Berlin) 1924; 41:180-237
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The String Galvanometer Electrocardiograph
Willem Einthoven (1860-1927) had experimented with detection and recording of electricity from the mammalian heart for years, after Waller's recording of a rudimentary electrocardiogram in 1887. Einthoven gradually recognized that far better equipment than was available at the time would be required for successful recording of the electricity developed by cardiac function. The string galvanometer, previously invented and used, among other purposes to amplify electrical signals being transmitted thousands of miles via the transatlantic undersea communications cable, seemed a promising model. He developed a very sensitive galvanometer using an extremely thin and light weight quartz "string" silvered to reflect a beam of light, which was deflected by the passage of a fluctuating current in a powerful magnetic field. This galvanometer was sufficiently sensitive to detect the extremely small electrical events generated by the heart. The recording of the light reflected from the string was on a moving glass photographic plate, later on a roll of photographic paper, both of which were developed to produce the image. The signals were obtained from the two arms and left leg (modern Lead I). To enhance conduction, hands and foot were bathed in saline solution with the tubs wired to the input of the electrocardiograph. Despite disputes about priority, which delayed recognition of Einthoven as inventor, he finally was recognized with the 1924 Nobel Prize in Medicine.
Almost immediately the utility of the electrocardiograph was recognized and classic rhythms were soon obtained and published. Several manufacturers began to produce their commercial versions. The Cambridge Scientific Instrument Co., headed by Horace Darwin (Charles' youngest son), produced a device, shown here in use about a decade and a half after its introduction. The string galvanometer for electrocardiography was superceded by direct writing equipment after the Second World War.
In the electrocardiograph an Einthoven galvanometer is used, which is made on a different principle from the compass galvanometer. Here the movable part is a microscopic thread of quartz called a "string," which is suspended vertically in a strong magnetic field. When a minute current is passed through it, the "string" is deflected, or really bent laterally. As the string is supported at both ends, has a very small mass, and moves only a fraction of a millimeter, it has very little inertia, and can record impulses up to many hundred times per minute. These records are obtained by making the string opaque with a coating of silver, placing it in a beam of light which throws a vertical shadow, magnified by a microscope, onto a metal plate in which there is a horizontal slot. This slot allows only a point of shadow to pass through to a moving photographic plate or film, on which the point of shadow writes in a continuous curve. The apparatus is shown diagrammatically in figure 8.
Illus from Lamson PD. The Heart Rhythms. Williams & Wilkins Company 1921. Pg 21-22
Lamson PD. The Heart Rhythms. Williams & Wilkins Company 1921. pp 20-22.
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The Catheterization of the Right Heart
*For the orginal German text, see below
After the successful cadaver investigation, I undertook the first investigation on a living person, myself. First, I requested that a colleague allow me to use his time and assist in the effort and that he introduce a large bore needle into a vein at my right elbow. Then, as in my cadaver research, a well lubricated ureteral catheter, 4 Charrier in diameter was introduced via the cannula, into the vein. The catheter was easily inserted to a distance of 35 cm. Because my colleague thought that at that point it was too dangerous to continue, we stopped the experiment, but I felt very well afterward. A week later I attempted the same by myself. I made another attempt to perform a venipuncture with a thick needle, but it was excessively difficult to introduce that needle into my own body, so I performed a venesection at my left elbow and introduced the catheter to its complete length of 65 cm. I had measured that length on the body surface as the distance from the left elbow to the heart. The only sensation I had during introduction of the catheter into the venous system was a slight feeling of warmth, not unlike an intravenous injection of calcium chloride. When removing the catheter, as it passed behind the clavicle at the attachment of the sternocleidomastoid muscle, I felt a more intense heat and a light cough as it passed adjacent to the vagus nerve. I checked the position of the catheter on x-ray and observed its movement with a mirror which a nurse held for me, reflecting the fluoroscopy screen.
In the first picture we see the shadow of the catheter into the right axilla. The second picture is the x-ray of the second experiment. The catheter extends from the left arm across the thorax and disappears behind the clavicle and turns downward behind the chest wall to approach the superior vena cava from the left innominate vein, enters the shadow of the superior vena cava and then enters the right atrium. Further advancement of the catheter was limited by its length.
Besides the sensations which I described, I paid special attention to irritation of the cardiac conduction system and could not detect any. In our institution there is a distance between the operating room and the x-ray section which I reached without discomfort, by climbing several steps, while the catheter lay in my heart.
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Figure 1: The catheter is in the right cephalic vein and introduced to the top of the axilla.
Abb. I. Der Katheter ist in der rechten Vena cephalica bis zur Höhe der Achselhötrle eingeführt. | | Figure 2: The catheter reaches from the left celphalic vein to the right atrium.
