[心电图]的学习.ECG

library contents | ECG axis | ECG history | ECGs by Example An electrocardiogram (ECG / EKG) is an electrical recording of the heart and is used in the investigation of heart disease. This library is a collection of realistic looking recordings which will help improve your ECG skills. Information about the library and the techniques used to reproduce the recordings is available. There are also details of our book ECGs by Example. Contents The normal electrocardiogram. ischaemic heart disease Acute inferior myocardial infarction Acute anterior myocardial infarction Acute posterior myocardial infarction Old inferior myocardial infarction Acute myocardial infarction in the presence of LBBB hypertrophy patterns Left ventricular and left atrial hypertrophy - aortic stenosis Mitral Stenosis Right atrial hypertrophy Left ventricular hypertrophy in the presence of left anterior hemiblock atrioventricular (AV) block First degree AV block 2 to 1 Atrioventricular block Complete Heart Block Complete heart block and atrial fibrillation bundle branch block Right Bundle Branch Block Left anterior hemiblock Left bundle branch block 'Trifascicular' block supraventricular rhythms Sinus bradycardia Sinus tachycardia Atrial Bigeminy Atrial Premature Beat Atrial fibrillation with rapid ventricular response Atrial fibrillation with pre-existing LBBB Atrial Flutter Atrial flutter with 2:1 AV conduction Wolff-Parkinson-White syndrome with atrial fibrillation (20k) ventricular rhythms Ventricular premature beats Ventricular bigeminy Idioventricular escape rhythm in Complete Heart Block Ventricular tachycardia with clear AV dissociation Ventricular tachycardia with subtle AV dissociation (20k) Torsade de pointes ventricular tachycardia Polymorphic Ventricular Tachycardia with an ICD Ventricular Fibrillation pacemakers Ventricular pacemaker Dual Chamber Pacemaker with an ICD Wolff Parkinson White syndrome WPW syndrome - left lateral pathway WPW syndrome - anteroseptal pathway Wolff-Parkinson-White syndrome with atrial fibrillation (20k) Wolff-Parkinson-White syndrome with atrial fibrillation (another example) miscellaneous Implantable Cardioverter Defibrillator Electrical Alternans - pericardial effusion Long QT interval Romano-Ward Syndrome Lown-Ganong-Levine Syndrome Acute pulmonary embolus Hyperkalaemia Hypokalaemia Piggy-back heart transplant Digitalis effect other The electrical axis at a glance. A brief history of electrocardiography A page of comments and corrections for our book 'ECGs by Example'. created: 10th July 1996 updated: 2nd June 2009 authors: Dean Jenkins, Consultant Physician, UK Stephen Gerred, Consultant Physician, Auckland, New Zealand comments always welcome © Copyright 1995-2009. Dean Jenkins and Stephen Gerred. The ECGs and associated images on these webpages may be used for any non-commercial purpose as long as their source is acknowledged. Served by Tremethick web design The electrical axis at a glance ... 2 glances actually. Using leads I and aVF the axis can be calculated to within one of the four quadrants at a glance. If the axis is in the "left" quadrant take your second glance at lead II. both I and aVF -ve = axis in the Northwest Territory lead I -ve and aVF +ve = right axis deviation both I and aVF +ve = normal axis lead I +ve and aVF -ve lead II +ve = normal axis lead II -ve = left axis deviation causes of a Northwest axis (no man's land) emphysema hyperkalaemia lead transposition artificial cardiac pacing ventricular tachycardia causes of right axis deviation normal finding in children and tall thin adults right ventricular hypertrophy chronic lung disease even without pulmonary hypertension anterolateral myocardial infarction left posterior hemiblock pulmonary embolus Wolff-Parkinson-White syndrome - left sided accessory pathway atrial septal defect ventricular septal defect causes of left axis deviation left anterior hemiblock Q waves of inferior myocardial infarction artificial cardiac pacing emphysema hyperkalaemia Wolff-Parkinson-White syndrome - right sided accessory pathway tricuspid atresia ostium primum ASD injection of contrast into left coronary artery note: left ventricular hypertrophy is not a cause left axis deviation library contents | ECG axis | ECG history | ECGs by Example A (not so) brief history of electrocardiography. Find out how electrocuting chickens (1775), getting laboratory assistants to put their hands in buckets of saline (1887), taking the ECG of a horses and then observing their open heart surgey (1912), induction of indiscriminate angina attacks (1931), and hypothermic dogs (1953) have helped to improve our understanding of the ECG as a clinical tool. And why is the ECG labelled PQRST (1895)? 17th and 18th Centuries The harnessing of electricity, observations of its effects on animal tissues and the discovery of 'animal electricity'. 