RADIOFREQUENCY ABLATION OF ATRIAL-FLUTTER - LONG-TERM RESULTS AFTER 8YEARS OF EXPERIENCE

Objective. Since the 1990's radiofrequency ablation radiofrequency abl ation of atrial nutter has evolved in its methods and results. We have reviewed the long term outcome in 62 patients with typical (common) o r reversed (clockwise) nutter undergoing radiofrequency ablation betwe en 1990 and 1997. Patients and methods. Fifty men and 12 women, aged 2 2-78 years (57 +/- 12) with nutter recurring after cardioversion and a ntiarrhythmic drugs make this series. Flutter was typical in 59 cases and reversed in 3. There was no heart disease in 14, bronchopulmonary disease in 10, coronary disease in 9, cardiomyopathies in 6 and other processes in the remainder. In 5 cases with previous surgery for atria l or ventricular septal defect, Ebstein's anomaly or myxoma, we treate d also a macroreentrant tachycardia around the atriotomy in the right atrium. Radiofrequency ablation was directed to the inferior vena cava -tricuspid isthmus in typical and reversed flutter, and to the isthmus between the inferior end of the atriotomy and the inferior vena cava, in the lateral right atrium, in the atriotomy tachycardias. We subdiv ided our patients in Group 1 (24 patients), treated until the end of 1 994, and Group 2 (38 patients) treated since 1995 using specially desi gned catheters and trying to produce isthmus block as the endpoint of the procedure. Results. Radiofrequency ablation interrupted flutter in 61 of 62 cases (98.4%), and the atriotomy tachycardia in all 5. The n umber of application in Group 1 was 18.6 +/- 10.1 vs 12 +/- 10 in Grou p 2 (p < 0.05). Follow-up was 40 +/- 24 months in Group 1 vs 16 +/- 9. 5 in Group 2. Flutter recurred in 58% of Group 1 and 13% of Group 2 pa tients (p < 0.001), usually 1-3 months after radiofrequency ablation a nd they were successfuly treated by new radiofrequency ablation with a small number of applications. There was no recurrence of atriotomy ta chycardia. Atrial fibrillation occurred in 14 patients (23%) (11 parox ysmal, 3 persistent), with equal incidence in both groups. At the end of follow-up 85% of the patients were in sinus rhythm, although 6 need ed pacemakers for sinus node dysfunction (3) or AV ablation (3). Antia rrhythmic drugs were used by 46% of patients in Group I and 26% in Gro up 2 (p = NS) for atrial arrhythmias or recurrent flutter. Conclusions . Radiofrequency ablation is an effective treatment for flutter and ma croreentrant atriotomy tachycardia. Progress in methods have improved results significantly. Atrial fibrillation can still be a problem in 2 0-25% of the patients after flutter control.