[Radiofrequency ablation of the slow nodal pathway in cases of paroxysmal nodal reentry tachycardia]. / Ablación por radiofrecuencia de la vía lenta nodal en caso de taquicardia por reentrada nodal paroxística.

INTRODUCTION: We describe our experience in the treatment of supraventricular tachycardia due to atrioventricular nodal reentry by radiofrequency catheter ablation of the slow pathway. PATIENTS AND METHODS: Thirty-four patients (mean age 52 +/- 13 years) with recurrent drug refractory atrioventricular nodal reentrant tachycardia underwent radiofrequency catheter ablation of slow-pathway as the first procedure. Maximal energy used was 28 +/- 8 W, mean time was 4.4 +/- 2.8 min, and a mean number of 13 +/- 9 discharges per patient. RESULTS: Of the 34 patients 14 were successfully treated (no slow-pathway conduction, no AV nodal reentrant echo complexes, no inducible tachycardia), 11 were considered as partially successful (no inducible tachycardia, with slow-pathway conduction or echoes) and 9 patients were unsuccessfully treated (all of them underwent fast-pathway ablation with a successful outcome). Eight recurrences were observed during a mean follow-up period of 7 +/- 4 months: One in a patient with previously successful ablation (remained asymptomatic while taking beta-blockers), 6 in patients with first procedure partially successful (all of them underwent effective second slow-pathway ablation) and 1 in a patient with an unsuccessful procedure that underwent fast pathway ablation. A repeated procedure was successful in ablating the slow pathway. None of our patients developed complete atrio-ventricular block. One patient developed cardiac tamponade that needed surgical drainage. At last follow-up all patients are free from tachycardias. CONCLUSION: Slow pathway ablation is an effective method of treatment in patients with atrio-ventricular nodal reentrant tachycardia. Long term success is related to complete abolition of slow pathway conduction.