title: High-frequency electrocardiogram as a supplement to standard 12-lead ischemia monitoring during reperfusion therapy of acute inferior myocardial infarction.
abstract: BACKGROUND
  Resolution of ST-segment elevation in the electrocardiogram (ECG) is used as a reperfusion sign during thrombolytic therapy in acute myocardial infarction. Analysis of high-frequency QRS components (HF-QRS) might provide additional information. The study compares changes in HF-QRS (150-250 Hz) to ST-segment changes in the standard ECG during thrombolytic therapy.
  
  
  METHODS
  Twelve patients receiving intravenous thrombolytic therapy were included. A continuous 12-lead ECG recording was acquired for 4 hours.
  
  
  RESULTS
  After 1 hour of therapy, 3 patients showed ST-elevation resolution as well as an increase in HF-QRS. These changes in ST and HF-QRS occurred simultaneously. No other patient showed significant changes in ST or HF-QRS after 1 hour. After 2 and 4 hours, there was less concordance between the standard and high-frequency ECGs.
  
  
  CONCLUSIONS
  In patients with early ST-elevation resolution, the standard and high-frequency ECGs show similar results. Later changes are more disparate and may provide different clinical information.
authors.affiliation: Department of Clinical Physiology, Lund University, Lund, Sweden.
authors.forename: Jonas
authors.initials: J
authors.lastname: Pettersson
authors.forename: Galen S
authors.initials: GS
authors.lastname: Wagner
authors.forename: Leif
authors.initials: L
authors.lastname: Sörnmo
authors.forename: Elin Trägårdh
authors.initials: ET
authors.lastname: Johansson
authors.forename: Hans
authors.initials: H
authors.lastname: Ohlin
authors.forename: Olle
authors.initials: O
authors.lastname: Pahlm
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000628:therapy*; D015425:Myocardial Reperfusion / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D015912:Thrombolytic Therapy / Q000379:methods*; D016896:Treatment Outcome