RADIOFREQUENCY ABLATION OF ATRIAL-FLUTTER AND ATRIAL TACHYCARDIAS IN PATIENTS WITH PERMANENT INDWELLING CATHETERS

The presence of chronic indwelling leads in the area targeted for RF a blation may pose a technical challenge and reduce the chance of succes s of the ablation. In addition, application of lesions in close proxim ity to pacemaker leads or other permanent catheters could affect their function. Fourteen patients referred for RF ablation of atrial flutte r/fibrillation and atrial tachycardia, who had a permanent dual chambe r pacemaker (10 patients), ICD (1 patients), or both (3 patients) were studied to assess the safety, efficacy, and effects of the ablative p rocedure on device function. Lead impedance, R and P wave amplitude, a nd pacing threshold of the defibrillator and pacemaker were measured b efore and after ablation. The procedure was successful in all patients . In one patient who underwent both atrial flutter and atrial fibrilla tion ablation, the atrial pacing threshold increased from 1.0 preablat ion to 2.0 V postablation. No P wave was detectable after ablation. In another patient, the P wave amplitude went from 4.0 to 2.0 V postabla tion. In both patients the device converted to the power reset mode. N o changes were observed in the remaining patients. Postablation defibr illator testing showed no malfunction. Follow-up reinterrogation of th e devices revealed no alterations. In conclusion: (1) RF ablation of a trial flutter and/or tachycardia is feasible even in patients with mul tiple chronic atrial and ventricular indwelling catheters; and (2) RF applications in close proximity of defibrillator and pacing catheters does not appear to alter their function unless lesions are produced in the area surrounding the distal pacing electrode.