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| Caption = Schematic representation of normal ECG trace ''([[sinus rhythm]]),'' with waves, segments, and intervals labeled. | | | Caption = Schematic representation of normal ECG trace ''([[sinus rhythm]]),'' with waves, segments, and intervals labeled. | |
| DiseasesDB = 11105 | | | DiseasesDB = 11105 | |
| ICD10 = | | | ICD10 = {{ICD10|R|94|3|r|94}}| |
| ICD9 = | | | ICD9 = | |
| ICDO = | | | ICDO = | |
| OMIM = | | | OMIM = | |
| MedlinePlus = | | | MedlinePlus = | |
| eMedicineSubj = |
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| eMedicineTopic = |
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| MeshID = | | | MeshID = | |
| }} | | }} |
| {{SI}} | | {{Short QT syndrome}} |
| {{CMG}}; '''Associate Editor-In-Chief:''' {{CZ}} | | {{CMG}} {{AE}}{{sumanthK}} |
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| {{SK}} SQTS; short QT; short QTc; QT interval shortening | | {{SK}} SQTS; short QT; short QTc; QT interval shortening |
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| ==Overview== | | ==[[Short_QT_syndrome_overview|Overview]]== |
| '''Short QT syndrome''' is a rare [[autosomal dominant]] inhereted disease of the electrical conduction system of the [[heart]] due to gain-of-function mutations in genes encoding for cardiac potassium channels [[KCNH2]], [[KCNQ1]] and [[KCNJ2]]. The [[QT interval]] is short (≤ 300 [[millisecond|ms]]) and does not significantly change with heart rate, and there are tall and peaked [[T waves]]. The heart is structurally normal. It is associated with an increased risk of [[atrial fibrillation]], [[syncope]] and [[sudden death]].
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| ==Historical Perspective== | | ==[[Short_QT_syndrome_historical_perspective|Historical Perspective]]== |
| The syndrome was first described by Dr. Prebe Bjerregaard MD, DMSc in 1999<ref name="pmid11173780">{{cite journal | author = Gussak I, Brugada P, Brugada J, Wright RS, Kopecky SL, Chaitman BR, Bjerregaard P | title = Idiopathic short QT interval: a new clinical syndrome? | journal = [[Cardiology]] | volume = 94 | issue = 2 | pages = 99–102 | year = 2000 | pmid = 11173780 | doi = 47299 | url = http://content.karger.com/produktedb/produkte.asp?DOI=47299 | issn = | accessdate = 2012-09-03}}</ref>.
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| ===First Patient with Short QT Syndrome=== | | ==[[Short QT syndrome classification|Classification]]== |
| Shalon Hill, a 17 year old white female, underwent laparoscopic cholecystectomy at Anderson Hospital, Maryville, Illinois in 1999 which was complicated by atrial fibrillation with a rapid ventricular response (RVR) at 150-200 beats/min along with acute [[pulmonary edema]]<ref name="pmid11173780">{{cite journal | author = Gussak I, Brugada P, Brugada J, Wright RS, Kopecky SL, Chaitman BR, Bjerregaard P | title = Idiopathic short QT interval: a new clinical syndrome? | journal = [[Cardiology]] | volume = 94 | issue = 2 | pages = 99–102 | year = 2000 | pmid = 11173780 | doi = 47299 | url = http://content.karger.com/produktedb/produkte.asp?DOI=47299 | issn = | accessdate = 2012-09-03}}</ref><ref>http://www.shortqtsyndrome.org/short_qt_history.htm</ref>. The atrial fbrillation with RVR was treated with DC [[cardioversion]] and she was discharged to home in [[normal sinus rhythm]] on [[digoxin]]. The [[atrial fibrillation]] recurred 6 weeks later and she was found at that time to have a short [[QT interval]] of 225 mseconds which was treated with prophylactic therapy with [[propafenone]]. She then remained asymptomatic for 6 months and the [[propafenone]] was discontinued. However, the atrial fibrillation recurred 2 months after the propafenone was discontinued, and it was therefore resumed. She remained asymptomatic on propafenone, but an [[AICD]] was implanted given reports from around the world of [[sudden cardiac death]].
