title: Holter monitor recording for the detection of myocardial ischemia: validation of a new recorder and chest lead positions.
abstract: OBJECTIVE
  To validate the Reynolds Tracker II Holter system using newly described lead positions during both upright treadmill exercise and in the recumbent position following exercise. The specific lead positions HL1 and HL2 were chosen to detect anterior and postero-inferior myocardial ischemia, respectively, without interfering with the surgical field in the hypothetical situation of open-heart surgery. Similar lead positions have previously been used to monitor myocardial ischemia during induction of anesthesia, but have never been validated by comparison with 12-lead modified electrocardiogram (ECG) recording.
  
  
  METHODS
  To validate the authors' 'chosen' Holter lead positions (HL1 and HL2), both at the fifth intercostal space just lateral to the midclavicular line and on the back, 1.5 cm to the left of the vertebral column, respectively) 49 candidates for routine treadmill exercise testing underwent a simultaneous Holter monitor recording using the described lead positions.
  
  
  METHODS
  The Holter ECG recordings were separately analyzed by two physicians unaware of patients' identity.
  
  
  RESULTS
  Using the modified 12-lead ECG as the 'gold standard', the sensitivity of Holter for detecting ischemia (defined as 0.1 mV or ST depression lasting at least 60 s) was 77 and 83%, and its specificity was 100 and 92%, respectively, for observers 1 and 2. Most episodes of myocardial ischemia were detected by the modified lead V5 for the 12-lead ECG and by HL1 for the Holter recording. Using the Holter Tracker II system and the chosen lead positions, it was possible to detect successfully most episodes of exercise-induced myocardial ischemia.
  
  
  CONCLUSIONS
  Holter monitoring might be useful in detecting perioperative myocardial ischemia.
authors.affiliation: Division of Cardiology, Royal Victoria Hospital, Montreal, Quebec.
authors.forename: N
authors.initials: N
authors.lastname: Racine
authors.forename: R
authors.initials: R
authors.lastname: Ripley
authors.forename: J
authors.initials: J
authors.lastname: Ramsay
authors.forename: J
authors.initials: J
authors.lastname: Silberberg
authors.forename: M H
authors.initials: MH
authors.lastname: Sami
mesh_terms: D003327:Coronary Disease / Q000175:diagnosis*; D015716:Electrocardiography, Ambulatory / Q000295:instrumentation / Q000379:methods*; D005080:Exercise Test; D006801:Humans; D015203:Reproducibility of Results