https://en.ecgpedia.org/api.php?action=feedcontributions&user=216.165.126.104&feedformat=atomECGpedia - User contributions [en]2024-03-29T10:53:53ZUser contributionsMediaWiki 1.39.5https://en.ecgpedia.org/index.php?title=Brugada_Syndrome&diff=9156Brugada Syndrome2009-06-29T22:11:49Z<p>216.165.126.104: clarify syntax</p>
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<div>{{authors|<br />
|mainauthor= [[user:Pgpostema|P.G. Postema, MD]]<br />
|supervisor=<br />
|coauthor= [[user:Drj|J.S.S.G. de Jong, MD]]<br />
|moderator= [[user:Pgpostema|P.G. Postema, MD]]<br />
|editor= <br />
}}<br />
[[Image:Brugada.png|thumb|Typical ECG abnormalities in Brugada syndrome: ST elevation in V1-V3, without ischemia.]]<br />
[[Image:Brugada_ecg_characteristics.png|thumb| Typical ECG abnormalities in Brugada syndrome]]<br />
[[Image:brugada.jpg|thumb| Dr. Pedro Brugada. Pedro and Josep Brugada described in 1992 a landmark publication with a case-series of 8 patients with sudden cardiac death. <cite>Brugada</cite> Currently, three brothers of the Brugada family (Pedro, Josep and Ramon Brugada) conduct research in the syndrome that has been named after them.]]<br />
[[Image:scn5a.jpg|thumb| The SCN5a gen is located on the short arm (p) of chromosome 3]]<br />
<br />
<br />
The '''Brugada syndrome is an hereditary disease that is associated with higher risk of sudden cardiac death'''. It is characterized by typical ECG abnormalities: '''ST segment elevation in the precordial leads (V1 - V3)'''.<br />
<br />
==Characteristics of the Brugada syndrome:==<br />
*Inheritable arrhythmia syndrome with [[w:Autosomal_dominant|autosomal dominant]] inheritance. If one of the two parents is affected, each child (both males and females) has a 50% chance of inheriting the disease.<br />
*Males are more often symptomatic than females, probably by the influence of sex hormones on cardiac arrhythmias and/or ion channels, and a different distribution of ion channels across the heart in males versus females.<br />
*The arrhythmias usually occur between 30 and 40 years of age. (range 1-77 yrs) and often during rest or while sleeping (high vagal tone).<br />
*Only in about 30% of patients, genetic defects can be detected in the ([http://ghr.nlm.nih.gov/gene=scn5a SCN5A]) gene which encodes the cardiac sodium channel (loss-of-function mutation). In much smaller quantities mutations may be found in the GPD1L gene (which probably influences cardiac sodium channel function) or in cardiac calcium channel encoding genes (CACNxxx). In the other patients, the disease is probably multi-genetic or caused by yet unknown genetic defects.<br />
*The right ventricle is most affected in Brugada syndrome, and particularly (but not specifically) the right ventricular outflow tract . <br />
*The prevalence varies between 5-50:10.000, largely depending on geographic location. In some south-east Asian countries the disease is considered endemic and believed to be the second cause of death amongst young men (after car accidents). In these countries Brugada syndrome is believed to underly (in part) the 'Sudden Unexpected Death Syndrome' (SUDS). This relation has however not been thoroughly investigated and there are almost no epidemiological studies into Brugada syndrome ECGs (apart from Japan). In different Asian countries, different names have been given to SUDS: in the Phillipines it is called ''bangungut'' (to rise and moan in sleep) and in Thailand ''lai tai'' (death during sleep). <br />
<br />
The Brugada brothers were the first to describe the characteristic ECG findings and link them to sudden death. Before that, the characteristic ECG findings, were often mistaken for a [[Right_Ventricle_MI|right ventricle myocardial infarction]] and already in 1953, a publication mentions that the ECG findings were not associated with ischemia as people often expected.<cite>osher</cite><br />
<br />
==Diagnosis and treatment==<br />
<br />
*Patients who are symptomatic (unexplained syncopes, ventricular tachycardias or aborted sudden cardiac death) may have a symptom recurrence risk of 2 to 10% per year. In these patients an [[:w:nl:Internal_Cardiac_Defibrillator|ICD]] is adviced to be implanted. Further, life-style advices are given (see below).<br />