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| ===First Family with Short QT Syndrome=== | | ==[[Short QT syndrome pathophysiology|Pathophysiology]]== |
| EKGs of the first patient's family members were analyzed. The QT interval of her 21 year old brother was 240 msec, the QT interval of her 84 year old maternal grandfather was 240 msec, and the QT interval of her 51 year old mother was 230 msec. The EKG of here father was normal<ref name="pmid11173780">{{cite journal | author = Gussak I, Brugada P, Brugada J, Wright RS, Kopecky SL, Chaitman BR, Bjerregaard P | title = Idiopathic short QT interval: a new clinical syndrome? | journal = [[Cardiology]] | volume = 94 | issue = 2 | pages = 99–102 | year = 2000 | pmid = 11173780 | doi = 47299 | url = http://content.karger.com/produktedb/produkte.asp?DOI=47299 | issn = | accessdate = 2012-09-03}}</ref>.
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| He brother was asymptomatic, and on August 13, 2003 was found to have inducible [[ventricular fibrillation ]] on programmed electrical stimulation. This was treated with implantation of an [[implantable cardioverter defibrillator]]. Subsequently he complained of occasional [[palpitations]] and [[paroxysmal atrial fibrillation]] with a rapid ventricular response was noted on interrogation of the ICD.
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| Her mother is a 51 year old healthy white female with a history of 3 episodes of sustained [[palpitations]] and [[paroxysmal atrial fibrillation]]. She has remained asymptomatic on propafenone since April, 2003. Programmed electrical stimulation on September 29, 2003 induced both atrial and [[ventricular fibrillation]] and an [[AICD]] was implanted.
| | ==[[Short QT syndrome causes|Causes]]== |
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| Her maternal grandfather was an 84 year old white male who had chronic [[atrial fibrillation]], [[coronary artery disease]] and [[hypertension]] who died following an embolic [[stroke]].
| | ==[[Short QT syndrome triggers|Triggers]]== |
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| ==Classification== | | ==[[Short QT syndrome differential diagnosis|Differentiating Short QT Syndrome from other Diseases]]== |
| *'''Short QT syndrome type 1 (SQT1):''' This variant is due to a gain-of-function mutation of the rapid component of the delayed rectifier potassium current HERG ([[KCNH2]]) channel(IKr)<ref name="pmid14676148">{{cite journal | author = Brugada R, Hong K, Dumaine R, Cordeiro J, Gaita F, Borggrefe M, Menendez TM, Brugada J, Pollevick GD, Wolpert C, Burashnikov E, Matsuo K, Wu YS, Guerchicoff A, Bianchi F, Giustetto C, Schimpf R, Brugada P, Antzelevitch C | title = Sudden death associated with short-QT syndrome linked to mutations in HERG | journal = [[Circulation]] | volume = 109 | issue = 1 | pages = 30–5 | year = 2004 | month = January | pmid = 14676148 | doi = 10.1161/01.CIR.0000109482.92774.3A | url = http://circ.ahajournals.org/cgi/pmidlookup?view=long&pmid=14676148 | issn = | accessdate = 2012-09-02}}</ref>. The variant is a result of missense mutations which increase IKr. It is associated with [[sudden death]] and [[sudden infant death syndrome]].
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| * '''Short QT syndrome type 2 (SQT2)''': Caused by a mutation in the [[KCNQ1]] gene<ref name="pmid15159330">{{cite journal | author = Bellocq C, van Ginneken AC, Bezzina CR, Alders M, Escande D, Mannens MM, Baró I, Wilde AA | title = Mutation in the KCNQ1 gene leading to the short QT-interval syndrome | journal = [[Circulation]] | volume = 109 | issue = 20 | pages = 2394–7 | year = 2004 | month = May | pmid = 15159330 | doi = 10.1161/01.CIR.0000130409.72142.FE | url = http://circ.ahajournals.org/cgi/pmidlookup?view=long&pmid=15159330 | issn = | accessdate = 2012-09-02}}</ref>. In the first patient, a g919c substitution in the [[KCNQ1]] gene encoding for the K+ channel KvLQT1 was identified. The mutation led to a gain of function in in the KvLQT1 (I(Ks)) channel. This variant is associated with [[ventricular fibrillation]].
