title: Underestimated and unreported prolonged QTc by automated ECG analysis in patients on methadone: can we rely on computer reading?
abstract: BACKGROUND
  Recognition of prolonged corrected QT (QTc) interval is of particular importance, especially when using medications known to prolong QTc interval. Methadone can prolong the QTc interval and has the potential to induce torsades de pointes.
  
  
  OBJECTIVE
  The objective of this study is to investigate the accuracy of computerized ECG analysis in correctly identifying and reporting QTc interval in patients on methadone.
  
  
  METHODS
  We conducted a retrospective review of ECGs in the Muse electronic database of patients on methadone who are above 18 years old between January 2012 and December 2013 at an urban community hospital. ECGs were analyzed by the Marquette 12SL ECG Analysis Program (GE'Healthcare) reviewed by a cardiologist.
  
  
  RESULTS
  A total of 826 ECGs of patients on methadone were examined manually for the QTc interval, of which 625 (75.7%) had QTc less than 470 ms, 149 (18%) had QTc between 470-499 ms and 52 (6.3%) had QTc more than 499 ms. QTc between 470-499 ms was underestimated by machine in 19 (12.8%) ECGs and QTc more than 499 ms was underestimated in 10 (19.6%) when compared to manually calculated QTc. QTc prolongation was underreported in 63 ECGs (48.5%) of those whose QTc between 470-499 ms and in 1 ECG (2.4%) of those whose QTc was more than 499 ms.
  
  
  CONCLUSIONS
  QTc can be underestimated or unreported by the computer analysis. Physicians not only should calculate QTc manually but also examine the actual QTc value displayed on the report before concluding that this parameter is normal, especially in patients who are at risk of QTc prolongation.
authors.forename: Soheila
authors.initials: S
authors.lastname: Talebi
authors.forename: Alaleh
authors.initials: A
authors.lastname: Azhir
authors.forename: Sam
authors.initials: S
authors.lastname: Zuber
authors.forename: Sandeep
authors.initials: S
authors.lastname: Soman
authors.forename: Ferdinand
authors.initials: F
authors.lastname: Visco
authors.forename: Holly
authors.initials: H
authors.lastname: Totouom-Tangho
authors.forename: Hossein
authors.initials: H
authors.lastname: Kalantar
authors.forename: Getaw
authors.initials: G
authors.lastname: Worku Hassen
mesh_terms: D000701:Analgesics, Opioid / Q000009:adverse effects / Q000627:therapeutic use; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D003951:Diagnostic Errors / Q000706:statistics & numerical data*; D004562:Electrocardiography / Q000187:drug effects* / Q000379:methods*; D005260:Female; D006801:Humans; D008133:Long QT Syndrome / Q000139:chemically induced / Q000175:diagnosis* / Q000503:physiopathology; D008297:Male; D008691:Methadone / Q000009:adverse effects / Q000627:therapeutic use*; D008875:Middle Aged; D010146:Pain / Q000188:drug therapy* / Q000503:physiopathology; D012189:Retrospective Studies
chemical_list: D000701:Analgesics, Opioid; D008691:Methadone