Abb. 2. Der Katheter reicht von der linken Vena cephalica herabkommend bis in die rechte Vorkammer. |
Die Sondierung Des Rechten Herzens *
Nachdem die Versuche an der Leiche geglückt waren, unternahm ich die ersten Versuche am lebenden Menschen im Selbstversuch. Zunächst ließ ich mir in einem Vorversuch von einem Kollegen, der sich mir für diesen Zweck liebenswürdigerweise zur Verfügung stellte, die rechte Ellenbogenvene mit einer dicken Nadel punktieren. Ich führte dann, wie bei den Versuchen an der Leiche, einen gut geölten. Ureterenkatheter von 4 Charrières Dicke durch die Kanüle in die Vene ein. Der Katheter ließ sich spielend leicht 35 cm hoch einführen. Da dem Kollegen ein Weitergehen zu gefahrvoll er- schien, brachen wir den Versuch ab, bei dem ich mich vollständig wohlfühlte. Nach einer Woche unternahm ich allein einen weiteren Versuch. Ich machte in örtlicher Betäubung, da sich eine Venenpunktion mit dicker Nadel am eigenen Körper technisch zu schwierig gestaltet, eine Venaesectio in meiner linken Ellenbeuge und führte den Katheter widerstandslos in seiner ganzen Länge, 65 cm, ein. Diese Strecke erschien mir nach einer Messung auf der Körperoberfläche dem Wege von der linken Ellenbeuge bis zum Herzen zu entsprechen. Beim Einführen des Katheters hatte ich lediglich während des Gleitens an der Venenwand ein Gefühl leichter Wärme, ähnlich, wie wir es bei intravenösen Einspritzungen von Calciumchlorid empfinden. Bei ruckweiser Bewegung stauchte sich der Katheter an der oberen und hinteren Wand der Schlüsselbeinvene, ich spürte eine besonders intensive Wärme hinter dem Schlüsselbein unter dem Ansatz des Kopfwenders; gleichzeitig, wohl durch Reizung von Vagusästen, einen leichten Hustenreiz. Die Lag des Katheters überprüfte ich im Röntgenbild, und zwar beobachtete ich das Vorschieben des Katheters selbst in einem von einer Schwester vor den Durchleuchtungsschirm gehaltenen Spiegel.
Im ersten Bilde sehen wir den Schatten des kontrastgebenden Katheters bis in die rechte. Achselhöhle hinauflaufen (Fernaufnahme). Im zweiten Bilde sehen wir das Lichtbild des zweiten Versuches: Der Katheter liegt, vom linken Arme gerade heraufkommend, auf der Brustwand, er verschwindet hinter dem Schlüsselbein und macht in der Höhe der Einmündungsstelle der linken Drosselvene einen Bogen nach unten, legt sich an den rechten Rand des Gefäßschattens und läßt sich dort - teilweise gedeckt vom Randschatten der Wirbelsäule - bis in die rechte Vorkammer verfolgen. Zu einer weiteren Sondierung reichte die Länge des Katheters nicht aus.
Irgendwelche anderen als die oben beschriebenen Empfindungen, ich achtete besonders auf Reizerscheinungen von seiten des Reizleitungssystems des Herzens, konnte ich nicht feststellen. Auch den in unserer Anstalt ziemlich weiten Weg vom Operationssaal zur Röntgenabteilung, auf dem ich auch Treppen steigen mußte, mit im Herzen Liegender Sonde zu Fuß zurückzulegen, war nicht mit Unannehmilichkeiten verknüpft.
Forssmann. W. Die Sondierung Des Rechten Herzens. Klinische Wochenschrift 1929;8 (45):2085-2087.
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Reciprocating Tachycardia
Original publication of a case of permanent reciprocating tachycardia. This arrhythmia was initially reported, and its reciprocating mechanism first hypothesized and fully described by the French cardiologist Leon Gallavardin (Gallavardin L.,Gravier l. Deux cas de tachycardies en salves chez de jeunes sujests. Arch Mal Coeur 1921; 14:71) It took a little less than half a century to have the hypothesis confirmed by programmed stimulation. The upper panel displays the surface and oesophageal tracings with the characteristic caudo-cranial atrial activation and a ’P-R interval shorter than the R-P’. the lower panels display the results of programmed atrial stimulation and the corresponding ladder diagrams.
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Complete Heart Block
The pulsations of the auricles are also conducted along the arteries, and not infrequently appear upon radial tracings. The mode of transmission to so distant a point is not clearly understood, but it is probable that the base of the aorta acts in much the same way as does an œsophageal sound, such as is used for recording the movements of the left auricle, and that the contractions of the auricular part of the heart which is wrapped around the aorta produce changes in systemic arterial pressure which are transmitted to a distance. Lewis, T. The Mechanism and Graphic Registration of the Heart Beat. Paul B. Hoeber, Publisher. New York, 1920 pp. 178-179.
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