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| * '''Short QT syndrome type 3 (SQT3)''': This variant results from a G514A substitution in the [[KCNJ2]] gene ( a change from aspartic acid to asparagine at position 172 (D172N))<ref name="pmid15761194">{{cite journal | author = Priori SG, Pandit SV, Rivolta I, Berenfeld O, Ronchetti E, Dhamoon A, Napolitano C, Anumonwo J, di Barletta MR, Gudapakkam S, Bosi G, Stramba-Badiale M, Jalife J | title = A novel form of short QT syndrome (SQT3) is caused by a mutation in the KCNJ2 gene | journal = [[Circulation Research]] | volume = 96 | issue = 7 | pages = 800–7 | year = 2005 | month = April | pmid = 15761194 | doi = 10.1161/01.RES.0000162101.76263.8c | url = http://circres.ahajournals.org/cgi/pmidlookup?view=long&pmid=15761194 | issn = | accessdate = 2012-09-02}}</ref>. This causes a defect in the gene coding for the inwardly rectifying Kir2.1 (I(K1)) channel. The ECG shows asymmetrical [[T waves]]. These patients have an increased risk for re-entry arrhythmias.
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| * '''Short QT syndrome type 3 (SQT4)''': A loss of function mutation in the [[CACNA1C]] gene alters the encoding for the α1- and β2b-subunits of the L-type calcium channel. The phenotype is similar to [[Brugada syndrome]] combined with a short QT interval. There is an increased risk of [[sudden cardiac death]].
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| * '''Short QT syndrome type 3 (SQT5)''': A loss of function mutation in the [[CACNB2B]] gene alters the encoding for the α1- and β2b-subunits of the L-type calcium channel. The phenotype is similar to [[Brugada syndrome]] combined with a short QT interval. There is an increased risk of [[sudden cardiac death]].
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| ==Pathophysiology== | | ==[[Short QT syndrome epidemiology and demographics|Epidemiology and Demographics]]== |
| It has been hypothesized that short QT syndrome is due to increased activity of outward potassium currents in phase 2 and 3 of the [[cardiac action potential]]. This would cause a shortening of the plateau phase of the action potential (phase 2), causing a shortening of the overall [[action potential]], leading to an overall shortening of refractory periods and the [[QT interval]]. In the families afflicted by short QT syndrome, two different [[missense]] [[mutation]]s have been described in the ''human ether-a-go-go [[gene]] ([[HERG]])''. These mutations result in expression of the same amino acid change in the cardiac [[cardiac action potential|I<sub>Kr</sub> ion channel]]. This mutated I<sub>Kr</sub> has increased activity compared to the normal ion channel, and would theoretically explain the above hypothesis.
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| ===Genetics=== | | ==[[Short QT syndrome screening|Screening]]== |
| In the families afflicted by short QT syndrome, [[mutation]]s have been described in three genes, [[KvLQT1]], the ''human ether-a-go-go [[gene]] ([[HERG]])'', and [[KCNJ2]]. Mutations in the ''[[KCNH2]]'', ''[[KCNJ2]]'', and ''[[KCNQ1]]'' genes cause short QT syndrome. These genes provide instructions for making proteins that act as channels across the cell membrane. These channels transport positively charged atoms (ions) of potassium into and out of cells. In cardiac muscle, these ion channels play critical roles in maintaining the heart's normal rhythm. Mutations in the ''[[KCNH2]]'', ''[[KCNJ2]]'', or ''[[KCNQ1]]'' gene increase the activity of the channels, which changes the flow of potassium ions between cells. This disruption in ion transport alters the way the heart beats, leading to the abnormal heart rhythm characteristic of short QT syndrome. Short QT syndrome appears to have an [[autosomal dominant]] pattern of inheritance.
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| Due to the [[autosomal dominant]] inheritance pattern, individuals may have family members with a history of unexplained or [[sudden death]] at a young age (even in [[infancy]]), [[palpitations]], or [[atrial fibrillation]].
| | ==[[Short QT syndrome natural history, complications and prognosis|Natural History, Complications, Prognosis]]== |
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| ==Causes== | | ==[[Diagnosis]]== |
| The causes of shortening of the [[QT interval]] can be divided into primary causes (Short QT syndrome types 1-5) and secondary causes such as drugs and electrolyte disturbances.