*Some groups advice an electrophysiological investigation (inducibility of ventricular fibrillation) for risk assessment in Brugada patients,<cite>brug2</cite><cite>brug3</cite> but others could not reproduce the predictive value of these tests,<cite>priori</cite><cite>eckhardt</cite> so the value of inducibility is controversial.<br />
*In large studies familial sudden death did not appear to be a risk factor for sudden death in siblings.<br />
*In asymptomatic patients in whom the Brugada ECG characteristics are present (either spontaneously or provoked by fever or sodium channel blockers like ajmaline, procainimde or flecainide) life style advices are given, which include:<br />
**A number of medications should not be taken (amongst which sodium channel blockers such as certain anti-depressants and anti-arrhythmics, see [http://www.brugadadrugs.org www.BrugadaDrugs.org])<br />
**Rigorous treatment of fever with paracetamol / Tylenol, as fever may elicited the Brugada ECG and arrhythmias in some patients.<br />
* Spontaneous Type I ECGs do appear to be more prevalent in patients who experienced symptoms.<br />
<br />
For a full list of the diagnostic criteria, see <cite>Wilde</cite><br />
<br />
==Electrocardiographic criteria==<br />
[[Image:Brugada_lead_placement.png|thumb|Changed lead positions of leads V3 and V5 to increase the sensitiviy to 'catch' a Brugada pattern on the ECG]]<br />
Three ECG repolarization patterns in the right precordial leads are recognized in the diagnosis of Brugada syndrome.<br />
<br />
'''Type I''' is the only ECG criterion that is diagnostic of Brugada syndrome. The type I ECG is characterized by a J elevation >=2 mm (0.2 mV) a coved type ST segment followed by a negative T wave (see figure). Brugada syndrome is definitively diagnosed when a type 1 ST-segment is observed in >1 right precordial lead (V1 to V3) in the presence or absence of a sodium channel–blocking agent, and in conjunction with one of the following: <br />
*documented ventricular fibrillation (VF)<br />
*polymorphic ventricular tachycardia (VT)<br />
*a family history of sudden cardiac death at <45 years old<br />
*coved-type ECGs in family members<br />
*inducibility of VT with programmed electrical stimulation<br />
*syncope<br />
*nocturnal agonal respiration.<br />
The sensitivity of the ECG for Brugada syndrome can be increased with placement of ECG leads in the intercostal space above V1 and V2 (V1ic3 and V2ic3)<br />
<br />
Electrocardiograms of Brugada patients can change over time from type I to type II and/or normal ECGs and back.<br />
A type III ECG is rather common and is considered a normal variant, but also the Type II is a normal variant (albeit suggestive of Brugada syndrome).<br />
<br />
A recent study suggests that''' fractionation of the QRS complex''' is a marker of worse prognosis in Brugada syndrome.<cite>Morita</cite><br />
<br />
{| class="wikitable" font-size="90%"<br />
|- style="text-align:center;background-color:#6EB4EB;"<br />
|+'''ST segment abnormalities in the different types of Brugada syndrome'''<cite>Wilde2</cite><br />
|-<br />
!<br />
!Type I<br />
!Type II<br />
!Type III<br />
|- <br />
!J wave amplitude<br />
|>= 2mm<br />
|>= 2mm<br />
|>= 2mm<br />
|-<br />
!T wave<br />
|negative<br />
|positive or biphasis<br />
|positive<br />
|-<br />
!ST-T configuration<br />
|coved type<br />
|saddleback<br />
|saddleback<br />
|-<br />
!ST segment (terminal portion)<br />
|gradually descending<br />
|elevated >= 1mm<br />
|elevated < 1mm<br />
|-<br />
|}<br />
<br />
<br />
<gallery caption="Examples of Brugada syndrome type I"><br />
Image:Brugada_syndrome_type1_example1.png<br />
Image:Brugada_syndrome_type1_example2.png<br />
Image:Brugada_syndrome_type1_example3.png<br />
Image:Brugada_syndrome_type1_example4.png<br />
Image:Brugada_syndrome_type1_example5.png<br />
Image:Brugada_syndrome_type1_example6.jpg|Brugada ECG during ajmaline testing<br />
</gallery><br />
<gallery caption="Examples of Brugada syndrome type II"><br />
Image:Brugada_syndrome_type2_example1.png<br />
Image:Brugada_syndrome_type2_example2.jpg<br />
</gallery><br />
<br />
==External links==<br />
*Cardiogenetics website of the AMC [http://www.cardiogenetica.nl cardiogentica.nl]<br />
*[http://www.brugada.org Brugada.org ]<br />
*[http://www.genereviews.org/servlet/access?id=8888891&key=ghdBRjkdNXE6y&gry=INSERTGRY&fcn=y&fw=E0gK&filename=/profiles/brugada/index.html Genereview Brugada]<br />
<br />
==Referenties==<br />
<biblio><br />
#Wilde pmid=15898165<br />
