title: Induction of atrioventricular node reentrant tachycardia with adenosine: differential effect of adenosine on fast and slow atrioventricular node pathways.
abstract: OBJECTIVE
  This study sought to evaluate the sensitivity of fast and slow atrioventricular (AV) node pathways to incremental doses of adenosine in patients with typical AV node reentrant tachycardia.
  
  
  BACKGROUND
  Although adenosine is known to depress conduction through the AV node, the relative sensitivity to adenosine of the anterograde fast and slow pathways in patients with dual AV node pathways and typical AV node reentrant tachycardia has not previously been studied.
  
  
  METHODS
  Sixteen patients with dual AV node physiology and typical AV node reentrant tachycardia and 10 control patients were given incremental doses of adenosine during atrial pacing.
  
  
  RESULTS
  In 14 of 16 patients with dual-AV node physiology, administration of small doses of adenosine during atrial pacing led consistently to transient block of impulse conduction in the fast pathway before block in the slow pathway, resulting in abrupt prolongation of the AH interval with continued 1:1 AV conduction. The mean (+/- SD) doses of adenosine required to cause conduction block in the fast and slow pathways were 2.7 +/- 3.0 and 7.2 +/- 4.7 mg, respectively (p = 0.004). In 9 of 16 patients, administration of low dose adenosine led to initiation of AV node reentrant tachycardia. The control patients showed no abrupt increases in AH interval with administration of adenosine during atrial pacing.
  
  
  CONCLUSIONS
  In most patients with dual AV node pathways and typical AV node reentrant tachycardia, the fast pathway is more sensitive than the slow pathway to the effects of adenosine.
authors.affiliation: Department of Medicine, University of Florida, Gainesville 32610, USA. curtis.medcs0@shands.ufl.edu
authors.forename: A B
authors.initials: AB
authors.lastname: Curtis
authors.forename: L
authors.initials: L
authors.lastname: Belardinelli
authors.forename: D A
authors.initials: DA
authors.lastname: Woodard
authors.forename: C S
authors.initials: CS
authors.lastname: Brown
authors.forename: J B
authors.initials: JB
authors.lastname: Conti
mesh_terms: D000241:Adenosine / Q000008:administration & dosage; D001283:Atrioventricular Node / Q000187:drug effects* / Q000502:physiology; D006328:Cardiac Catheterization; D002304:Cardiac Pacing, Artificial; D016022:Case-Control Studies; D017115:Catheter Ablation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000139:chemically induced* / Q000503:physiopathology / Q000601:surgery
chemical_list: D000241:Adenosine