title: Arrhythmogenesis after acute myocardial necrosis with and without preceding ischemia in rats.
abstract: BACKGROUND
  The relative role of acute myocardial ischemia and infarction in ventricular arrhythmogenesis is incompletely understood. We compared the arrhythmia pattern after ischemia/infarction to that observed after direct myocardial necrosis without preceding ischemia in rats.
  
  
  METHODS
  Coagulation necrosis was induced in Wistar rats (n=20, 280±3 g) by radiofrequency current application (for 15 s) from a 4-mm-tip ablation catheter. Myocardial infarction was induced by coronary artery ligation with (n=10) or without (n=10) reperfusion. Using 24-h telemetry recording, we examined ventricular arrhythmias, voluntary motor activity and indices of sympathetic activation.
  
  
  RESULTS
  The coagulation-necrosis volume was 24.4%±0.6%, comparable to the infarct size in the absence of reperfusion. Acute left ventricular failure and sympathetic activation were similar in the three groups. Coagulation necrosis induced ventricular fibrillation immediately, followed by a second peak after ∼1 h. Reperfusion decreased ventricular arrhythmias, whereas a second arrhythmogenic period (between the third and the eight hour) was noted in non-reperfused infarcts (mainly monomorphic ventricular tachycardia).
  
  
  CONCLUSIONS
  Distinct arrhythmia patterns occur after myocardial infarction (with or without reperfusion) and after direct necrosis. They are not produced by differences in sympathetic activation and are likely related to the evolution of myocardial injury. The necrosis rat model may be useful in studies of arrhythmogenesis.
authors.forename: Theofilos M
authors.initials: TM
authors.lastname: Kolettis
authors.forename: Marianthi
authors.initials: M
authors.lastname: Kontonika
authors.forename: Mesele-Christina
authors.initials: MC
authors.lastname: Valenti
authors.forename: Agapi D
authors.initials: AD
authors.lastname: Vilaeti
authors.forename: Giannis G
authors.initials: GG
authors.lastname: Baltogiannis
authors.forename: Apostolos
authors.initials: A
authors.lastname: Papalois
authors.forename: Zenon S
authors.initials: ZS
authors.lastname: Kyriakides
mesh_terms: D000818:Animals; D001145:Arrhythmias, Cardiac / Q000209:etiology / Q000473:pathology*; D004195:Disease Models, Animal; D004562:Electrocardiography; D006339:Heart Rate / Q000502:physiology; D008297:Male; D009203:Myocardial Infarction / Q000150:complications / Q000473:pathology*; D015428:Myocardial Reperfusion Injury / Q000150:complications / Q000473:pathology; D009206:Myocardium / Q000473:pathology*; D009336:Necrosis; D017208:Rats, Wistar; D012720:Severity of Illness Index; D018487:Ventricular Dysfunction, Left / Q000150:complications / Q000473:pathology