QT interval

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Revision as of 22:39, 12 January 2009 by imported>Robert Badgett (Started Congenital Long QT Syndrome)
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In cardiology and the electrocardiogram, the QT interval is the time from the start of the Q wave and the end of the T wave.

To correct the QT interval for heart rate:

Normal values for the corrected QT interval are between 0.36 and 0.44 seconds.

A prolonged QT internal may lead to Torsades de pointes. Drugs may prolong the QT interval.[1] A list of these drugs is available at the Arizona Center for Education & Research on Therapeutics.

Congenital Long QT Syndrome

Andersen Syndrome

Andersen Syndrome is a "form of inherited long QT syndrome (or LQT7) that is characterized by a triad of potassium-sensitive periodic paralysis, ventricular ectopic beats, and abnormal features such as short stature, low-set ears, and scoliosis. It results from mutations of KCNJ2 gene which encodes a channel protein (inward rectifier potassium channels) that regulates resting membrane potential."[2][3]

Jervell-Lange Nielsen Syndrome

Jervell-Lange Nielsen Syndrome is a "form of long QT syndrome that is associated with congenital deafness. It is characterized by abnormal cardioelectrophysiology involving the voltage-gated potassium channel. It results from mutation of KCNQ1 gene (Subtype 1 or JLN1) or the KCNE1 gene (Subtype 2 or JLN2).."[4][5][6]

Romano-Ward Syndrome

Romano-Ward Syndrome (LQT1) is a "form of long QT syndrome that is without congenital deafness. It is caused by mutation of the KCNQ1 gene which encodes a protein in the voltage-gated potassium channel."[7][8]

References

  1. Roden DM (March 2004). "Drug-induced prolongation of the QT interval". N. Engl. J. Med. 350 (10): 1013–22. DOI:10.1056/NEJMra032426. PMID 14999113. Research Blogging.
  2. Anonymous (2024), Andersen Syndrome (English). Medical Subject Headings. U.S. National Library of Medicine.
  3. Online Mendelian Inheritance in Man, OMIM®. Johns Hopkins University, Baltimore, MD. MIM Number: 170390. World Wide Web URL: http://omim.org/.
  4. Anonymous (2024), Jervell-Lange Nielsen Syndrome (English). Medical Subject Headings. U.S. National Library of Medicine.
  5. Online Mendelian Inheritance in Man, OMIM®. Johns Hopkins University, Baltimore, MD. MIM Number: 220400. World Wide Web URL: http://omim.org/.
  6. Online Mendelian Inheritance in Man, OMIM®. Johns Hopkins University, Baltimore, MD. MIM Number: 612347. World Wide Web URL: http://omim.org/.
  7. Anonymous (2024), Romano-Ward Syndrome (English). Medical Subject Headings. U.S. National Library of Medicine.
  8. {{OMIM|192500}