title: Radiofrequency catheter ablation of inappropriate sinus tachycardia guided by activation mapping.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the value of activation mapping for radiofrequency modification of the sinus node and the long-term success rate of the procedure in a series of patients with inappropriate sinus tachycardia.
  
  
  BACKGROUND
  The results of radiofrequency ablation of inappropriate sinus tachycardia have been reported in only a small number of patients.
  
  
  METHODS
  The subjects of this study were 29 consecutive drug-refractory patients who underwent catheter ablation of inappropriate sinus tachycardia. Target sites were selected by activation mapping during sinus tachycardia.
  
  
  RESULTS
  The ablation procedure was successful acutely in reducing the baseline sinus rate to <90/min and the sinus rate during isoproterenol infusion by >20% in 22 of 29 patients (76%). In 13 of 22 patients (59%) with a successful acute outcome, successive applications of radiofrequency energy at the site of earliest endocardial activation resulted in a cranial-caudal migration of earliest endocardial activation from the high lateral right atrium, along with a step-wise reduction in heart rate. In the other nine patients (41%) with a successful acute outcome, the reduction in sinus rate occurred abruptly, unaccompanied by migration of the site of earliest activation. Symptoms due to inappropriate sinus tachycardia recurred at a mean of 4.4+/-; 3 months after the ablation procedure in 6 of 22 patients (27%). After additional procedures in three patients, symptoms of inappropriate sinus tachycardia ultimately were successfully eliminated over the long-term in 19 of 29 patients (66%).
  
  
  CONCLUSIONS
  In conclusion, radiofrequency ablation is at best only modestly effective for managing patients with inappropriate sinus tachycardia. The two different responses of heart rate to radiofrequency ablation may reflect differences in the number and/or multicentricity of subsidiary sites of impulse generation within the sinus node and/or atrium in patients with inappropriate sinus tachycardia.
authors.affiliation: Department of Internal Medicine, University of Michigan, Ann Arbor 48109-0022, USA.
authors.forename: K C
authors.initials: KC
authors.lastname: Man
authors.forename: B
authors.initials: B
authors.lastname: Knight
authors.forename: H F
authors.initials: HF
authors.lastname: Tse
authors.forename: F
authors.initials: F
authors.lastname: Pelosi
authors.forename: G F
authors.initials: GF
authors.lastname: Michaud
authors.forename: M
authors.initials: M
authors.lastname: Flemming
authors.forename: S A
authors.initials: SA
authors.lastname: Strickberger
authors.forename: F
authors.initials: F
authors.lastname: Morady
mesh_terms: D000200:Action Potentials; D000328:Adult; D000368:Aged; D018780:Body Surface Potential Mapping / Q000379:methods*; D017115:Catheter Ablation; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D012086:Reoperation; D013616:Tachycardia, Sinus / Q000503:physiopathology / Q000601:surgery*; D016896:Treatment Outcome