title: QT dispersion and rate-corrected QT dispersion during electroconvulsive therapy in elderly patients.
abstract: BACKGROUND
  Electroconvulsive therapy (ECT) induces increase of QT dispersion (QTD) and the rate-corrected QTD (QTcD), which are associated with increased risk of ventricular arrhythmias and cardiovascular mortality. The effects of electrical stimulus during ECT on QTD and QTcD in elderly patients are of considerable interest.
  
  
  OBJECTIVE
  The purpose of this study was to clarify the differential effects of electrical stimulus caused by ECT on interbeat interval, QT interval, the rate-corrected QT (QTc) interval, QTD, and the QTcD under propofol anesthesia between younger and elderly patients with major depression.
  
  
  METHODS
  Twenty younger psychiatric patients (aged 30-40 years) and 20 elderly patients (aged 65-75 years) scheduled for ECT were studied under propofol anesthesia. A 12-lead electrocardiogram was monitored to measure parameters. Muscle paralysis was achieved by administering 1-mg/kg succinylcholine intravenously, and the efficacy of ECT was determined by the tourniquet technique.
  
  
  RESULTS
  The mean arterial pressure in the elderly was significantly higher than that of the younger patients from immediately to 2 minutes after electrical stimulus. The interbeat interval in the elderly was significantly lower than that of the younger patients from immediately to 1 minute after electrical stimulus. There was no statistically significant difference in the QT interval between the groups. The baseline value of QTc interval was higher than the normal limits, and the QTc interval in the elderly was significantly lower than that of the younger patients from immediately to 1 minute after electrical stimulus. The baseline value of QTD was higher than the normal limits, and the QTD in the elderly was significantly higher than that of the younger patients from immediately to 7 minutes after electrical stimulus. The baseline value of QTcD was higher than the normal limits, and the QTcD in the elderly was significantly higher than that of the younger patients from immediately to 7 minutes after electrical stimulus.
  
  
  CONCLUSIONS
  The QTc interval, QTD, and QTcD may be higher than the normal limits before anesthesia in patients with major depression. The QTD and QTcD in the elderly, which are associated with increased risks of ventricular arrhythmias, are higher than those of the younger patients after electrical stimulus during ECT. Electrical stimulus may induce further increased risks of cardiac events in elderly patients.
authors.affiliation: Department of Anesthesiology, Dokkyo Medical University School of Medicine, Mibu, Tochigi, Japan. shigeki@dokkyomed.ac.jp
authors.forename: Shigeki
authors.initials: S
authors.lastname: Yamaguchi
authors.forename: Masaru
authors.initials: M
authors.lastname: Nagao
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Ikeda
authors.forename: Daigo
authors.initials: D
authors.lastname: Fukagawa
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Kimura
authors.forename: Toshimitsu
authors.initials: T
authors.lastname: Kitajima
authors.forename: Junichi
authors.initials: J
authors.lastname: Minami
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D000768:Anesthesia, General; D001145:Arrhythmias, Cardiac / Q000453:epidemiology; D001794:Blood Pressure / Q000502:physiology; D002318:Cardiovascular Diseases / Q000401:mortality; D003865:Major Depressive Disorder / Q000628:therapy; D004562:Electrocardiography / Q000706:statistics & numerical data*; D004565:Electroconvulsive Therapy / Q000009:adverse effects*; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008133:Long QT Syndrome / Q000209:etiology; D008297:Male; D009467:Neuromuscular Depolarizing Agents; D011619:Psychotropic Drugs / Q000009:adverse effects / Q000627:therapeutic use; D018570:Risk Assessment; D013390:Succinylcholine; D018879:Ventricular Premature Complexes / Q000209:etiology
chemical_list: D009467:Neuromuscular Depolarizing Agents; D011619:Psychotropic Drugs; D013390:Succinylcholine