title: Acquired long QT syndrome: frequency, onset, and risk factors in intensive care patients.
abstract: BACKGROUND
  Acquired long QT syndrome is a reversible condition that can lead to torsades de pointes and sudden cardiac death.
  
  
  OBJECTIVE
  To determine the frequency, onset, frequency of medications, and risk factors for the syndrome in intensive care patients.
  
  
  METHODS
  In a retrospective chart review of 88 subjects, hourly corrected QT intervals calculated by using the Bazett formula were collected. Acquired long QT syndrome was defined as a corrected QT of 500 milliseconds or longer or an increase in corrected QT of 60 milliseconds or greater from baseline level. Risk factors and medications administered were collected from patients' medical records.
  
  
  RESULTS
  The syndrome occurred in 46 patients (52%); mean time of onset was 7.4 hours (SD, 9.4) from time of admission. Among the 88 patients, 52 (59%) received a known QTc-prolonging medication. Among the 46 with the syndrome, 23 (50%) received a known QT-prolonging medication. No other risk factor studied was significantly predictive of the syndrome.
  
  
  CONCLUSIONS
  Acquired long QT syndrome occurs in patients not treated with a known QT-prolonging medication, indicating the importance of frequent QT monitoring of all intensive care patients.
authors.affiliation: Cardiac Research Department, Saint Joseph's Medical Center, Stockton, CA 95204, USA. teri.kozik@dignityhealth.org
authors.forename: Teri M
authors.initials: TM
authors.lastname: Kozik
authors.forename: Shu-Fen
authors.initials: SF
authors.lastname: Wung
mesh_terms: D000368:Aged; D003422:Critical Care / Q000706:statistics & numerical data; D064420:Drug-Related Side Effects and Adverse Reactions; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D016015:Logistic Models; D008133:Long QT Syndrome / Q000139:chemically induced* / Q000150:complications / Q000175:diagnosis; D008297:Male; D008875:Middle Aged; D004364:Pharmaceutical Preparations / Q000008:administration & dosage; D012189:Retrospective Studies; D012307:Risk Factors
chemical_list: D004364:Pharmaceutical Preparations