Radiofrequency ablation of atrial flutter: Predictive factors of primary success and medium term results

Ninety-one consecutive patients under-went radiofrequency ablation of chron ic or paroxysmal atrial flutter. The average age of the patients was 66. Th ere was a previous history of atrial fibrillation in 38% of cases and of ca rdiac surgery in 14.3% of cases. The primary success rate was 79% (92% in cases of common flutter). The pred ictive factors of success were the type of flutter (p < 0.001), left ventri cular (p < 0.01) and left atrial dimensions (p < 0.01) at echocardiography. The length of the cavo-tricuspid isthmus measured by echocardiography had no influence on the initial result but, in primary success, did affect the parameters of the procedure (duration and number of applications of radiofr equency energy). After an average of 11 +/- 2 months, sinus rhythm was maintained if 67% of patients. There were recurrences of flutter in 27.5% of cases and of atrial fibrillation in 5.5% of cases : 85% of these episodes occurred during the first six months after ablation. A second procedure was carried out in 12 p atients for recurrence of flutter (92% primary success rate). After an aver age follow-up of 8.4 months, 4 patients had a recurrence and required a thi rd procedure (100% success rate). In cases of failure of ablation, the rhyt hm was converted by a shock or atrial pacing : 47.3% of these patients rema ined in sinus rhythm with antiarrhythmic therapy with a 12 month follow-up. Radiofrequency ablation of atrial flutter is, therefore, a safe method, the difficulty of which is mainly related to anatomical factors : the medium-t erm results are better than those of other therapeutic methods.