title: ST-segment deviation behavior during acute myocardial ischemia in opposite ventricular regions: observations in the intact and perfused heart.
abstract: BACKGROUND
  Acute myocardial ischemia in opposite regions may attenuate ST-segment changes, but whether this effect is expressed differently in extracardiac compared to direct intramyocardial recordings is not well known.
  
  
  OBJECTIVE
  The purpose of this study was to characterize ST-segment changes induced by opposite ischemic regions in intact and isolated perfused pig hearts.
  
  
  METHODS
  Left anterior descending (LAD) and right coronary arteries (RCA) were occluded in 7 closed chest pigs and in 5 isolated pig hearts. ST-segment changes were analyzed in 12-lead ECG and in local extracellular electrograms.
  
  
  RESULTS
  Isolated LAD or RCA occlusion induced maximal ST-segment elevation in leads V4 (0.84 ± 0.30 mV, P = .003) and III (0.16 ± 0.11 mV, P = .04), respectively. RCA occlusion also induced reciprocal ST-segment depression maximal in lead V4 (-0.40 ± 0.16 mV, P = .005). Simultaneous LAD and RCA occlusion reduced ST-segment elevation by about 60% and blunted reciprocal ST-segment changes. Reperfusion of 1 of the 2 occluded arteries induced immediate regional reversion of ST-segment elevation with concurrent beat-to-beat re-elevation in the opposite ischemic region and reappearance of reciprocal ST-segment changes. In the isolated heart, single LAD or RCA ligature induced regional transmural ST-segment elevation that was maximal in endocardial electrograms with no appreciable reciprocal ST-segment depression. Simultaneous LAD and RCA ligature reduced ST-segment elevation by about 30% with no appreciable re-elevation after 1-vessel selective reperfusion.
  
  
  CONCLUSIONS
  Acute myocardial ischemia in opposite ventricular regions attenuated ST-segment elevation and blunted reciprocal depression in conventional ECG leads but not in direct local myocardial electrograms.
authors.affiliation: Department of Cardiology, Hospital de la Santa Creu i Sant Pau, Institute of Biomedical Research IIB Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain. Electronic address: jcinca@santpau.cat.
authors.forename: Juan
authors.initials: J
authors.lastname: Cinca
authors.affiliation: Department of Cardiology, Hospital de la Santa Creu i Sant Pau, Institute of Biomedical Research IIB Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain.
authors.forename: Francisco Javier
authors.initials: FJ
authors.lastname: Noriega
authors.affiliation: Department of Cardiology, Hospital de la Santa Creu i Sant Pau, Institute of Biomedical Research IIB Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain.
authors.forename: Esther
authors.initials: E
authors.lastname: Jorge
authors.affiliation: Department of Cardiology, Hospital de la Santa Creu i Sant Pau, Institute of Biomedical Research IIB Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain.
authors.forename: Jesús
authors.initials: J
authors.lastname: Alvarez-Garcia
authors.affiliation: Department of Cardiology, Hospital de la Santa Creu i Sant Pau, Institute of Biomedical Research IIB Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain.
authors.forename: Gerard
authors.initials: G
authors.lastname: Amoros
authors.affiliation: Department of Cardiology, Hospital de la Santa Creu i Sant Pau, Institute of Biomedical Research IIB Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain.
authors.forename: Dabit
authors.initials: D
authors.lastname: Arzamendi
mesh_terms: D000818:Animals; D017023:Coronary Angiography; D054059:Coronary Occlusion / Q000503:physiopathology; D004195:Disease Models, Animal; D004562:Electrocardiography; D005260:Female; D006352:Heart Ventricles / Q000503:physiopathology*; D017202:Myocardial Ischemia / Q000503:physiopathology*; D013552:Swine
keywords: Double coronary occlusion; In situ heart; Isolated heart; Myocardial ischemia; ST-segment cancellation