An area showing slow potentials is present at the perinodal region in humans. In patients with AVNRT, application of radiofrequency energy renders tachycardia noninducible through the preferential modification of the anterograde slow pathway. With present clinical methods, the exact origin and significance of these physiological potentials cannot be specified.

The present study provides evidence that the mechanism of successful AFI ablation targeting the IVC-TA isthmus is local bidirectional conduction block. This change can be used as a new and complementary electrophysiological end point for the procedure. AFI recurrences are associated with failure to achieve a permanent block.

The observations indicate that AF may be linked to "focal" mechanisms that can be treated by RF catheter ablation.

Catheter Ablation of AF. introduction: Catheter ablation of a case of incessant atrial fibriliation was attempted using linear right atriai lesions created by sequential applications of radiofrequency energy. Methods and Results:A 46-year-o!d patient had incessant episodes of atrial fibrillation. He had previously undergone successful radiofrequency catheter ablation of a common atrial flutter. Antiarrhythmic drugs including amiodarone and various drug combinations were ineffective. A 7-French specially designed 14-polar catheter with interelectrode distance of 3 mm was used to create linear lesions in the right atrium. Each electrode was 4 mm in length and able to transmit radiofrequency energy. Three linear lesions, two longitudinal and one transverse that connected the two longitudinal lesions, were created using 30 radiofrequency applications of 10 to 40 W. The final application interrupted an atrial fibrillation that had been persistent for 55 minutes. No sustained atrial fibrillation was inducible despite repeated pacing maneuvers. Tbere was no complication. In short-term follow-up of 3 months, the patient has been free of arrhythmias without antiarrhythmic medication.Conclusion: Successful catheter ablation of human atrial fibrillation is feasible using linear atrial lesions created by radiofrequency energy delivery. Furtber studies are mandatory to ascertain the efficacy and safety of this procedure, as well as to assess different catheter techniques.