Table of Contents
Significant Events 1900-1919:
- 1903: Wright Brothers fly a heavier than air craft
- 1909: Paul Erlich introduces Salvarsan, a synthetic arsenical compound as treatment for syphilis, the first chemical for treatment of infectious disease
- 1913: Bela Schick introduces test for diphtheria immunity
- 1914-1918 - World War I
- 1919: Thomas H. Morgan publishes "Physical Basis of Heredity
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The Stimulating Pincers (Pince Excitatrice) - Floresco N.
In order to stimulate deeply placed internal organs we employed a pincers-like instrument constructed with two insulated copper wires supported on a wooden rod and surrounded by a tightly wound wire coil. Two ends of the wires were connected to the secondary coil of an electric generator. The other two ends served to give the electric discharge and were sometimes soldered to platinum electrodes.
This pincers was then used to stimulate the interior and exterior of deeply placed internal organs.
When we intend to stimulate internal organs the pincers is introduced into a glass tube with a curved tip. With the end protected by the tube, we were able to introduce the pincers without causing either a tear or hemorrhage within the organs, while advancing the pincers into position.
Placing the pincers within the tube permits its introduction via the jugular vein into the heart to study the effect of electrical discharge from the copper wires or platinum electrodes which exit the glass tube, on blood coagulation, and to study the effect of the electric current on the atrium, the atrioventricular orifice, at several points in each chamber and on the nerves which surround the vascular trunks.
The tip of the pincers, introduced via the jugular vein, was directed outward until reaching the liver where the influence of the electric current on the sugar level of blood entering and exiting the liver could be measured.
J Physiol Path General 1905;7:785-786
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Restoration of Life By Direct Stimulation of the Heart
Experiment. Cardiac arrest with ether. Direct Internal Cardiac Excitation.
Rappel a la Vie Par L'Escitation Directe du Coeur
Floresco N. A large dog was anesthetized with ether and fastened to an operating table. The neck was exposed and a mid-line incision 10 cm long was extended to the upper end of the sternum. The left carotid artery was exposed to determine arterial pressure. On the right the jugular vein was exposed and detached from its aponeurosis for 5-6 centimeters.
The specialized stimulating pincers, placed within a glass tube with a small bend at its tip, was introduced via an incision in the vein. The tube was pushed carefully but with some force and entered the auricle and then the ventricle. Pushing the end of the stimulating pincers it exited the end of the tube to give electrical discharges. We attempted to observe, from the outside, whether the pincers had been properly placed into the heart by the motion transmitted to the pincers. A ligature was placed to stop the escape of blood. To prevent blood clotting we placed vaseline on the pincers before introducing the glass tube.
After recording normal pressures we elected to stop circulation and respiration by intoxication with ether.
After 30 minutes of observation we began internal cardiac stimulation and contractions began. These stimuli induced a normal rhythm and the animal returned to life.
Internal stimulation produced a more rapid effect than external stimulation but presented the following difficulty: a strong and prolonged electrical stimulus produced clots which slowed or suppressed the reappearance of the heart beat.
J Physiol Path General 1905;7:797-803
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Instrumental Methods of Examination: The Ink Polygraph
"In the examination of the vast majority of patients, the diagnosis can be made independently of graphic records. It must not be inferred from this that graphic records can be dispensed with, for the power to diagnose the great majority of cases comes through the information obtained by this means. Though it is not necessary for a physician himself to take records, he must be familiar with their interpretation in order that he may appreciate and apply the results."
In this way James MacKenzie introduced the chapter on graphic demonstration of cardiac disease in his book "Diseases of the Heart", 1908 Edition. No ECG was mentioned, though it is illustrated with some 260 graphic displays of radial, jugular, apex, liver and respiration tracings.
105. Method of recording the jugular pulse
Usually the movements of the vein are best recorded with the patient lying down, the shoulders slightly raised, the head comfortably supported by a pillow, and turned slightly to the right in order to relax the right sterno-mastoid muscle. The receiver (E, Figs 13 and 18) is placed over the jugular bulb immediately above the inner end of the right clavicle, with just sufficient pressure to shut off the interior of the receiver from the outer air.
 |  |
| Figure 18 |
| Figure 13 | |
107. Description of the events in a cardiac cycle.
In the diagram (Fig. 43) there is represented a series of movements due to various forces that occur during one cardiac cycle. If a wave is found in the vein, and if its time of occurrence be ascertained by referring to the place it would occupy in this diagram, we can usually find its cause by noting what force is operative at that period. It must be added that while this diagram represents with fair accuracy the chief events in a cardiac revolution, it is not asserted that it is correct in every detail. Authorities are not quite agreed on several small points, but it is sufficient for the purpose I have in view. |  |
| | Figure 43 |
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S. Tawara’s Contribution to the Elucidation of the Conduction System of the Mammalian Heart
By his work carried out at Ludwig Ashoff’s laboratory in Marburg, Sunao Tawara, (1873-1952) established the link between the His bundle and Purkinje fibers by discovering the left and right bundle branches and by identifying the Purkinje fibers as their terminal ramifications. By adding another component, the atrioventricular node, Tawara created the concept of these components as a system, i.e., the conduction system of the heart. He also theorized about the velocity of the excitatory process in the conduction system and the mode of ventricular contraction. Tawara’s anatomic findings and physiological assumptions provided the theoretical basis to Eindhoven for interpreting the electrocardiogram.
