Success rate of catheter ablation in atrial flutter: comparison of a 4- or 5-mm tip electrode catheter with an 8-mm tip electrode catheter.

BACKGROUND: Radio frequency (RF) energy is capable of interrupting the reentrant circuit of atrial flutter and curing the arrhythmia. The development of 8-mm tip catheter provides more tissue damage and has offered the promise of improved success. The purpose of our study was to determine if the acute and long-term success with the 8-mm tips were superior to the 4- or 5-mm tips.
MATERIALS AND METHODS: The outcomes of the first 20 patients in whom an 8-mm tip catheter was used were compared with the previous 20 patients in whom a 4-or 5-mm tip catheter was used. Procedural (acute) ablation success was defined by creation of bi-directional isthmus block. Long-term success was defined as the prevention of clinically evident atrial flutter (AFl) as determined by the absence of symptoms or maintenance of sinus rhythm on electrocardiogram, six months to one year after the procedure.
RESULTS: Compared to the 4- or 5-mm tip, the 8-mm catheter tip was associated with a reduced ablation duration {22.3 +/- 16 versus 11.5 +/- 5 min (p = 0.0078)}, a lower mean number of ablations {13.5 +/- 9.9 versus 6.8 +/- 2.9 (p = 0.0065)} and a reduced procedure time {1.8 +/- 0.7 versus 1.1 +/- 0.5 h (p = 0.0032)}. Acute success was 95% in the 4- or 5-mm group versus 80% in the 8-mm group (p = NS), but long-term success was higher in the 8-mm group than the 4- or 5-mm group (87.5 versus 63.2%, p = 0.0436).
CONCLUSIONS: Eight-millimeter tip catheters for AFl shorten procedure time, reduce the duration and number of ablations and accomplish bi-directional block when compared with smaller tipped catheters. The long-term success rate is better with the 8-mm tips and should be the preferred catheter for RF ablation of AFl.