title: Response of QT interval in methadone maintenance treated patients to the rapid changes in heart rate provoked by brisk standing: comparison to healthy controls and patients with long QT syndrome.
abstract: BACKGROUND
  Patients on methadone maintenance therapy are somehow similar to patients with congenital long QT syndrome (LQTS) because they have malfunction of potassium channels caused by a drug that cannot be easily discontinued. We tested patients on methadone therapy with the "stand-up" test, which has been shown to unravel pathologic QT-prolongation in congenital long-QT patients.
  
  
  METHODS
  "Stand-up" test results of methadone-users, healthy volunteers and congenital LQTS patients were compared. Methadone serum levels and doses were collected. The prognostic value of the test was evaluated after 4 years of follow-up.
  
  
  RESULTS
  The QT-response of methadone-users to the "stand-up" test resembled that of healthy volunteers more than the response of LQTS-patients. Differences in the QTc of methadone treated patients and controls, which were statistically significant at baseline, became no longer significant after standing. Within 52 months of follow-up, one patient had suffered unexplained death and one had documented ventricular tachycardia.
  
  
  CONCLUSIONS
  The QT-response of methadone-users to the "stand-up" test is similar to that of healthy volunteers, not to that of LQTS-patients.
authors.affiliation: Department of Internal Medicine D, Tel-Aviv Sourasky Medical Center and Sackler-School of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Orit Kliuk
authors.initials: OK
authors.lastname: Ben Bassat
authors.forename: Einat
authors.initials: E
authors.lastname: Peles
authors.forename: Shaul
authors.initials: S
authors.lastname: Schreiber
authors.forename: Miriam
authors.initials: M
authors.lastname: Adelson
authors.forename: David
authors.initials: D
authors.lastname: Zeltser
authors.forename: Sami
authors.initials: S
authors.lastname: Viskin
authors.forename: Arnon
authors.initials: A
authors.lastname: Adler
mesh_terms: D000328:Adult; D000701:Analgesics, Opioid / Q000627:therapeutic use; D004562:Electrocardiography / Q000187:drug effects*; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D008133:Long QT Syndrome / Q000151:congenital* / Q000503:physiopathology*; D008297:Male; D008691:Methadone / Q000627:therapeutic use*; D058850:Opiate Substitution Treatment / Q000379:methods*; D011187:Posture; D012016:Reference Values
chemical_list: D000701:Analgesics, Opioid; D008691:Methadone
keywords: Long QT syndrome; Methadone