title: Phase 2 reentry in man.
abstract: BACKGROUND
  Ventricular extrasystoles are characterized by a fixed coupling interval to the last QRST complex preceding it.
  
  
  OBJECTIVE
  We hypothesized that this QRST complex differed from QRST complexes of other sinus beats not followed by ventricular extrasystoles. Further, we investigated whether phase 2 reentry, demonstrated in animal experiments to initiate ventricular extrasystoles, ventricular tachycardia, and ventricular fibrillation, also plays a role in humans.
  
  
  METHODS
  We examined 18 patients with ventricular extrasystoles and/or ventricular tachycardia by signal averaging of the ECG (group A) or by single-beat analysis of intracardiac electrograms (group B). Group A consisted of six patients without structural heart disease and one patient with the Brugada syndrome. Six of the seven patients had right ventricular outflow tract ventricular extrasystoles. Group B consisted of 11 patients undergoing radiofrequency ablation. Eight of the 11 patients had right ventricular outflow tract extrasystoles.
  
  
  RESULTS
  In six of the seven patients in group A, we demonstrated significant ST-elevation and/or T-wave changes in the sinus beat preceding ventricular extrasystoles compared with the second last sinus beat in one or more of the three orthogonal leads X, Y, and Z. In 9 of the 11 patients in group B, single-beat analysis of unipolar and bipolar electrograms recorded close to successful ablation sites demonstrated similar changes, that is, ST-elevation (median peak voltage gradient 150 muV, range 0-1,700) and T-wave changes in the sinus beat prior to ventricular ectopy. In addition, J-point elevation was demonstrated in several cases. In total, significant changes were demonstrated in 15 of the 18 patients studied (83%).
  
  
  CONCLUSIONS
  J-point elevation, ST-elevation, and T-wave changes documented in the last sinus beat prior to ventricular extrasystoles are in agreement with phase 2 reentry, suggesting that this may be the responsible mechanism for ventricular extrasystoles and ventricular tachycardia/fibrillation. The phenomenon has been demonstrated in only animal experiments to date.
authors.affiliation: Cardiology Department P, Gentofte University Hospital, Copenhagen, Denmark. pebt@heart.dk
authors.forename: Poul Erik
authors.initials: PE
authors.lastname: Bloch Thomsen
authors.forename: Rikke Moerch
authors.initials: RM
authors.lastname: Joergensen
authors.forename: Jørgen Kim
authors.initials: JK
authors.lastname: Kanters
authors.forename: Thomas Jon
authors.initials: TJ
authors.lastname: Jensen
authors.forename: Jens
authors.initials: J
authors.lastname: Haarbo
authors.forename: Arne
authors.initials: A
authors.lastname: Hagemann
authors.forename: Annette
authors.initials: A
authors.lastname: Vestergaard
authors.forename: Knud
authors.initials: K
authors.lastname: Saermark
mesh_terms: D000328:Adult; D000368:Aged; D002037:Bundle-Branch Block / Q000000981:diagnostic imaging / Q000503:physiopathology*; D017115:Catheter Ablation; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011859:Radiography; D013577:Syndrome; D013599:Systole / Q000502:physiology*; D017180:Tachycardia, Ventricular / Q000000981:diagnostic imaging / Q000503:physiopathology*; D014693:Ventricular Fibrillation / Q000000981:diagnostic imaging / Q000503:physiopathology*