#Brugada pmid=1309182<br />
#osher pmid=13104407<br />
#brug2 pmid=11772879 <br />
#brug3 pmid=12776858<br />
#priori pmid=11901046<br />
#eckhardt pmid=15642768<br />
#Wilde2 pmid=12417552<br />
#Morita pmid=18838563<br />
</biblio></div>216.165.126.104https://en.ecgpedia.org/index.php?title=Basics&diff=9155Basics2009-06-29T21:42:28Z<p>216.165.126.104: syntax correction</p>
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|previousname=Introduction<br />
|nextpage=Rate<br />
|nextname=Step 1: Heart Rate<br />
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|mainauthor= [[user:Vdbilt|I.A.C. van der Bilt, MD]]<br />
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==How do I begin to read an ECG?==<br />
[[Image:nsr.png|thumb| A short ECG registration of normal heart rhythm (sinus rhythm)]]<br />
[[Image:Normaal ecg.jpg|thumb| An example of a normal ECG. ''Click on the Image for an enlargement'']]<br />
<br />
Click on the ECG to see an enlargement.<br />
Where do you start when interpreting an ECG?<br />
* on the top left are the patient's information, name, sex and date of birth<br />
* at the right of that are below each other the [[Frequency]], the [[Conduction|conduction times]] (PQ,QRS,QT/QTc), and the [[heart axis]] (P-top axis, QRS axis and T-top axis)<br />
* further to the right is the interpretation of the ECG written (this may be missing in a 'fresh' ECG, but later the interpretation of the cardiologist or computer will be added)<br />
* down left is the 'paper speed' (25 mm/s on the horizontal axis), the sensitivity (10mm/mV) and the filter's frequency (40Hz, filters noise from eg. lights)<br />
* finally there is a calibration on the ECG, on the beginning of every lead is a vertical block that shows with what amplitude a 1 mV signal is drawn. So the height and depth of these signals are a measurement for the voltage. If this is not the set at 10 mm, there is something wrong with the machine setting.<br />
* further we have the ECG leads themselves of course, these will be discussed below.<br />
<br />
Note that the lay-out is different for every machine, but most machines will show the information above somewhere.<br />
{{clr}}<br />
<br />
==What does the ECG register?==<br />
;The electrocardiogram:An electrocardiogram (ECG or EKG) is a registration of the heart's electric activity.<br />
Just like skeletal muscles, the heart is electrically stimulated to contract. This stimulation is also called ''activation'' or ''excitation''. Cardiac muscles are electrically charged at rest. The inside of the cell is negatively charged relative to the outside (resting potential). If the cardiac muscle cells are electrically stimulated they depolarize (the resting potential changes from negative to positive) and contract. The electrical activity of a single cell can be registered as the [[action potential]].<br />
As the impulse spreads through the heart, the electric field changes continually in size and direction. The ECG is a graphical visualisation of these electric signals in the heart.<br />
<br />
==The ECG represents the sum of the action potentials of millions of cardiomyocytes==<br />
The individual [[action potential|action potentials]] of the individual cardiomyocytes are averaged. The final result which is shown on the ECG is actually the average of billions of microscopic electronical signals.<br />
During the depolarization sodium-ions stream inwards the cell. Subsequently the calcium-ions stream into the cell. These calcium-ions give the actual muscular contraction. Finally the potassium-ions stream out of the cell. During the repolarisation the ion concentration is corrected. On the ECG, an action potential wave coming towards the electrode is shown as a positive (upwards) signal. Here the ECG electrode is represented as an eye.<br />
[[Image:Ion_currents_en.png|thumb|left|300px|Ion currents of the cardiomyocytes]]<br />
[[Image:Hart_cells_en.png|thumb|right|300px|The heart consists of approximately 300 trillion cells]]<br />
[[Image:cells_in_rest_en.png|thumb|right|300px|In rest the heart cells are negatively charged. Through the depolarization by surrounding cells they become positively charged and they contract.]]<br />
<br />
{| class="wikitable" align="center" width=385px font-size="70%"<br />
|- <br />
|<flashow>http://nl.ecgpedia.org/images/5/50/Single_cardiomyocyte.swf|height=350px|width=400px</flashow><br />
