title: Echocardiographically guided left atrial ablation: characterization of a new technique.
abstract: BACKGROUND
  Several techniques for percutaneous catheter-based radiofrequency ablation of left atrial myocardium have been described. Each is potentially limited by anatomic inaccuracy, radiation requirement, cardiac/extracardiac collateral damage, proarrhythmia, lesion impermanence, or unclear procedural endpoint.
  
  
  OBJECTIVE
  The purpose of this study was to describe a new technique that may address some of these limitations.
  
  
  METHODS
  In 200 consecutive patients with atrial fibrillation (AF), complete ablative encircling of right and left pulmonary venous vestibules was performed using radiofrequency energy applied via a standard ablation electrode. Lesions were guided by a collaborative nonfluoroscopic imaging strategy involving intra-left atrial echocardiography and CARTO. A discrete procedural endpoint was sought: complete electrical isolation of all myocardium subtended by the encircling lesions.
  
  
  RESULTS
  After a procedure in which the total fluoroscopy time averaged 6 minutes, isolation was achieved on the left and right sides in 198 and 199 patients, respectively. In addition to the vestibule-encircling lesions, isolation required one or more additional focal lesions within the subtended myocardial territory in the majority of left vestibules and in a minority of right vestibules. Significant procedural morbidity was observed, including cerebroembolism resulting in death and mesenteric embolism resulting in hemicolectomy. Procedural success, defined at 2 years after the initial procedure and requiring no interim procedure, antiarrhythmic drug therapy, or apparent arrhythmia burden, was observed in a significantly greater proportion of patients with a paroxysmal (87%) than persistent AF (60%) syndrome. Only a small proportion of patients with recurrent AF had recurrence of conduction in previously isolated zones.
  
  
  CONCLUSIONS
  This technique may have advantages over those previously reported, including improved anatomic accuracy, improved lesion safety and efficacy, and diminished radiation exposure.
authors.affiliation: Cardiovascular Institute, University of Pittsburgh, Pennsylvania 15213, USA. schwartzmand@upmc.edu
authors.forename: David
authors.initials: D
authors.lastname: Schwartzman
authors.forename: John
authors.initials: J
authors.lastname: Nosbisch
authors.forename: Debra
authors.initials: D
authors.lastname: Housel
mesh_terms: D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery*; D016275:Atrial Function; D017115:Catheter Ablation / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D004452:Echocardiography; D004567:Electrodes, Implanted; D005260:Female; D005500:Follow-Up Studies; D006325:Heart Atria / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D006801:Humans; D007430:Intraoperative Care; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000473:pathology; D011182:Postoperative Care; D011667:Pulmonary Veins / Q000601:surgery; D012008:Recurrence; D012107:Research Design; D016896:Treatment Outcome