title: Change in the retrograde atrial activation sequence following radiofrequency modification of the atrioventricular node: implications for the electrophysiologic circuit of a variant of atrioventricular nodal reentrant tachycardia.
abstract: BACKGROUND
  Despite the great success in treating AV nodal reentrant tachycardia (AVNRT) with radiofrequency modification of the AV node, the dimensions of the electrophysiologic circuit of this arrhythmia remain unclear, and simple models fail to explain all tachycardia-related phenomena.
  
  
  RESULTS
  We describe three unusual cases of supraventricular tachycardia (SVT). In all three cases, retrograde atrial activation during ventricular pacing or during SVT manifested local left atrial electrograms recorded from the coronary sinus preceding the septal atrial electrograms (eccentric activation), with earliest atrial activity at the lateral or posterolateral mitral annulus. Electrophysiologic maneuvers and observations were consistent with AVNRT as the mechanism in each case. In all cases, radiofrequency modification of the AV node eliminated inducible SVT and abolished dual pathway AV nodal physiology. The retrograde atrial activation sequence during ventricular pacing changed after ablation in each case, with septal atrial electrograms preceding left atrial electrograms recorded from the coronary sinus (concentric activation).
  
  
  CONCLUSIONS
  The observations in these cases cannot be explained by the traditional model of slow, fast, and intermediate AV nodal pathways. A model incorporating a circuit close to the AV node with left atrial and coronary sinus connections is proposed.
authors.affiliation: Division of Cardiology, Presbyterian Hospital, Columbia University, New York, New York, USA.
authors.forename: José
authors.initials: J
authors.lastname: Dizon
authors.forename: James
authors.initials: J
authors.lastname: Reiffel
authors.forename: John
authors.initials: J
authors.lastname: Kassotis
authors.forename: Ian
authors.initials: I
authors.lastname: Woollett
authors.forename: Hasan
authors.initials: H
authors.lastname: Garan
mesh_terms: D016275:Atrial Function / Q000502:physiology*; D001283:Atrioventricular Node / Q000503:physiopathology* / Q000601:surgery*; D017115:Catheter Ablation; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006325:Heart Atria / Q000503:physiopathology / Q000601:surgery; D006801:Humans; D008875:Middle Aged; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000503:physiopathology / Q000601:surgery