|-<br />
| <small>This movie shows the contraction of a single (rabbit) heart cell. The glass electrode measures the electrical current in the heart cell (with 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, AMC, Amsterdam, The Netherlands''.</small><br />
|-<br />
|}<br />
<br />
{{clr}}<br />
<br />
==The electric discharge of the heart==<br />
[[Image:conduction_system_en.png|thumb|300px|The conduction system of the heart]]<br />
'''The sinal node (SA node) contains the fastest physiological pacemaker cells of the heart, therefore they determine the [[Rate|heart rate]].'''<br />
'''First the [[heart|atria]] depolarise and contract, after that the [[heart|ventricles]]'''<br />
The electrical signal between the atria and the ventricles goes from the sinus node, via the atria to the AV-node (atrioventricular transition) to the His bundle and subsequently to the right and left bundle branch, which end in a dense network of Purkinje fibers.<br />
The depolarization of the heart results in an electrical force which has a direction and magnitude: an electrical vector. This vector changes every millisecond of the depolarization. In the animation vectors for atrial depolarization, ventricular depolarization and ventricular repolarization are shown.<br />
<flashow>http://nl.ecgpedia.org/images/b/bc/Normal_SR_vector.swf|height=300px</flashow><br />
{{clr}}<br />
<br />
==The different ECG waves==<br />
[[File:PQRS_origin_en.png|thumb|left|300px|The origin of the different waves on the ECG]]<br />
[[Image:Epi_endo_en.png|thumb|300px| The QRS complex is formed by the sum of the electric avtivity of the inner (endocardial) and the outer (epicardial) cardiomyocytes]]<br />
[[Image:Qrs-shapes.png|thumb|300px| Example of the different QRS configurations]] <br />
The [[P_wave_morphology|'''P wave''']] is the result of the atrial depolarization. This depolarization starts in the SA (sino-atrial) node. The signal produces by pacemakercells in the SA node is conducted by the conduction system to the right and left atria. Normal atrial repolarisation is not visible on the ECG (but can be visible during [[atrial infarction]] and [[pericarditis]]). <br />
<br />
The [[QRS_morphology|'''QRS complex''' ]] is the average of the depolarization waves of the inner (endocardial) and outer (epicardial) cardiomyocytes. As the endocardial cardiomyocytes depolarize slightly earlier than the outer layers, a typical QRS pattern occurs (figure). <br />
<br />
The [[ST_morphology|'''T wave''']] represents the repolarisation of the ventricles. There is no cardiac muscle activity during the T wave.<br />
<br />
One heart beat consists of an atrial depolarization --> atrial contraction --> p-wave, ventricular depolarization --> ventricular contraction --> ORS-complex and the resting phase (including the repolarization during the T-wave) between two heart beats.<br />
<br />
Have a look at this excellent [[http://www-medlib.med.utah.edu/kw/pharm/hyper_heart1.html animation of the heart cycle]]<br />
<br />
The origin of the '''U wave''' is unknown. This wave possibly results from "afterdepolarizations" of the ventricles.<br />
<br />
The letters "Q", "R" and "S" are used to describe the QRS complex<br />
*Q: the first negative deflection after the p-wave. If the first deflection is not negative, the Q is absent.<br />
*R: the positive deflection<br />
*S: the negative deflection after the R-wave<br />
*Small print letters (q, r, s) are used to describe deflections of small amplitude. For example: qRS = small q, tall R, deep S. <br />
*R`: is used to describe a second R-wave (as in a [[RBBB|right bundle branch block]])<br />
See figure for some examples of this.<br />
<br />
{{clr}}<br />
<br />
==The history of the ECG==<br />
A [[A_Concise_History_of_the_ECG| concise history of the ECG]] is presented in a different chapter.<br />
{{clr}}<br />
<br />
==The ECG electrodes==<br />
[[Image:limb_leads.png|thumb|right|The limb leads]]<br />
[[Image:chest_leads.png|thumb|300px|right|The chest leads]]<br />
Electric activity going through the heart, can be measured by external (skin)electrodes. The electrocardiogram (ECG) registers these activities from these electrodes which have been attached on different places on the body. In total, twelve leads are calculated using ten electrodes.<br />
<br />
The ten electrodes are:<br />
<br />
* '''The four extremity electrodes:'''<br />