Tawara S. Das Reilzeitungssystem des Saugetierherzens.Jena,Veriag von Gustav Fischer 1906 (English edition translated by Suma K. Shimada M. London, Imperial College Press 2000) Suma K. Sunao Tawara: A father of modern cardiology. PACE 2001;24:88-96
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Organized Atrial Tachyarrhythmias in Patients with Atrial Fibrillation
In atrial fibrillation, pacing can only achieve local capture which is not sufficient to terminate the arrhythmia. However, it is unknown if and how frequently patients with atrial fibrillation show intermittent transitions to a more regular atrial tachyarrhythmia such as atypical atrial flutter which may be amenable to antitachycardia pacing. Therefore, in patients with an implanted device capable of storing bipolar atrial electrograms of automatically detected atrial tachyarrhythmias, stored episodes were classified into three types (Fig.):
Type I: Highly organized with discrete deflections of constant morphology, an isoelectric line between signals, and a minimal cycle length
> 200 ms;
Type II: Intermediate organization which neither meets criteria of Type I nor III;
Type III: Disorganized with polymorphic deflections, loss of isoelectric line between signals, and a minimal cycle length < 200 ms. During a monitoring phase of 1 month, all patients with atrial fibrillation as the only atrial tachyarrhythmia documented prior to device implantation also exhibited Type I tachyarrhythmia episodes. In a second study phase, it could be demonstrated that atrial antitachycardia pacing was able to terminate 62% of Type I episodes compared to only 34% of Type II, and no Type III atrial tachyarrhythmia. It was concluded that intermittent transition from disorganized atrial tachyarrhythmia to a higher degree of organization may be found in the majority of patients with atrial fibrillation, and that during these periods of high organization, atrial antitachycardia pacing may be able to terminate a significant proportion of episodes.
Israel CW, Ehrlich JR, Grönefeld G, Klesius A, Lawo T, Lemke B, Hohnloser SH: Prevalence, characteristics, and clinical implications of regular atrial tachyarrhythmias in patients with atrial fibrillation: Insights from a study using a new implantable device. J Am Coll Cardiol 2001; 38:355-363
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On Dynamic Equilibrium In The Heart
G. R. Mines
(section 1) In Fig. 25 is shown the supposed effect of a short pause. After the pause, the liberation of acid is greater, and since the pause was short the general level of acidity has not fallen much. The effective concentration of acid is therefore greater than that due to the preceding of the succeeding excitations. Fig. 26 represents the other case. Here the events supposed to occur after a prolonged pause are represented. The liberation of acid is greatest in the first response of this series and in successive responses it diminishes.
(section 2) With increasing frequency of stimulation, each wave of excitation in the heart muscle is propagated more slowly but lasts a shorter time at any one point in the muscle. The wave of excitation becomes slower and shorter. Similarly the refractory phase (towards strong induction shocks) is shortened.
It follows that by gradual acceleration of the rate of stimulation, the ventricle can be caused to beat at a higher rate than if the rate of stimulation is abruptly raised. Thus with one and the same rate of stimulation there can exist two meta-stable equilibria, in one of which the responses are twice as frequent as in the other. Transition from one state to the other may be brought about by a suitably placed extra systole.
(section 3) If a closed circuit of muscle is provided, of considerably greater length than the wave of excitation, it is possible to start a wave in this circuit which will continue to propagate itself round and round the circuit for an indefinite number of times. The condition is readily upset by an extra systole. It is shown that these observations offer a simple explanation of certain cases of reciprocating rhythm between two chambers of the heart.
(section 4) On circulating excitations in the musculature of a single chamber.
Since the above paper was sent to press I have made further observations on circulating rhythm, which may be briefly noted here. The experiments were carried out at the Plymouth Marine Laboratory on ring preparations cut from the auricles of large rays. In such preparations a single stimulus applied to any point in the ring starts a wave in each direction. The waves meet on the opposite side of the ring and die out. But by the application of several stimuli in succession it is sometimes possible to start a wave in one direction while the tissue on the other side of the point stimulated is still refractory. Such a wave runs round the ring sufficiently slowly for the refractory phase to have passed off in each part of the ring when the wave approaches it. Thus the wave circulates and may continue to do so for fifty revolutions or more. Usually an interpolated extra stimulus stops the wave at once. The preparation may then remain quiescent or it may start beating with a slow spontaneous rhythm. In the latter case the totally different characters of the spontaneous rhythm and the circulating excitation are very striking.
Journal of Physiology 1913;46:349-383
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