title: Signal-averaged ECG prior to and serially after thrombolytic therapy for acute myocardial infarction.
abstract: Signal averaging has been performed to evaluate late potentials following infarction and the administration of thrombolytic therapy. Most studies have recorded signal-averaged electrocardiograms (SAECGs) at least 12 hours after the onset of the infarction. In this study, SAECGs were recorded before thrombolytic therapy and serially over 7-10 days following infarction in 21 patients. The high frequency QRS duration was significantly shortened at 1 and 24 hours compared to presentation (96.8 +/- 11.3 ms and 93.4 +/- 8.0 ms vs 103.3 +/- 14.3 ms, respectively, P < 0.05) and there was an increase in the terminal voltage over time, significant at 1 hour and 3 days (57.3 +/- 29.1 microV and 58.6 +/- 44.7 microV vs 44.4 +/- 35.5 microV, respectively, P < 0.01). Five patients met criteria for ventricular late potentials on at least one SAECG. The prevalence of late potentials was higher in patients with Q wave infarctions, or with occluded infarct related arteries. These changes in myocardial activation may be related to ischemia and reperfusion, and may not correlate with the development of a fixed substrate for reentry.
authors.affiliation: Department of Medicine, Cooper Hospital/University Medical Center, UMDNJ/Robert Wood Johnson Medical School, Camden, USA.
authors.forename: L A
authors.initials: LA
authors.lastname: Beauregard
authors.forename: H L
authors.initials: HL
authors.lastname: Waxman
authors.forename: R
authors.initials: R
authors.lastname: Volosin
authors.forename: K J
authors.initials: KJ
authors.lastname: Volosin
authors.forename: P B
authors.initials: PB
authors.lastname: Kurnik
mesh_terms: D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000188:drug therapy / Q000503:physiopathology*; D010960:Plasminogen Activators / Q000627:therapeutic use; D011446:Prospective Studies; D012815:Signal Processing, Computer-Assisted; D015912:Thrombolytic Therapy; D013997:Time Factors; D010959:Tissue Plasminogen Activator / Q000627:therapeutic use; D016276:Ventricular Function
chemical_list: D010960:Plasminogen Activators; D010959:Tissue Plasminogen Activator