1600 William Gilbert William Gilbert, Physician to Queen Elizabeth I, President of the College of Physicians (before its Royal Charter), and creator of the 'magnetic philosophy' introduces the term 'electrica' for objects (insulators) that hold static electricity. He derived the word from the Greek for amber (electra). It was known from ancient times that amber when rubbed could lift light materials. Gilbert added other examples such as sulphur and was describing what would later be known as 'static electricity' to distinguish it from the more noble magnetic force which he saw as part of a philosophy to destroy forever the prevailing Aristotlean view of matter. Gilbert W. De Magnete, magneticisique corporibus, et de magno magnete tellure. [On the Magnet, Magnetic Bodies, and the Great Magnet of the Earth] 1600 1646 Sir Thomas Browne, Physician, whilst writing to dispel popular ignorance in many matters, is the first to use the word 'electricity'. Browne calls the attractive force "Electricity, that is, a power to attract strawes or light bodies, and convert the needle freely placed". (He is also the first to use the word 'computer' - referring to people who compute calendars.) Browne, Sir Thomas. Pseudodoxia Epidemica: Or, enquiries Into Very Many Received Tenents, and Commonly Presumed Truths. 1646: Bk II, Ch. 1. London 1660 Otto Von Guericke builds the first static electricity generator. 1662 Descarte's reflex ©BIU The work of Rene Descartes, French Philosopher, is published (after his death) and explains human movement in terms of the complex mechanical interaction of threads, pores, passages and 'animal spirits'. He had worked on his ideas in the 1630s but had abandoned publication because of the persecution of other radical thinkers such as Galileo. William Harvey had developed similar ideas but they were never published. Descartes R. De Homine (Treatise of Man); 1662: Moyardum & leffen, Leiden. 1664 Jan Swammerdam, a Dutchman, disproves Descartes' mechanistic theory of animal motion by removing the heart of a living frog and showing that it was still able to swim. On removing the brain all movement stopped (which would be in keeping with Descarte's theory) but then, when the frog was dissected and a severed nerve end stimulated with a scalpel the muscles twitched. This proved that movement of a muscle could occur without any connection to the brain and therefore the transmission of 'animal spirits' was not necessary. Swammerdam's ideas were not widely known and his work was not published until after his death. However, he wrote many letters and his friend, Nicolaus Steno, did attack the Cartesian ideas in a lecture in Paris in 1665. Boerhaave published Swammerdam's 'Book of Nature' in the 1730s which was translated into English in 1758. 1668 electrical stimulation? ©BIU Swammerdam refines his experiments on muscle contraction and nerve conduction and demonstrated some to notable figures such as the Grand-Duke Cosimo of Tuscany who was visiting Swammerdam's father's house on the Oude Schans in Amsterdam. One experiment suspended the muscle on a brass hook inside a glass tube with a water droplet to detect movement and 'irritated' the nerve with a silver wire. This produced movement of the muscle and it may have been due to the induction of a small electrical charge - although Swammerdam would have been unaware of this. In the diagram opposite - a) glass tube, b) muscle, c) sliver wire, d) brass wire, e) drop of water, f) investigator's hand. 1729 Stephen Gray, English scientist, distinguishes between conductors and insulators of electricity. He demonstrates the transfer of static electrical charge to a cork ball across 150 metres of wet hemp thread. Later he found that the transfer could be achieved over greater distances by using brass wire. 1745 Leyden Jar Dutch physicist Pieter van Musschenbroek discovers that a partly filled jar with a nail projecting from a cork in its neck can store an electrical charge. The jar is named the 'Leyden Jar' after the place of its discovery. Ewald Georg von Kliest of Pomerania invented the same device independently. Using a Leyden jar in 1746, Jean-Antoine Nollet, French physicist and tutor to the Royal family of France sends an electrical current through 180 Royal Guards during a demonstration to King Louis XV. 1769 Edward Bancroft, an American Scientist, suggests that the 'shock' from the Torpedo Fish is electrical rather than mechanical in nature. He showed that the properties of the shock were similar to those from a Leyden jar in that it could be conducted or insulated with appropriate materials. The Torpedo fish and other species were widely known to deliver shocks and were often used in this way for therapeutic reasons. However, electrical theory at the time dictated that electricity would always flow through conductors and diffuse away from areas of high charge to low charge. Since living tissues were known to be conductors it was impossible to imagine how an imbalance of charge could exist within an animal and therefore animals could not use electricity for nerve conduction - or to deliver shocks. Furthermore, 'water and electricity do not mix' so the idea of an 'electric fish' was generally not accepted. Bancroft, E. An essay on the natural history of Guiana, London:T. Becket and P. A. de Hondt, 1769. 