Linear ablation with duty-cycled radiofrequency energy at the cavotricuspid isthmus.
BACKGROUND
Multielectrode catheters using duty-cycled radiofrequency (RF) have been developed to treat atrial fibrillation (AF). Many of these patients also have atrial flutter. Therefore, a linear multielectrode has been developed using the same RF energy.


OBJECTIVE
The concept and acute results of linear ablation using duty-cycled RF were tested in the cavotricuspid isthmus (CTI).


METHODS
The CTI was targeted in 75 patients, in 68 (90%) among them as an adjunct to AF ablation with the same technology. A linear electrode catheter with a 4-mm tip and five 2-mm ring electrodes was connected to a generator titrating duty-cycled RF at 20-45 W up to a target temperature of 70 degrees C in 1:1 unipolar/bipolar mode.


RESULTS
During a mean procedure time of 20 +/- 12 minutes, complete CTI block was achieved by 4 +/- 3 applications of duty-cycled RF in 69 (92%) patients. No more than three RF applications were necessary in 60% of patients. During the initial learning curve, standard RF had to be used in five (7%) patients. Complete block was not achieved in one patient with frequent episodes of AF. Char was observed in five (7%) patients with poor electrode cooling; consequently, the temperature ramp-up was slowed and manually turned off in the event of low-power delivery. Two groin hematomas occurred; otherwise, no clinical complications were observed.


CONCLUSIONS
Multielectrode catheters delivering duty-cycled RF can effectively ablate the CTI with few RF applications with promising acute results. Further modifications are necessary to improve catheter steering and prevent char formation. (PACE 2010; 444-450).
Boll
Stefanie
S
Cardiovascular Center, Clinic im Park, Zurich, Switzerland.
Dang
Lam
L
Scharf
Christoph
C
D000328:Adult; D000368:Aged; D001282:Atrial Flutter / Q000601:surgery*; D017115:Catheter Ablation / Q000009:adverse effects / Q000379:methods*; D004566:Electrodes; D005260:Female; D006119:Groin; D006329:Heart Conduction System / Q000601:surgery; D006406:Hematoma / Q000209:etiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome; D014261:Tricuspid Valve / Q000601:surgery*; D014682:Vena Cava, Inferior / Q000601:surgery*; D055815:Young Adult