title: Cryoablation of focal tachycardia originating from the right atrial free wall during upstream phrenic pacing to avoid phrenic nerve injury.
abstract: BACKGROUND
  Recognition of the potential for phrenic nerve injury (PNI) often prompts less aggressive attempts at catheter ablation of multiple forms of tachycardia or abandoning ablation altogether. Some novel techniques to avoid PNI during catheter ablation have been described.
  
  
  METHODS
  Five patients (age: 13-57 years, three females) with ectopic atrial tachycardia originating from the right atrial free wall (RAFW) near the phrenic nerve underwent electrophysiology study with three-dimensional mapping and endocardial cryoablation. Upstream phrenic pacing was performed after cryoadherence was achieved, and cryoablation of ectopic foci was performed during close observation for occurrence of PNI and tachycardia elimination.
  
  
  RESULTS
  Cryoablation acutely eliminated five of six atrial tachycardias originating close to the phrenic nerve. Transient PNI during cryothermy occurred in two patients, and resolved within 3 minutes. Patients were observed overnight on telemetry, with no early recurrences of targeted atrial tachycardias and no evidence of PNI. At last follow-up of 1-39 months, four patients were arrhythmia free on no medications.
  
  
  CONCLUSIONS
  Catheter cryoablation during simultaneous upstream phrenic nerve pacing can lead to safe and effective elimination of focal atrial tachycardias originating from the RAFW close to the phrenic nerve.
authors.affiliation: Division of Pediatric Cardiology, Department of Pediatrics, University of Louisville School of Medicine, Louisville, Kentucky.
authors.forename: Christopher
authors.initials: C
authors.lastname: Johnsrude
mesh_terms: D000293:Adolescent; D000328:Adult; D017115:Catheter Ablation / Q000379:methods*; D003452:Cryosurgery; D005260:Female; D006325:Heart Atria; D006801:Humans; D007431:Intraoperative Complications / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D010791:Phrenic Nerve / Q000293:injuries*; D012189:Retrospective Studies; D013612:Tachycardia, Ectopic Atrial / Q000601:surgery*; D055815:Young Adult
keywords: atrial tachycardia; catheter ablation; phrenic nerve