1773 John Walsh John Walsh, fellow of the Royal Society and Member of Parliament, obtains a visible spark from an electric eelElectrophorus electricus. The eel was out of water as it was not possible to produce the spark otherwise. He used thin strips of tin foil and demonstrated his technique to many colleagues and visitors at his house in London. Unfortunately he never published his eel experiment though he did win the Copley medal in 1774 and 1783 for his work. The observations of Walsh, and Bancroft before him, added to the argument that some form of animal electricity existed. Walsh, J. On the electric property of torpedo: in a letter to Ben. Franklin. Phil. Trans. Royal Soc. 1773;63:478-489 1774 The Rev. Mr Sowdon and Mr Hawes, apothecary, report on the surprising effects of electricity in a case report of recovery from sudden death published in the annual report of the newly founded Humane Society now the Royal Humane Society. The Society had developed from 'The Institution for Affording immediate relief to persons apparently dead from drowning'. It was "instituted in the year 1774, to protect the industrious from the fatal consequences of unforseen accidents; the young and inexperienced from being sacrificed to their recreations; and the unhappy victims of desponding melancholy and deliberate suicide; from the miserable consequences of self-destruction." A Mr Squires, of Wardour Street, Soho lived opposite the house from which a three year old girl, Catherine Sophia Greenhill had fallen from the first storey window on 16th July 1774. After the attending apothecary had declared that nothing could be done for the child Mr Squires, "with the consent of the parents very humanely tried the effects of electricity. At least twenty minutes had elapsed before he could apply the shock, which he gave to various parts of the body without any apparent success; but at length, upon transmitting a few shocks through the thorax, he perceived a small pulsation: soon after the child began to sigh, and to breathe, though with great difficulty. In about ten minutes she vomited: a kind of stupor, occaisioned by the depression of the cranium, remained for some days, but proper means being used, the child was restored to perfect health and spirits in about a week. "Mr. Squires gave this astonishing case of recovery to the above gentlemen, from no other motive than a desire of promoting the good of mankind; and hopes for the future that no person will be given up for dead, till various means have been used for their recovery." Since it is clear she sustained a head injury the electricity probably stimulated the child out of deep coma rather than providing cardiac defibrillation (see also 1788, Charles Kite). Annual Report 1774: Humane Society, London. pp 31-32 1775 Abildgaard shows that hens can be made lifeless with electrical impulses and he could restore a pulse with electrical shocks across the chest. "With a shock to the head, the animal was rendered lifeless, and arose with a second shock to the chest; however, after the experiment was repeated rather often, the hen was completely stunned, walked with some difficulty, and did not eat for a day and night; then later it was very well and even laid an egg." Abildgaard, Peter Christian. Tentamina electrica in animalibus. Inst Soc Med Havn. 1775; 2:157-61. 1786 Luigi Galvani Italian Anatomist Luigi Galvani notes that a dissected frog's leg twitches when touched with a metal scalpel. He had been studying the effects of electricity on animal tissues that summer. On 20th September 1786 he wrote "I had dissected and prepared a frog in the usual way and while I was attending to something else I laid it on a table on which stood an electrical machine at some distance from its conductor and separated from it by a considerable space. Now when one of the persons present touched accidentally and lightly the inner crural nerves of the frog with the point of a scalpel, all the muscles of the legs seemed to contract again and again as if they were affected by powerful cramps." He later showed that direct contact with the electrical generator or the ground through an electrical conductor would lead to a muscle contraction. Galvani also used brass hooks that attached to the frog's spinal cord and were suspended from an iron railing in a part of his garden. He noticed that the frogs' legs twitched during lightening storms and also when the weather was fine. He interperated these results in terms of "animal electricity" or the preservation in the animal of "nerveo-electrical fluid" similar to that of an electric eel. He later also showed that electrical stimulation of a frog's heart leads to cardiac muscular contraction. Galvani. De viribus Electritatis in motu musculari Commentarius. 