title: Clinical value of noninducibility by high-dose isoproterenol versus rapid atrial pacing after catheter ablation of paroxysmal atrial fibrillation.
abstract: BACKGROUND
  AF can be induced by RAP or ISO in >85% of patients with PAF.
  
  
  METHODS
  ISO was administered in escalating doses of 5, 10, 15, and 20 microg/min in 112 patients (age = 56 +/- 13 years) with PAF before radiofrequency catheter ablation. AF was inducible in 97 of 112 patients (87%) at a mean dose of 15 +/- 5 microg/min. RAP induced AF in the remaining 14 of 15 patients. Antral pulmonary vein (PV) isolation (APVI) was followed by ablation of complex fractionated atrial electrograms (CFAEs) as necessary to terminate AF and render AF noninducible in response to ISO.
  
  
  RESULTS
  AF terminated during APVI in 72 of 111 patients (65%) and after APVI plus ablation of CFAEs in 11 of 111 patients (10%). In the remaining 28 patients (25%), sinus rhythm was restored by transthoracic cardioversion. RAP was performed in the last 61 consecutive patients who were rendered noninducible by ISO. RAP initiated AF in 20 of 61 patients (33%) and atrial flutter in 6 patients (10%). No additional ablation was performed if AF was induced with RAP; however, atrial flutter was targeted. At 12 +/- 5 months, 63/75 patients (84%) who were noninducible by ISO and 2 of 8 (25%) who still were reinducible by ISO were free from recurrent AF after a single ablation procedure without antiarrhythmic drugs (P = 0.001). AF recurred in 20 of 36 patients (56%) who required cardioversion for persistent AF after ablation (P < 0.001). Among the 61 patients who also underwent RAP, 12 of 20 (60%) who were, and 31 of 41 (76%) who were not inducible by RAP were free from recurrent AF (P = 0.21). The accuracy of noninducibility as a predictor of clinical outcome was 83% with ISO and 64% by RAP (P = 0.03).
  
  
  CONCLUSIONS
  The response to isoproterenol after catheter ablation of PAF more accurately predicts clinical outcome than the response to RAP.
authors.affiliation: Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Crawford
authors.forename: Aman
authors.initials: A
authors.lastname: Chugh
authors.forename: Eric
authors.initials: E
authors.lastname: Good
authors.forename: Kentaro
authors.initials: K
authors.lastname: Yoshida
authors.forename: Krit
authors.initials: K
authors.lastname: Jongnarangsin
authors.forename: Matthew
authors.initials: M
authors.lastname: Ebinger
authors.forename: Frank
authors.initials: F
authors.lastname: Pelosi
authors.forename: Frank
authors.initials: F
authors.lastname: Bogun
authors.forename: Fred
authors.initials: F
authors.lastname: Morady
authors.forename: Hakan
authors.initials: H
authors.lastname: Oral
mesh_terms: D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000601:surgery*; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D002316:Cardiotonic Agents / Q000008:administration & dosage; D017115:Catheter Ablation; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007545:Isoproterenol / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016896:Treatment Outcome
chemical_list: D002316:Cardiotonic Agents; D007545:Isoproterenol