| | [[Short QT syndrome diagnostic criteria|Diagnostic Criteria]] | [[Short QT syndrome history and symptoms|History and Symptoms]] | [[Short QT syndrome physical examination|Physical Examination]] | [[Short QT syndrome laboratory findings|Laboratory Findings]] | [[Short QT syndrome electrocardiogram|Electrocardiogram]] | [[Short QT syndrome electrophysiologic studies|Electrophysiologic Studies]] | [[Short QT syndrome genetic testing|Genetic Testing]] |
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| ===Common Causes=== | | ==[[Treatment]]== |
| *[[Hypercalcemia]]
| | [[Short QT syndrome AICD placement|AICD placement]] | [[Short QT syndrome medical therapy|Medical Therapy]] |
| *[[Digoxin]]
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| ===Causes in Alphabetical Order===
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| * [[Acidosis]]
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| * Altered [[autonomic tone]]
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| * [[Digoxin]]
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| * [[Hypercalcaemia]]
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| * [[Hyperkalemia]]
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| * [[Hyperthermia]]
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| * [[Lanatoside C]]
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| * [[Rufinamide]]
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| * [[Short QT syndrome type 1]]
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| * [[Short QT syndrome type 2]]
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| * [[Short QT syndrome type 3]]
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| * [[Short QT syndrome type 4]]
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| * [[Short QT syndrome type 5]]
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| ===Differentiating Short QT Syndrome from other Disorders===
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| In contrast to [[Long QT Syndrome]] ([[LQTS]]), there is often no specific trigger (such as a loud noise or exercise) for an episode of [[arrhythmia]].
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| ==Epidemiology and Demographics==
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| Since the syndrome was first described in 2000, < 30 cases have been identified.
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| ===Age===
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| The median age of presentation is 30 years, but ranges from just weeks to the sixth decade of life.
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| ==Natural History, Complications, Prognosis==
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| Short QT syndrome is associated with an increased risk of [[atrial fibrillation]], [[syncope]] and [[sudden death]] due to [[ventricular fibrillation]].
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| ==Screening==
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| A young patient with [[lone atrial fibrillation]] should be assessed for [[short QT syndrome]].
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| ==Diagnosis==
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| Secondary causes of a short QT interval such as drugs and electrolyte disturbances should be ruled out before embarking on an evaluation as to whether the patient has one of the short QT syndrome variants.
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| ===Diagnostic Criteria===
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| Recent diagnostic criteria have been published out of the Arrhythmia Research Laboratory at the [[University of Ottawa Heart Institute]] from Drs. Michael H Gollob and Jason D Roberts.<ref>{{cite journal | author=Gollob M, Redpath C, Roberts J. | title= The Short QT syndrome: Proposed Diagnostic Criteria | journal=J Am Coll Cardiol | year=2011 | pages=802–812 | volume=57 | issue=7 | pmid=21310316 | doi=10.1016/j.jacc.2010.09.048}}</ref>
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| The Short QT Syndrome diagnostic criteria is based on a point system as follows:
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| *[[QTc]] in milliseconds
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| ::<370 = 1 point
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| ::<350 = 2 points
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| ::<330 = 3 points
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| *J point - T peak interval in milliseconds
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| ::<120 = 1 point
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| *Clinical History
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| ::Sudden [[cardiac arrest]] = 2 points
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| ::[[Polymorphic VT]] or [[VF]] = 2 points
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| ::Unexplained [[syncope]] = 1 point
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| ::[[Atrial fibrillation]] = 1 point
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| *Family History
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| ::1st or 2nd degree relative with SQTS = 2 points
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| ::1st or 2nd degree relative with sudden death = 1 point
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| ::Sudden infant death syndrome = 1 point
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| *Genotype
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| ::Genotype positive = 2 points
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| ::Mutation of undetermined significance in a culprit gene = 1 point
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| The points are summed and interpreted as follows:
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| *'''> or equal to 4 points:''' High-probability of SQTS
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| *'''3 Points:''' Intermediate probability of SQTS
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| *'''2 points or less:''' Low probability of SQTS
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| ===Symptoms===
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| ====Sudden Death====
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| [[Sudden death]] may be the first presentation of the disease.
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| *The most common symptom of short QT syndrome is [[cardiac arrest]] (34%)<ref name="pmid17224476">{{cite journal | author = Antzelevitch C, Pollevick GD, Cordeiro JM, Casis O, Sanguinetti MC, Aizawa Y, Guerchicoff A, Pfeiffer R, Oliva A, Wollnik B, Gelber P, Bonaros EP, Burashnikov E, Wu Y, Sargent JD, Schickel S, Oberheiden R, Bhatia A, Hsu LF, Haïssaguerre M, Schimpf R, Borggrefe M, Wolpert C | title = Loss-of-function mutations in the cardiac calcium channel underlie a new clinical entity characterized by ST-segment elevation, short QT intervals, and sudden cardiac death | journal = [[Circulation]] | volume = 115 | issue = 4 | pages = 442–9 | year = 2007 | month = January | pmid = 17224476 | pmc = 1952683 | doi = 10.1161/CIRCULATIONAHA.106.668392 | url = http://circ.ahajournals.org/cgi/pmidlookup?view=long&pmid=17224476 | issn = | accessdate = 2012-09-02}}</ref>.
