LQT5: Difference between revisions
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* A prodrome may occur before losing consciousness, which may consist of [[lightheadedness]], heart [[palpitations]], [[blurred vision]] or [[weakness]]. | * A prodrome may occur before losing consciousness, which may consist of [[lightheadedness]], heart [[palpitations]], [[blurred vision]] or [[weakness]]. | ||
*[[Sudden death]] - a fatal [[arrhythmia]] that is not quickly intervened on, may cause sudden death. | *[[Sudden death]] - a fatal [[arrhythmia]] that is not quickly intervened on, may cause sudden death. | ||
* History of [[sensorineural deafness]] as occurs in [[Jervell-lange and Nielson syndrome]]/ | |||
===Therapy=== | ===Therapy=== | ||
Revision as of 09:24, 9 October 2012
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Long QT Syndrome Microchapters |
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Diagnosis |
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Treatment |
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Case Studies |
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LQT5 On the Web |
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American Roentgen Ray Society Images of LQT5 |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [2]
Overview
LQT5 subtype of long QT syndrome is an autosomal dominant mutation that leads to a defect in the potassium channel. In its rare homozygous form it can cause Jervell and Lange-Nielsen syndrome.
LQT5 Subtype
| Type | OMIM | Mutation |
| LQT5 | 176261 | beta subunit MinK (or KCNE1) which coassembles with KvLQT1 |
Genetics and Pathophysiology
LQT5 is an autosomal dominant relatively uncommon form of LQTS. It involves mutations in the gene KCNE1 which encodes for the potassium channel beta subunit MinK. In its rare homozygous forms it can lead to Jervell and Lange-Nielsen syndrome. As in LQT1, LQT5 can lead to a decreased excretion of potassium from the cell and will show prolongation of the QT interval on EKG.
History and Symptoms
- Seizures - due to oxygen deprivation that occurs during arrhythmia.
- Fainting - fainting or syncope is the most common symptom LQTS.
- A prodrome may occur before losing consciousness, which may consist of lightheadedness, heart palpitations, blurred vision or weakness.
- Sudden death - a fatal arrhythmia that is not quickly intervened on, may cause sudden death.
- History of sensorineural deafness as occurs in Jervell-lange and Nielson syndrome/
Therapy
Beta-blockers are the first line treatment in LQTS along with electrolyte repletion, and avoidance of triggers (drugs, supplements, loud noises). LQTs is one of the few diseases where genetic testing actually can provide important guidance such as who to put a AICD (defibrillator) in for primary prevention. [1] Left stellectomy) is not a cure, but is second line therapy to reduce the risk of sudden cardiac death and is indicated if the patient does not tolerate beta blockers or breaks through beta blockers, as well as in young patients under the age of 12 where beta blockers are not deemed protective enough and where the morbidity of an AICD seems excessive. Patients with long QT syndrome should undergo secondary prevention with AICD implantation for secondary prevention if they sustain an aborted cardiac arrest or sudden cardiac death.
References
- ↑ Compton SJ, Lux RL, Ramsey MR, Strelich KR, Sanguinetti MC, Green LS, Keating MT, Mason JW. Genetically defined therapy of inherited long-QT syndrome. Correction of abnormal repolarization by potassium. Circulation. 1996 Sep 1;94(5):1018-22. PMID 8790040