Editing Brugada syndrome (section)

=== Electrocardiography ===
[[Image:Brugada.jpg|right|thumb|upright=1.6|ECG pattern in Brugada syndrome. According to consensus guidelines, Type 1 ST segment elevation, either spontaneously present or induced with the sodium channel-blocker challenge test, is considered diagnostic. Type 2 and 3 may lead to suspicion, but provocation testing is required for diagnosis. The ECGs in the right and left panels are from the same patient before (right panel, type 3) and after (left panel, type 1) administration of Ajmaline.]]

Brugada syndrome is diagnosed by identifying characteristic patterns on an [[Electrocardiography|electrocardiogram]].<ref name="Postema_2009" /> The pattern seen on the ECG includes [[ST elevation]] in leads V<sub>1</sub>-V<sub>3</sub> with a [[right bundle branch block]] (RBBB) appearance. There may be evidence of a slowing of electrical conduction within the heart, as shown by a prolonged [[PR interval]]. These patterns may be present all the time, but may appear only in response to particular drugs (see below), when the person has a [[fever]], during exercise, or as a result of other triggers. The ECG pattern may become more obvious by performing an ECG in which some of the electrodes are placed in different positions from usual, specifically by placing leads V<sub>1</sub> and V<sub>2</sub> higher up the chest wall in the 1st or 2nd intercostal spaces.<ref name="Obeyesekere_2011" />

Three forms of the Brugada ECG pattern have historically been described,<ref name=":3">{{Cite journal|last1=Wilde|first1=A. a. M.|last2=Antzelevitch|first2=C.|last3=Borggrefe|first3=M.|last4=Brugada|first4=J.|last5=Brugada|first5=R.|last6=Brugada|first6=P.|last7=Corrado|first7=D.|last8=Hauer|first8=R. N. W.|last9=Kass|first9=R. S.|last10=Nademanee|first10=K.|last11=Priori|first11=S. G.|date=November 2002|title=Proposed diagnostic criteria for the Brugada syndrome|journal=European Heart Journal|volume=23|issue=21|pages=1648–1654|doi=10.1053/euhj.2002.3382|issn=0195-668X|pmid=12448445|doi-access=free}}</ref> although the Type 3 pattern is frequently merged with the Type 2 pattern in contemporary practice.<ref name=":4">{{Cite journal|last1=Bayés de Luna|first1=Antonio|last2=Brugada|first2=Josep|last3=Baranchuk|first3=Adrian|last4=Borggrefe|first4=Martin|last5=Breithardt|first5=Guenter|last6=Goldwasser|first6=Diego|last7=Lambiase|first7=Pier|last8=Riera|first8=Andrés Pérez|last9=Garcia-Niebla|first9=Javier|last10=Pastore|first10=Carlos|last11=Oreto|first11=Giuseppe|date=September 2012|title=Current electrocardiographic criteria for diagnosis of Brugada pattern: a consensus report|url=https://pubmed.ncbi.nlm.nih.gov/22920782|journal=Journal of Electrocardiology|volume=45|issue=5|pages=433–442|doi=10.1016/j.jelectrocard.2012.06.004|issn=1532-8430|pmid=22920782}}</ref>
* Type 1 has a coved type ST elevation with at least 2&nbsp;mm (0.2 mV) [[QRS complex#J-point|J-point]] elevation and a gradually descending [[ST segment]] followed by a negative [[T wave|T-wave]].<ref name=":4" />
* Type 2 has a saddle-back pattern with at least 2&nbsp;mm J-point elevation and at least 0.5&nbsp;mm elevation of the terminal ST segment with a positive or biphasic T-wave.<ref name=":4" /> A type 2 pattern can occasionally be seen in healthy subjects.
* Type 3 has  a saddle-back (type 2 like) pattern, with at least 2&nbsp;mm J-point elevation but less than 1&nbsp;mm elevation of the terminal ST segment.<ref name=":3" /> 
According to current recommendations, only a Type 1 ECG pattern, occurring either spontaneously or in response to medication, can be used to confirm the diagnosis of Brugada syndrome as Type 2 and 3 patterns are not infrequently seen in persons without the disease.<ref name = Pri2013/>