title: Electrogram characteristics in postinfarction ventricular tachycardia: effect of infarct age.
abstract: OBJECTIVE
  The purpose of this study was to correlate infarct age with characteristics of the endocardial electrograms (EGM) obtained in patients undergoing mapping procedures for postinfarction ventricular tachycardia (VT).
  
  
  BACKGROUND
  Experimental studies have demonstrated that infarct age influences EGM duration in the subepicardial left ventricle (LV). The relationship between infarct age and endocardial EGM characteristics has not been investigated in patients with postinfarction VT.
  
  
  METHODS
  In a consecutive series of 23 patients with a history of remote infarction (range 1 to 31 years) and VT, endocardial LV mapping was performed with an electroanatomical mapping system (CARTO, Biosense Webster Inc., Diamond Bar, California) during sinus rhythm. Electrogram morphology and width were analyzed and correlated with infarct age. Isthmus sites of the VT re-entry circuits were identified by entrainment mapping and related to the results of substrate mapping.
  
  
  RESULTS
  There was a significant correlation between infarct age and width of the bipolar endocardial EGM during baseline rhythm in the peri-infarct zone (r = 0.84; p < 0.0001). Increasing infarct age was associated with progressive activation delays in the scar and with isolated potentials separated by an isoelectric interval, the duration of which also correlated with infarct age (r = 0.77; p < 0.001). Among all endocardial sites, the VT isthmus sites displayed the most delay and broadest EGMs during sinus rhythm.
  
  
  CONCLUSIONS
  The presence of broad, fractionated EGMs and isolated potentials indicates a healed myocardial infarction; the older the infarction, the broader the EGM width. Remodeling over time alters the electrophysiologic properties of the peri-infarct tissue.
authors.affiliation: University of Michigan Medical Center, Ann Arbor, Michigan, USA. fbogun@umich.edu
authors.forename: Frank
authors.initials: F
authors.lastname: Bogun
authors.forename: Subramaniam
authors.initials: S
authors.lastname: Krishnan
authors.forename: Mukarram
authors.initials: M
authors.lastname: Siddiqui
authors.forename: Eric
authors.initials: E
authors.lastname: Good
authors.forename: Joseph E
authors.initials: JE
authors.lastname: Marine
authors.forename: Claudio
authors.initials: C
authors.lastname: Schuger
authors.forename: Hakan
authors.initials: H
authors.lastname: Oral
authors.forename: Aman
authors.initials: A
authors.lastname: Chugh
authors.forename: Frank
authors.initials: F
authors.lastname: Pelosi
authors.forename: Fred
authors.initials: F
authors.lastname: Morady
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D018780:Body Surface Potential Mapping; D017115:Catheter Ablation; D018450:Disease Progression; D004562:Electrocardiography; D004594:Electrophysiology; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000503:physiopathology*; D011446:Prospective Studies; D017180:Tachycardia, Ventricular / Q000175:diagnosis* / Q000503:physiopathology; D013997:Time Factors; D020257:Ventricular Remodeling / Q000502:physiology*