** LA - left arm<br />
** RA - right arm<br />
** N - neutral, on the right leg (= electrical earth or point zero to which the electrical current is measured)<br />
** F - foot, on the left leg<br />
It makes no difference whether the electrodes are attached proximal or distal on the extremities. ''However'', it is best to be uniform in this. (eg. do not attach an electrode on the left shoulder and one on the right wrist).<br />
<br />
* '''The six chest electrodes:'''<br />
** V1 - placed in the 4th intercostal space, right of the sternum<br />
** V2 - placed in the 4th intercostal space, left of the sternum<br />
** V3 - placed between V2 and V4<br />
** V4 - placed 5th intercostal space in the nippleline. Official recommendations are to place V4 under the breast in women.<cite>Kligfield</cite><br />
** V5 - placed between V4 and V6 <br />
** V6 - placed in the midaxillary line on the same height as V4 (horizontal line from V4, so not necessarily in the 5th intercostal space)<br />
<br />
{{clr}}<br />
<br />
Using these 10 electrodes, 12 leads can be derived. There are 6 extremity leads and 6 precordial leads.<br />
===The Extremity Leads===<br />
[[File:ECGafleidingen.jpg|thumb|left|200px]]<br />
The extremity leads are:<br />
<br />
*'''I''' from the right to the left arm<br />
*'''II''' from the right arm to the left leg<br />
*'''III''' from the left arm to the left leg<br />
An easy rule to remember: lead '''I''' + lead '''III''' = lead '''II'''<br />
This is done with the use of the height or depth, independent of the wave (QRS, P of T).<br />
Example: if in lead I, the QrS complex is 3 mm in height and in lead III 9mm, the height of the QRS-complex in lead II is 12mm.<br />
<br />
Other extremity leads are:<br />
<br />
*'''AVL''' points to the left arm<br />
*'''AVR''' points to the right arm <br />
*'''AVF''' points to the feet<br />
<br />
The capital A stands for "augmented" and V for "voltage".<br />
<br />
(aVR + aVL + aVF = 0)<br />
{{clr}}<br />
<br />
===The Chest Leads===<br />
The precordial, or chestleads, '''(V1,V2,V3,V4,V5 and V6)''' 'observe' the depolarization wave in the frontal plane<br />
<br />
''Example'': V1 is close to the right ventricle and the right atrium. Signals in these areas of the heart have the largest signal in this lead. V6 is the closest to the lateral wall of the left ventricle.<br />
<br />
==Special Leads==<br />
[[Image:leads_789.png|thumb|Leads V7,V8 and V9 can be helpful in the diagnosis of posterior myocardial infarction]]<br />
In case of an inferior wall infarct, extra leads may be used:<br />
#In a right side ECG, V1 and V2 remain on the same place.V3 to V6 are placed on the same place but mirrored on the chest. So V4 is in the middle of the right clavicle. On the ECG it should be marked that it is a ''Right sided ECG''. V4R (V4 but right sided) is a sensitive lead to diagnose right ventricular infarction.<br />
#Leads V7-V8-V9 can be used to diagnose a posteriorinfarct. It is means that after V6, leads are placed towards the back. See the chapter[[Ischemia]] for other ways of diagnosing posterior infarction.<br />
{{clr}}<br />
==Technical Problems==<br />
Also read the chapter about [[Technical Problems]] that helps you recognize electrical disturbance and lead reversals.<br />
{{box|<br />
==References==<br />
<biblio><br />
#Dubois Du Bois-Reymond, E. ''Untersuchungen über thierische Elektricität''. Reimer, Berlin: 1848.<br />
#Hoffa Hoffa M, Ludwig C. 1850. ''Einige neue versuche uber herzbewegung''. Zeitschrift Rationelle Medizin, 9: 107-144<br />
#Waller Waller AD. ''A demonstration on man of electromotive changes accompanying the heart's beat.'' J Physiol (London) 1887;8:229-234<br />
#Einthoven Einthoven W. ''Le telecardiogramme''. Arch Int de Physiol 1906;4:132-164<br />
#Einthoven2 Einthoven W. ''Über die Form des menschlichen Electrocardiogramms''. Pfügers Archiv maart 1895, pagina 101-123<br />
#Marey Marey EJ. ''Des variations electriques des muscles et du couer en particulier etudies au moyen de l'electrometre de M Lippman.'' Compres Rendus Hebdomadaires des Seances de l'Acadamie des sciences 1876;82:975-977 <br />
#Marquez pmid=12177632<br />
#Hurst pmid=9799216<br />
#Kligfield pmid=17322457<br />
</biblio><br />
}}<br />
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[[nl:Grondbeginselen]]<br />
[[Category:ECG Course]]</div>216.165.126.104