title: Radiofrequency ablation guided by mechanical termination of idiopathic ventricular arrhythmias originating in the right ventricular outflow tract.
abstract: BACKGROUND
  Termination of ventricular tachycardia (VT) by mechanical pressure has been described for fascicular and postinfarction VT. Mechanical interruption of idiopathic ventricular arrhythmias (VT/premature ventricular complexes [PVCs]) arising in the right ventricular outflow tract (RVOT) has not been described in systematic fashion.
  
  
  METHODS
  Eighteen consecutive patients (13 females, age 49 +/- 13 years, ejection fraction 0.55 +/- 0.12) underwent mapping and ablation of RVOT VT or PVCs. In 7 patients, 9 distinct VTs (mean cycle length 440 +/- 127 ms), and in 11 patients, 11 distinct PVCs originating in the RVOT were targeted. Mechanical termination was considered present if a reproducibly inducible VT was no longer inducible or if frequent PVCs suddenly ceased with the mapping catheter at a particular location. Endocardial activation time, electrogram characteristics, and pace-mapping morphology were assessed at this location. Radiofrequency energy was delivered if mechanical termination was observed.
  
  
  RESULTS
  All targeted arrhythmias were successfully ablated. In 7 of 18 patients (39%), catheter manipulation terminated the arrhythmia with the mapping catheter located at a particular site. Local endocardial activation time was earlier at sites of mechanical termination (-31 +/- 7 ms) compared with effective sites without termination (-25 +/- 3 ms, P = 0.04). The 10-ms isochronal area was smaller in patients with mechanical interruption (0.35 +/- 0.2 cm(2)) than in patients without mechanical termination (1.33 +/- 0.9 cm(2), P = 0.01). At all sites susceptible to mechanical trauma, the pace map displayed a match with the targeted VT/PVC. All sites where mechanical termination of VT or PVCs occurred were effective ablation sites.
  
  
  CONCLUSIONS
  Mechanical suppression at the site of origin of idiopathic RVOT arrhythmias frequently occurs during the mapping procedure and is a reliable indicator of effective ablation sites. Mechanical termination of RVOT arrhythmias may be indicative of a more localized arrhythmogenic substrate.
authors: University of Michigan Health System, Ann Arbor, Michigan, USA.
authors: Michael
authors: M
authors: Kühne
authors: Jean-Francois
authors: JF
authors: Sarrazin
authors: Thomas
authors: T
authors: Crawford
authors: Matthew
authors: M
authors: Ebinger
authors: Eric
authors: E
authors: Good
authors: Aman
authors: A
authors: Chugh
authors: Krit
authors: K
authors: Jongnarangsin
authors: Frank
authors: F
authors: Pelosi
authors: Hakan
authors: H
authors: Oral
authors: Fred
authors: F
authors: Morady
authors: Frank M
authors: FM
authors: Bogun
mesh_terms: D018780:Body Surface Potential Mapping / Q000379:methods*; D017115:Catheter Ablation / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010173:Palpation / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017180:Tachycardia, Ventricular / Q000150:complications / Q000175:diagnosis* / Q000601:surgery*; D016896:Treatment Outcome; D014694:Ventricular Outflow Obstruction / Q000175:diagnosis* / Q000209:etiology / Q000601:surgery*