RADIOFREQUENCY CATHETER ABLATION IN UNUSUAL MECHANISMS OF ATRIAL-FIBRILLATION - REPORT OF 3 CASES

Introduction: The purpose of this study was to test the feasibility of radiofrequency (RF) catheter ablation of localized mechanisms of atrial fibrillation (AF). Methods and Results: Three patients underwent RF catheter ablation for drug-resistant atrial arrhythmias. The first two patients had either incessant atrial tachycardia or AF. In the first patient, the ECG pattern of AF was mimicked by a very rapid atrial focus, whereas in the second patient, AF was due to true degeneration of the atrial activity triggered by atrial tachycardia. In both patients, the ablation of atrial focus led to the clinical disappearance of AF. The third patient had frequent episodes of AF, which lasted several days or weeks, and two documented episodes of atrial flutter. Mapping during AF showed an irregular atrial rhythm in the atrial septum, particularly in the region surrounding the coronary sinus, whereas the entire lateral right atrial free wail exhibited a constantly organized rhythm. RF energy was applied between the tricuspid ring and both the inferior vena cava and the coronary sinus, resulting in inability to reinduce atrial flutter or sustained AF. A 6-month follow-up in this patient showed the disappearance of prolonged episodes of AF. Conclusion: The observations indicate that AF may be linked to ''focal'' mechanisms that can be treated by RF catheter ablation.