RADIOFREQUENCY CATHETER ABLATION FOR PAROXYSMAL SUPRAVENTRICULAR TACHYCARDIA - A REPORT OF 135 PROCEDURES

Background. Paroxysmal Supraventricular Tachycardia (PSVT) is a common condition which until recently has been treated with anti-arrhythmic drugs or surgery. Radiofrequency (RF) catheter ablation is a new mode of treatment which provides a cure of this condition. Aims: To present our early experience of RF catheter ablation for PSVT. Methods: One h undred and thirty-five procedures were performed in 117 patients. The diagnostic study and therapeutic catheter ablation were performed as a combined electrophysiological procedure in 74 patients (63%). In 58 p atients (50%), PSVT was due to Atrio-ventricular junctional (nodal) re -entrant tachycardia (AVJRT). Twenty-five of the 58 patients underwent a fast pathway ablation while 33 had ablation of their slow pathway. The mean number of radiofrequency pulses delivered was ten for a mean duration of 25 seconds. Radiofrequency ablation of accessory pathways was attempted in 58 patients; pathways were left-sided in 29 patients, postero-septal in 21, midseptal in five, Mahaim connection in two, an tero-septal in one and right free wall in one patient. One patient wit h incessant automatic atrial tachycardia also underwent a successful R F ablation. Results: Using RF ablation cure of PSVT was achieved in 90 % of patients. Cure of AVJRT was achieved in 95% (55/58) of patients u sing either fast or slow pathway ablation. Only one patient required p ermanent pacemaker implantation for Mobitz type I AV block following f ast pathway ablation. The overall success rate for ablation of accesso ry pathways was 85%. There is an operator learning curve for this proc edure suggested by the fact that the success rate for accessory pathwa y ablation at first attempt was 63% in the first 29 patients and 93% i n the remaining 29. There was no significant morbidity or mortality du ring or after the procedure. In a mean follow-up of nine months in the patients with successful ablation only two patients with AVJRT had a recurrence of documented PSVT. Both these patients had successful repe at RF ablation. Catheter ablation using radiofrequency energy is an ef fective and safe therapeutic option for patients with symptomatic PSVT .