1791 Galvani's name is given to the 'galvanometer' which is an instrument for measuring (and recording) electricity - this is essentially what an ECG is; a sensitive galvanometer. 1788 Charles Kite wins the Silver Medal of the Humane Society (awarded at the first Prize Medal ceremony of the Society co-judged with the Medical Society of London) with an essay on the use of electricity in the diagnosis and resuscitation of persons apparently dead. This essay is often cited as the first record of cardiac defibrillation but the use of electricity suggested by Mr Kite is much different. For example, on describing a case of drowning from 1785 where resuscitation had been attempted with artificial respiration, warmth, tobacco, "volatiles thrown into the stomach, frictions, and various lesser stimuli" for nearly an hour, he then recalls the use of electricity. "Electricity was then applied, and shocks sent through in every possible direction; the muscles through which the fluid [electricity] passed were thrown into strong contractions." He concluded that electricity was a valuable tool that could determine whether or not a person, apparently dead, could be successfully resuscitated. Annual Report 1788: Humane Society, London. pp 225-244. Kite C. An Essay on the Recovery of the Apparently Dead. 1788: C. Dilly, London. 1792 Alessandro Volta Alessandro Volta, Italian Scientist and inventor, attempts to disprove Galvani's theory of "animal electricity'" by showing that the electrical current is generated by the combination of two dissimilar metals. His assertion was that the electrical current came from the metals and not the animal tissues. (We now know that both Galvani and Volta were right.) To prove his theory he develops the voltaic pile in 1800 (a column of alternating metal discs - zinc with copper or silver - separated by paperboard soaked in saline) which can deliver a substantial and steady current of electricity. Enthusiasm in the use of electricity leads to further attempts at reanimation of the dead with experiments on recently hanged criminals. Giovani Aldini (the nephew of Galvani) conducts an experiment at the Royal College of Surgeons in London in 1803. The executed criminal had lain in a temperature of 30 F for one hour and was transported to the College. "On applying the conductors to the ear and to the rectum, such violent muscular contractions were executed, as almost to give the appearance of the reanimation". Aldini, J. Essai: Th�orique et exp�rimental sur le Galvanisme, Paris (1804), Giovani Aldini. General Views on the Application of Galvanism to Medical Purposes Principally in cases of suspended Animation (London: J. Callow, Princes Street and Burgess and Hill, Great Windmill Street, 1819). Mary Shelly's Frankenstein was published in 1818. Louis Figuier, Les merveilles de la Science (Paris, 1867), p.653 1800 to 1895 The design of sensitive instruments that could detect the small electrical currents in the heart. 1819 While demonstrating to students the heating of a platinum wire with electricity from a voltaic pile at the University of Copenhagen, Danish physicist Hans Christian Oersted notices that a nearby magnetized compass needle moves each time the electrical current is turned on. He discovers electromagnetism which is given a theoretical basis (with remarkable speed) by Andr� Marie Amp�re. 1820 Johann (Johan) Schweigger of Nuremberg increases the movement of magnetized needles in electromagnetic fields. He found that by wrapping the electric wire into a coil of 100 turns the effect on the needle was multiplied. He proposed that a magnetic field revolved around a wire carrying a current which was later proven by Michael Faraday. Schweigger had invented the first galvanometer and announced his discovery at the University of Halle on 16th September 1820. 1825 Leopoldo Nobili, Professor of Physics at Florence, develops an 'astatic galvanometer'. Using two identical magnetic needles of opposite polarity, either fixed together with a figure of eight arrangment of wire loops (in earlier versions), or one moveable needle with a wire loop and one with a scale (in later versions), the effects of the earth's magnetic field could be compensated for. In 1827, using this instrument, he managed to detect the flow of current in the body of a frog from muscles to spinal cord. He detected the electricity running along saline moistened cotton thread joining the dissected frog's legs in one jar to its body in another jar. Nobili was working to support the theory of animal electricity and this conduction, transmitted without wires, he felt demonstrated animal electricity. 1838 Carlo Matteucci Carlo Matteucci, Professor of Physics at the University of Pisa, and student of Nobili, shows that an electric current accompanies each heart