title: Assessment of QT interval and QT dispersion during electroconvulsive therapy using computerized measurements.
abstract: BACKGROUND
  Electroconvulsive therapy (ECT) used in the treatment of severe psychiatric disorders induces stimulation of the autonomic nervous system with initial parasympathetic outflow immediately followed by a sympathetic response. These responses induce an initial bradycardia, arrhythmias, and hypertension. QT dispersion (QTD), defined as maximal QT interval minus minimal QT interval on 12 leads of the surface electrocardiogram, reflects regional heterogeneity of ventricular repolarization. The effects of electrical stimulus due to ECT on QT interval and QTD are of considerable interest.
  
  
  OBJECTIVE
  : This study was designed to investigate the effects of electrical stimulation caused by ECT on RR interval, QT interval, the rate-corrected QT (QTc) interval, QTD, and the rate-corrected QTD (QTcD) under general anesthesia using computerized measurements.
  
  
  METHODS
  Thirty psychiatric patients scheduled for ECT were studied under propofol anesthesia. A 12-lead electrocardiogram was monitored to measure parameters. Muscle paralysis was achieved by administering succinylcholine 1 mg/kg intravenously, and the efficacy of ECT was determined by the tourniquet technique.
  
  
  RESULTS
  The RR interval and QT interval decreased significantly immediately after electrical stimulus, and returned to the baseline level 1 minute after electrical stimulus. In 25 out of 30 patients, the baseline value of QTc interval was higher than the normal limits, and the QTc interval decreased significantly for 2 minutes after electrical stimulus. In 27 out of 30 patients, the baseline values of QTD and QTcD were higher than the normal limits, and the QTD and QTcD increased significantly from immediately after electrical stimulus to 5 minutes after electrical stimulus.
  
  
  CONCLUSIONS
  The QTc interval, QTD, and QTcD, which were associated with increased risks of ventricular arrhythmias, increased significantly before anesthetic induction in patients with major depression. Electrical stimulus during ECT induced further increases of the QTD and QTcD.
authors.affiliation: Department of Anesthesiology, and daggerDepartment of Hypertension and Cardiorenal Medicine, Dokkyo Medical University School of Medicine, Mibu, Tochigi, Japan.
authors.forename: Nobuko
authors.initials: N
authors.lastname: Tezuka
authors.forename: Hirotoshi
authors.initials: H
authors.lastname: Egawa
authors.forename: Daigo
authors.initials: D
authors.lastname: Fukagawa
authors.forename: Shigeki
authors.initials: S
authors.lastname: Yamaguchi
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Hamaguchi
authors.forename: Toshimitsu
authors.initials: T
authors.lastname: Kitajima
authors.forename: Junichi
authors.initials: J
authors.lastname: Minami
mesh_terms: D000328:Adult; D000771:Anesthesia, Intravenous; D018686:Anesthetics, Intravenous; D003201:Computers; D004562:Electrocardiography / Q000295:instrumentation* / Q000379:methods; D004565:Electroconvulsive Therapy / Q000009:adverse effects*; D005260:Female; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D006352:Heart Ventricles; D006801:Humans; D008133:Long QT Syndrome / Q000175:diagnosis* / Q000209:etiology; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D015742:Propofol
chemical_list: D018686:Anesthetics, Intravenous; D015742:Propofol