title: Bipolar radiofrequency catheter ablation for refractory ventricular outflow tract arrhythmias.
abstract: BACKGROUND
  Standard unipolar radiofrequency ablation (RFA) is typically successful in eliminating premature ventricular contractions (PVCs) originating from the ventricular outflow tract region. In a minority of cases, this approach may be ineffective. We report 4 cases where bipolar RFA was attempted after failed unipolar RFA.
  
  
  METHODS
  From a total of 73 consecutive PVC ablations, 4 patients underwent bipolar RFA after failed unipolar ablation. Three-dimensional electroanatomic activation mapping of the right and left ventricular outflow (RVOT and LVOT), coronary sinus, and aortic root was performed.
  
  
  RESULTS
  Mean age was 53 ± 22 years, 3 male. The mean 24-hour PVC burden in these patients was 33,107 ± 8,712. In 3 of 4 patients, the RVOT activation was earlier than the left side. The earliest activation on the left was in the right coronary cusp in 2 patients and left coronary cusp in 2. Unipolar RFA delivered sequentially at the site of earliest RVOT and then earliest aortic cusp sites failed to eradicate the PVCs in all 4 patients. Subsequently, bipolar RFA was applied between irrigated catheters placed at the earliest RVOT and aortic root sites. This approach eliminated PVCs in 3 of 4 (75%) cases. At a median follow-up of 4 months, those with successful bipolar RFA had no recurrence of clinical PVCs.
  
  
  CONCLUSIONS
  This report demonstrates the potential utility of bipolar RFA in patients with outflow tract PVCs that fail unipolar RFA.
authors.affiliation: Helmsley Electrophysiology Center, Mount Sinai School of Medicine, New York City, New York, USA; Cardiology Department, Monash University Eastern Health, Victoria, Australia; Department of Cardiology, Austin Hospital, Victoria, Australia.
authors.forename: Andrew W
authors.initials: AW
authors.lastname: Teh
authors.forename: Vivek Y
authors.initials: VY
authors.lastname: Reddy
authors.forename: Jacob S
authors.initials: JS
authors.lastname: Koruth
authors.forename: Marc A
authors.initials: MA
authors.lastname: Miller
authors.forename: Subbarao
authors.initials: S
authors.lastname: Choudry
authors.forename: Andre
authors.initials: A
authors.lastname: D'Avila
authors.forename: Srinivas R
authors.initials: SR
authors.lastname: Dukkipati
mesh_terms: D000328:Adult; D000369:Aged, 80 and over; D018780:Body Surface Potential Mapping; D017115:Catheter Ablation / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome; D014694:Ventricular Outflow Obstruction / Q000150:complications / Q000175:diagnosis* / Q000601:surgery*; D018879:Ventricular Premature Complexes / Q000150:complications / Q000175:diagnosis* / Q000601:surgery*
keywords: catheter ablation; electroanatomic mapping; ventricular tachycardia