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| *The first symptom of short QT syndrome is most often [[cardiac arrest]] (28%)<ref name="pmid17224476">{{cite journal | author = Antzelevitch C, Pollevick GD, Cordeiro JM, Casis O, Sanguinetti MC, Aizawa Y, Guerchicoff A, Pfeiffer R, Oliva A, Wollnik B, Gelber P, Bonaros EP, Burashnikov E, Wu Y, Sargent JD, Schickel S, Oberheiden R, Bhatia A, Hsu LF, Haïssaguerre M, Schimpf R, Borggrefe M, Wolpert C | title = Loss-of-function mutations in the cardiac calcium channel underlie a new clinical entity characterized by ST-segment elevation, short QT intervals, and sudden cardiac death | journal = [[Circulation]] | volume = 115 | issue = 4 | pages = 442–9 | year = 2007 | month = January | pmid = 17224476 | pmc = 1952683 | doi = 10.1161/CIRCULATIONAHA.106.668392 | url = http://circ.ahajournals.org/cgi/pmidlookup?view=long&pmid=17224476 | issn = | accessdate = 2012-09-02}}</ref>
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| ====Syncope====
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| *[[Syncope]] is the first symptom in 24% of patients and is most likely due to self-terminating [[ventricular fibrillation]].
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| ====Palpitations====
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| *[[Palpitations]] are present in 31% of patients.
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| ====Atrial Fibrillation====
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| *[[Atrial fibrillation]] is present in up to 80% of patients with short QT syndrome.
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| ====Triggers====
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| In contrast to [[Long QT Syndrome]] ([[LQTS]]), there is often no specific trigger (such as a loud noise or exercise) for an episode of [[arrhythmia]].
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| ==Screening==
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| Short QT syndrome should be excluded in patients without structural heart disease presenting with sudden cardiac death. | |
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| ===Electrocardiogam===
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| [[Image:Short qt.jpg|Frame|Right|Thumb|Tall peaked T wave and short QT in the right precordial lead V2]]
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| The characteristic findings of short QT syndrome on [[EKG]] are a short [[QT interval]], typically ≤ 300-320 ms, that doesn't significantly change with the heart rate. Tall, peaked [[T waves]] in the right precordial leads may also be noted. 70% of patients with short QT have a history of either [[paroxysmal atrial fibrillation]] or [[permanent atrial fibrillation]], and [[atrial fibrillation]] is the first sign of short QT syndrome in 50% of patients. In young patients with [[lone atrial fibrillation]], the patient should be screened for short QT syndrome.
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| ===Electrophysiologic Studies===
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| In the electrophysiology lab, individuals with short QT syndrome are noted to have short refractory periods (ranging from 120 to 180 ms), both in the [[atrium (anatomy)|atria]] as well as in the [[Ventricle (heart)|ventricles]]. [[Ventricular fibrillation]] is induced on [[programmed stimulation]] in 90% of patients with short QT syndrome. Despite the high rate of VF inducibility, the risk of sudden death in an individual patient is difficult to predict given the genetic and clinical heterogeneity of short QT syndrome and the limited number of patients with short follow-up to date.
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| ===Genetic Testing===
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| Mutations in the ''[[KCNH2]]'', ''[[KCNJ2]]'', and ''[[KCNQ1]]'' genes cause short QT syndrome. These genes provide instructions for making proteins that act as channels across the cell membrane. These channels transport positively charged atoms (ions) of potassium into and out of cells. In [[cardiac muscle]], these ion channels play critical roles in maintaining the heart's normal rhythm. Mutations in the ''KCNH2'', ''KCNJ2'', or ''KCNQ1'' gene increase the activity of the channels, which changes the flow of potassium ions between cells. This disruption in ion transport alters the way the heart beats, leading to the abnormal heart rhythm characteristic of short QT syndrome. Short QT syndrome appears to have an autosomal dominant pattern of inheritance.
