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°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.Conclusion: 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)