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| {{Infobox Disease | | | {{Infobox Disease | |
| Name = Short QT syndrome | | | Name = Short QT syndrome | |
| Image = | | | Image = SinusRhythmLabels.svg | |
| Caption = | | | 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 = | |
| }} | | }} |
| {{Short QT syndrome}} | | {{Short QT syndrome}} |
| {{CMG}} | | {{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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| ==[[Short QT syndrome natural history, complications and prognosis|Natural History, Complications, Prognosis]]== | | ==[[Short QT syndrome natural history, complications and prognosis|Natural History, Complications, Prognosis]]== |
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| ==Diagnosis== | | ==[[Diagnosis]]== |
| [[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 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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| [[Short QT syndrome genetic testing|Genetic Testing]]
| | ==[[Treatment]]== |
| | | [[Short QT syndrome AICD placement|AICD placement]] | [[Short QT syndrome medical therapy|Medical Therapy]] |
| ==Treatment== | |
| ===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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| Generally accepted criteria for implantation of an [[AICD]] also include:
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| *Inducibility on electrophysiologic testing
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| *Positive genetic test, although a negative result does not exclude the presence of a previously unreported mutation or the occurrence of a future arrhythmic event
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| ====Complications of AICD Placement====
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| Inappropriate shocks may be delivered due to<ref>Schimpf R, Wolpert C, Bianchi F, et al. Congenital Short QT Syndrome and Implantable Cardioverter Defibrillator Treatment: Inherent Risk for Inappropriate Shock Delivery. J Cardiovasc Electrophysiol 2003; 14: 1273-1277.</ref>:
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| *The occurence of tachycardias such as [[sinus tachycardia]] and [[atrial fibrillation]].
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| *Oversensing of the tall, narrow peaked [[T wave]]
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| ===Pharmacologic Therapy===
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| ====Short QT Syndrome 1 (SQT1)====
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| The efficacy of pharmacotherapy in preventing [[ventricular fibrillation]] has only been studies in patients with SQT1. Given the limited number of patients studied, and the limited duration of follow-up, pharmacotherapy as primary or secondary preventive therapy for patients with SQT1 cannot be recommended at this time. [[AICD]] implantation remains the mainstay of therapy in these patients. Pharmacotherapy may play an adjunctive role in reducing the risk of events in patients with an [[AICD]] as described below in the indications section.
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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> . Flecainide has not been shown to consistently reduce the inducibility of [[ventricular fibrillation]].<ref name="pmid15093889">{{cite journal | author = Gaita F, Giustetto C, Bianchi F, Schimpf R, Haissaguerre M, Calò L, Brugada R, Antzelevitch C, Borggrefe M, Wolpert C | title = Short QT syndrome: pharmacological treatment | journal = [[Journal of the American College of Cardiology]] | volume = 43 | issue = 8 | pages = 1494–9 | year = 2004 | month = April | pmid = 15093889 | doi = 10.1016/j.jacc.2004.02.034 | url = http://linkinghub.elsevier.com/retrieve/pii/S0735109704004437 | issn = | accessdate = 2012-09-03}}</ref> Although it does not prolong the [[QT interval]] in SQT1 patients, [[propafenone]] reduces the risk of recurrent [[atrial fibrillation]] in SQT1 patients.<ref> Bjerregaard P, Gussak I. Atrial fibrillation in the setting of familial short QT interval. Heart Rhythm 2004; 1: S165 (abstract).</ref>
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| Quinidine in contrast may be effective in patients with SQT1 in so far as it blocks both potassium channels (IKr, IKs, Ito, IKATP and IK1) and the inward sodium and calcium channels. 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]].
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| 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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| Among patients with SQT1, [[Qunidine ]]also:
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| *Prolongs the [[ST segment]] and [[T wave]] durations
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| *Restores the [[heart rate]] dependent variability in the [[QT interval]]
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| *Decreases repolarization dispersion
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| ====Indications for Pharmacologic Therapy====
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| The following are indications for pharmacologic therapy of SQTS<ref>Moreno-Reviriego S, Merino JL.Short QT Syndrome. An article from the E-Journal of the ESC Council for Cardiology Practice. Vol9 N°2, 17 Sep 2010 [http://www.escardio.org/communities/councils/ccp/e-journal/volume9/Pages/Short_Qt_Syndrome_Reviriego.aspx]</ref>:
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| * In children as an alternate to [[AICD]] implantation
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| * In patients with a contraindications [[AICD]] implantation
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| * In patients who decline [[AICD]] implantation
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| * In patients with appropriate [[AICD]] discharges to reduce the frequency of discharges
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| * In patients with [[atrial fibrillation]] to reduce the frequency of symptomatic episodes
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| ==References==
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| {{Reflist|2}}
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| {{Electrocardiography}} | | {{Electrocardiography}} |