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| ====Centers Performing Genetic Testing for Short QT Syndrome====
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| *[http://ghr.nlm.nih.gov/exit?to=www.ncbi.nlm.nih.gov&vje=7bH4sIAAAAAAAAABXKMQrDMAwF0KvkBFZKITTdCoVOzZRdOLZoPjhyiUS99PAhb36paoajKs-7RN9EnZ.To5vFnN..1f17J2qtBU0LgpYtKNbwqT8yuBi9ROXMRiUulAoUKRbOMIkmjEzXy9jfhgNml6ZqaQAAAA__ Gene Tests: Short QT Syndrome 1]
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| *[http://ghr.nlm.nih.gov/exit?to=www.ncbi.nlm.nih.gov&vje=7bH4sIAAAAAAAAABXKMQ6DMAwF0KtwgpiqA6VbpUqdysRuhcQqXwpOha1m6eERb36paoajKs-7RN9EnZ.To5vFnN..1f17J2qtBU0LgpYtKNbwqT8yuBi9ROXMRiUulAoUKRbOMIkmjEzXy9jfhgPwp6EdaQAAAA__ Gene Tests: Short QT Syndrome 2]
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| *[http://ghr.nlm.nih.gov/exit?to=www.ncbi.nlm.nih.gov&vje=7bH4sIAAAAAAAAABXKMQ7CMAwF0Kv0BHERS-lWCYkJpu5WmljNl1IH1RZZODzizS81zXA05fWU6Ieo8.21DKuY8.Nb3N8zUe89aNoQtB5BUcLePmRwMXqIyj8b1bhRqlCkWDnDJJowMl0vt3GafmG6Ho1pAAAA Gene Tests: Short QT Syndrome 3]
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| ==Treatment==
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| ===Device Based Therapy===
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| An [[implantable cardioverter-defibrillator]] ([[ICD]]) is indicated in<ref>Borggrefe M. FESC, Wolpert C, Veltmann C, Giustetto C, Gaita F, Schimpf R. Short QT Syndrome : A new primary electrical disease, ESC E journal, Vol 3 N°34, 10 May 2005. [http://www.escardio.org/communities/councils/ccp/e-journal/volume3/Pages/vol3n34.aspx]</ref>:
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| *Symptomatic patients
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| *Patients with a family history of [[sudden cardiac death]]
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| ===Pharmacologic Therapy===
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| ====Short QT Syndrome 1 (SQT1)====
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| Patients with Short QT Syndrome 1 (SQT1) have a mutation in [[KCNH2]] ([[HERG]]). Class IC and III antiarrhythmic drugs do not produce any significant QT interval prolongation <ref>{{cite journal | author=Gaita F, Giustetto C, Bianchi F, Schimpf R, Haissaguerre M, Calo L, Brugada R, Antzelevitch C, Borggrefe M, Wolpert C. | title=Short QT syndrome: pharmacological treatment | journal=J Am Coll Cardiol | year=2004 | pages=1494–1499 | volume=43 | issue=8 | pmid=15093889 | doi=10.1016/j.jacc.2004.02.034}}</ref><ref name="pmid15673388">{{cite journal | author = Wolpert C, Schimpf R, Giustetto C, Antzelevitch C, Cordeiro J, Dumaine R, Brugada R, Hong K, Bauersfeld U, Gaita F, Borggrefe M | title = Further insights into the effect of quinidine in short QT syndrome caused by a mutation in HERG | journal = [[Journal of Cardiovascular Electrophysiology]] | volume = 16 | issue = 1 | pages = 54–8 | year = 2005 | month = January | pmid = 15673388 | pmc = 1474841 | doi = 10.1046/j.1540-8167.2005.04470.x | url = http://onlinelibrary.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=1045-3873&date=2005&volume=16&issue=1&spage=54 | issn = | accessdate = 2012-09-03}}</ref> .
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| In four out of four patients, [[Quinidine]] prolonged the [[QT interval]] from 263 +/- 12 msec to 362 +/-25 msec, most likely due to its effects on prolonging the [[action potential]] and by virtue of its action on the I<sub>K</sub> channels. Although [[Quinidine]] was successful in preventing the inducibility of [[ventricular fibrillation]] in 4 out of 4 patients, it is unclear if the prolongation of the [[QT interval]] by [[quinidine]] would reduce the risk of [[sudden cardiac death]]. Although pharmacotherapy can be used to suppress the occurrence of [[atrial fibrillation]] in patients with SQT1, [[AICD]] implantation is the mainstay of therapy, and pharmacotherapy to prevent sudden death should is only indicated if [[AICD]] implantation is not possible.
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| ==References==
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| {{Reflist|2}}
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| {{Electrocardiography}} | | {{Electrocardiography}} |
