title: Catheter mounted coaxially moveable ablation electrode for the creation of linear transmural endocardial lesions.
abstract: BACKGROUND
  Use of a novel ablation catheter for the creation of linear transmural endocardial lesions, which uses a coaxially moving ablation electrode mounted on the terminal portion of a catheter shaft and able to move axially for a distance of up to 4 cm, is reported.
  
  
  RESULTS
  The coaxially moving ablation electrode is moved by a sliding mechanism in the catheter handle. The distal portion of the catheter shaft is steerable. Bipolar or unipolar electrograms can be recorded from electrodes on the catheter tip and the coaxially moving ablation. Radiofrequency (RF) current is delivered to the coaxially moving ablation electrode with thermocouple temperature control. This ablation catheter was evaluated in five (30 to 65 kg) anesthetized pigs and introduced via the venous/arterial systems into the right and left atrium (1 lesion) (using the retrograde aortic approach). The catheter was maneuvered to bring the slide range into apposition with atrial endocardium. The coaxially moving ablation electrode was deployed to the terminal portion of the catheter's slide range and then withdrawn in 2-mm steps. RF current was delivered to the coaxially moving ablation electrode at each point (maximum temperature 70 degrees C). Postmortem examination of eight endocardial linear lesions (2.2 to 4.1 cm length) was made 1 to 3 hours after creation. Histopathologic examination confirmed transmural myocyte necrosis along the length of the lesion, that included the trabeculated right atrium.
  
  
  CONCLUSIONS
  We conclude that a catheter using a moveable electrode creates continuous linear transmural lesions and could find clinical application in the therapy of a variety of reentry tachycardia mechanisms.
authors.affiliation: Wessex Cardiothoracic Center, Southampton University Hospital, United Kingdom. JMM@cardiology.co.uk
authors.forename: J M
authors.initials: JM
authors.lastname: Morgan
authors.forename: P R
authors.initials: PR
authors.lastname: Roberts
authors.forename: S
authors.initials: S
authors.lastname: Allen
authors.forename: P J
authors.initials: PJ
authors.lastname: Gallagher
authors.forename: C
authors.initials: C
authors.lastname: Gibson
authors.forename: A D
authors.initials: AD
authors.lastname: Cunningham
mesh_terms: D000818:Animals; D006328:Cardiac Catheterization; D017115:Catheter Ablation / Q000295:instrumentation*; D004195:Disease Models, Animal; D004562:Electrocardiography; D004566:Electrodes; D004699:Endocardium / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D005260:Female; D006325:Heart Atria / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D006329:Heart Conduction System / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D009336:Necrosis; D013552:Swine