Basics: Difference between revisions

193 bytes removed ,  6 May 2007
no edit summary
mNo edit summary
No edit summary
Line 12: Line 12:


Click on the ECG to see an enlargement.
Click on the ECG to see an enlargement.
Where do we look at watching an ECG?
Where do we look when watching an ECG?
* top left are the patient's information, name, sex and date of birth
* top left are the patient's information, name, sex and date of birth
* at the right of that are below each other the [[heart frequency]], the [[Conduction time intervals (PQ,QRS,QT)|conduction time intervals]] (PQ,QRS,QT/QTc), and the [[cardiac axis]] (P-top axis, QRS axis and T-top axis)
* at the right of that are below each other the [[heart frequency]], the [[Conduction time intervals (PQ,QRS,QT)|conduction time intervals]] (PQ,QRS,QT/QTc), and the [[cardiac axis]] (P-top axis, QRS axis and T-top axis)
* farther to the right is the interpretation of the ECG written (this often misses in a 'fresh' ECG, but later the interpretation of the cardiologist or computer will be added)
* further to the right is the interpretation of the ECG written (this often misses in a 'fresh' ECG, but later the interpretation of the cardiologist or computer will be added)
* down left is the 'paper speed' (25mm/s on the horizontal ax), the sensitivity (10mm/mV) and the filter's frequency (40Hz, filters noise from eg. lights)
* down left is the 'paper speed' (25mm/s on the horizontal ax), the sensitivity (10mm/mV) and the filter's frequency (40Hz, filters noise from eg. lights)
* finally there is a calibration on the ECG, on the beginning of every lead is a vertical block that shows how high 1mV is. So the height and depth of these signals are a measurement for the voltage. If this is not the set 10mm, there is something wrong with the machine.
* finally there is a calibration on the ECG, on the beginning of every lead is a vertical block that shows how high 1mV is. So the height and depth of these signals are a measurement for the voltage. If this is not the set 10mm, there is something wrong with the machine.
* further we have the ECG leads themselves of course, what these are will be discussed below.
* further we have the ECG leads themselves of course, these will be discussed below.


Note the lay-out of the paper is for every machine diffrent, but all of the information above can be found somewhere mostly.
Note that the lay-out is different for every machine, but all of the information above can be found.
{{clr}}
{{clr}}


Line 34: Line 34:
!<flash>file=Single_cardiomyocyte.swf|width=382|height=315|quality=best|align=right||</flash>
!<flash>file=Single_cardiomyocyte.swf|width=382|height=315|quality=best|align=right||</flash>
|-
|-
| Het filmpje toont het samentrekken van een individuele (konijnen)hartcel. De glazen electrode meet de electrische spanning in de hartcel (volgens de [[w:Patch_clamp|patch-clamp methode]]). Het electrisch signaal wordt in blauw uitgeschreven en toont dus een individuele actiepotentiaal. ''Met dank aan Arie Verkerk en Antoni van Ginneken''.
| This movie shows the contraction of a single (rabbit)heartcell. The glass electrode measures the electrical current in the heartcell(according to the[[w:Patch_clamp|patch-clamp method]]). The electrical signal is written in blue and shows the actionpotential. ''Courtesy of Arie Verkerk and Antoni van Ginneken''.
|-
|-
|}
|}
Line 89: Line 89:
In '''1843''' Emil Du Bois-Reymond, a german physiologist, was the to describe "action potentials" of muscular contraction. He used a highly sensitive galvanometer, which contained more than 5 km of wire. Du Bios Reymond named the different waves: "o" was the stable equilibrium and he was the first to use the p, q, r and s to describe the different waves. ''Du Bois-Reymond, E. Untersuchungen uber thierische Elektricitat. Reimer, Berlin: 1848.''
In '''1843''' Emil Du Bois-Reymond, a german physiologist, was the to describe "action potentials" of muscular contraction. He used a highly sensitive galvanometer, which contained more than 5 km of wire. Du Bios Reymond named the different waves: "o" was the stable equilibrium and he was the first to use the p, q, r and s to describe the different waves. ''Du Bois-Reymond, E. Untersuchungen uber thierische Elektricitat. Reimer, Berlin: 1848.''


In '''1850''' M. Hoffa described how a irregular hoe hij onregelmatige contracties van de ventrikels veroorzaakte door hondenharten een electrische schok te geven. ''Hoffa M, Ludwig C. 1850. Einige neue versuche uber herzbewegung. Zeitschrift Rationelle Medizin, 9: 107-144''  
In '''1850''' M. Hoffa described how he could induce irregular contractions of the ventricles of doghearts by administering electrical shock. ''Hoffa M, Ludwig C. 1850. Einige neue versuche uber herzbewegung. Zeitschrift Rationelle Medizin, 9: 107-144''  


In '''1887''' publiceerde de Engelse fysioloog Augustus D. Waller uit Londen het eerste menselijke electrocardiogram. Hij gebruikte een capillair-electrometer. ''Waller AD. A demonstration on man of electromotive changes accompanying the heart's beat. J Physiol (London) 1887;8:229-234''  
In '''1887''' the English physiologist Augustus D. Waller from Londen published the first human electrocardiogram. He used a capillar-electrometer. ''Waller AD. A demonstration on man of electromotive changes accompanying the heart's beat. J Physiol (London) 1887;8:229-234''  


[[wikipedia:Einthoven|Willem Einthoven]] (1860-1927) introduceerde in 1893 de term 'electrocardiogram'. Hij beschreef in '''1895''' hoe hij een galvanometer gebruikte om de electrische activiteit van het hart op te tekenen. In 1924 heeft hij hiervoor de Nobelprijs gekregen als grondlegger van het huidige ECG. Hij sloot zijn electrodes aan op de patient en liet het electrische verschil tussen twee electrodes uitschrijven door een galvanometer. Wij spreken nog steeds van de afleidingen van Einthoven. De snaar galvanometer (zie Image) werd in zijn tijd geroemd als het eerste instrument dat een klinische implicatie had.
[[wikipedia:Einthoven|The dutchman Willem Einthoven]] (1860-1927) introduced in 1893 the term 'electrocardiogram'. He described in '''1895''' how he used a galvanometer to visualize the electrical activity of the heart. In 1924 he received the Nobelprize for his work on the ECG. He connected electrodes to a patienta showed the electrical difference between two electrodes on the galvanometer. We still now use the term: Einthovens'leads. The string galvanometer (see Image) was the first clinical instrument on the recording of an ECG.


In 1905 neemt Einthoven het eerste 'telecardiogram' op vanuit het ziekenhuis naar zijn laboratorium 1,5 km verderop.
In 1905 Einthoven recorded the first 'telecardiogram' from the hospital to his laboratoy 1.5 km away.


In 1906 publiceert Einthoven het eerste artikel waarin een serie (afwijkende) ECG bevindingen worden beschreven: linker en rechter ventrikelhypertrofie, linker en rechter atriumdilatatie, de U golf, notching van het QRS comples, ventriculaire extrasystolen, bigemini, boezemflutter en totaal AV blok. ''Einthoven W. Le telecardiogramme. Arch Int de Physiol 1906;4:132-164''
In 1906 publiceert Einthoven het eerste artikel waarin een serie (afwijkende) ECG bevindingen worden beschreven: linker en rechter ventrikelhypertrofie, linker en rechter atriumdilatatie, de U golf, notching van het QRS comples, ventriculaire extrasystolen, bigemini, boezemflutter en totaal AV blok. ''Einthoven W. Le telecardiogramme. Arch Int de Physiol 1906;4:132-164''