title: Feasibility of the transseptal approach for fast and unstable left ventricular tachycardia mapping and ablation with a non-contact mapping system.
abstract: BACKGROUND
  Radiofrequency ablation of fast and unstable left ventricular tachycardia (VT) usually requires non-contact mapping. The procedure is usually performed by a retrograde-transaortic route, requiring a double femoral artery puncture, for the 9F multielectrode catheter and the 7F ablation catheter which are advanced through the aorta and aortic valve into the left ventricle (LV). Reported limitations of the procedure are due to the stiffness of the balloon catheter, particularly in patients with tortuous peripheral arteries, atherosclerotic aorta, or with aortic stenosis. The aim of our study was to test the feasibility and assess the safety of a transseptal approach for left VT non-contact mapping and ablation.
  
  
  METHODS
  Ten patients with multiple cardiac defibrillator shocks because of fast and unstable VT were selected for non-contact mapping and ablation. After a double transseptal puncture the multielectrode catheter (Ensite Array, St. Jude Medical) was advanced through a standard 10F introducer to a stable position in the LV apex over a 260 cm length 0.035 J-tip guidewire. The ablation catheter (Celsius Thermo-cool, Biosense Webster) was then inserted through the second 8F introducer. Twenty-five monomorphic sustained ventricular tachycardia were induced and ablated at the level of the diastolic pathway or exit point revealed by unipolar isopotential mapping. The total procedural and fluoroscopy times were 209 +/- 32 min and 28.5 +/- 9.27 min, respectively, which were comparable to those described with the traditional retrograde-transaortic approach. No major complication related with the transseptal approach were reported.
  
  
  CONCLUSIONS
  A transseptal approach can be a feasible and effective alternative approach for mapping and ablation of fast and unstable left VT with a non-contact mapping system.
authors.affiliation: S. Anna University Hospital, Corso Giovecca 203, 44100 Ferrara, Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Pratola
authors.forename: Elisa
authors.initials: E
authors.lastname: Baldo
authors.forename: Pasquale
authors.initials: P
authors.lastname: Notarstefano
authors.forename: Toselli
authors.initials: T
authors.lastname: Tiziano
authors.forename: Roberto
authors.initials: R
authors.lastname: Ferrari
mesh_terms: D000368:Aged; D018780:Body Surface Potential Mapping / Q000379:methods*; D009202:Cardiomyopathies / Q000628:therapy; D017115:Catheter Ablation / Q000379:methods*; D017023:Coronary Angiography; D022062:Electrophysiologic Techniques, Cardiac / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012815:Signal Processing, Computer-Assisted; D017180:Tachycardia, Ventricular / Q000175:diagnosis* / Q000628:therapy*