title: QTc Prolongation in Veterans With Heroin Dependence on Methadone Maintenance Treatment.
abstract: BACKGROUND
  QTc prolongation and Torsade de Ppointes have been reported in patients on methadone maintenance.
  
  
  OBJECTIVE
  In this study, QTc was compared before and after the veteran (n = 49) was on a stable dosage of methadone for 8.72 ± 4.50 years to treat heroin dependence. Risk factors were correlated with the QTc once the veteran was on a stable dose of methadone. Differences in the clinical risk factors in subgroups of veterans with below and above mean QTc change was compared.
  
  
  METHODS
  ECG data was obtained from a 12-lead electrocardiogram (pre-methadone and on methadone) on 49 veterans. Data and risk factors were retrospectively collected from the medical records.
  
  
  RESULTS
  The mean QTc at baseline (pre-methadone) was 426 ± 34 msec and after being on methadone for an average of 8.72 ± 4.50 years was significantly higher at 450 ± 35 msec. No significant relationships were found between QTc prolongation and risk factors except for calcium. The methadone dosage was significantly higher in veterans with a QTc change above the mean change of ≥ 24 msec (88.48 ± 27.20 mg v.s 68.96 ± 19.84 mg). None of the veterans experienced cardiac arrhythmias.
  
  
  CONCLUSIONS
  The low complexity of medical co-morbidities may explain the lack of a significant correlation between any risk factor with the QTc except calcium and methadone dosage. The absence of TdP may be explained by the low prevalence of QTc values > 500 msec as well as the retrospective design of the study. During long-term methadone treatment, there was a slight increase in the QTc interval but we did not find evidence of increased cardiac toxicity as a reason for treatment termination.
authors.affiliation: Department of Psychiatry, Virginia Commonwealth University, Virginia, USA.
authors.forename: Sameer
authors.initials: S
authors.lastname: Hassamal
authors.affiliation: Department of Psychiatry, Virginia Commonwealth University, Virginia, USA ; McGuire Veterans Affairs Medical Center, Richmond, Virginia, USA.
authors.forename: Antony
authors.initials: A
authors.lastname: Fernandez
authors.affiliation: Department of Statistical Sciences, Virginia Commonwealth University, Virginia, USA.
authors.forename: Hossein
authors.initials: H
authors.lastname: Moradi Rekabdarkolaee
authors.affiliation: Department of Psychiatry, Virginia Commonwealth University, Virginia, USA.
authors.forename: Ananda
authors.initials: A
authors.lastname: Pandurangi
keywords: Arrhythmia; Heroin Dependence; Opiate Substitution Treatment; Torsades de Pointes