This study sought to determine the long-term follow-up, safety, and efficacy of radiofrequency catheter ablation of patients with the permanent form of junctional reciprocating tachycardia (PJRT). We assessed the reversibility of tachycardia induced LV dysfunction and we detailed the location and electrophysiological characteristics of these retrograde atrioventricular decremental pathways. PJRT is an infrequent form of reciprocating tachycardia, commonly incessant, and usually drug refractory. The ECG hallmarks include an RP interval > PR with inverted P waves in leads II, III, a VF, and V3-V6. During tachycardia, retrograde VA conduction occurs over an accessory pathway with slow and decremental conduction properties, located predominantly in the posteroseptal zone. It is known that long-lasting and incessant tachycardia may result in tachycardia induced severe ventricular dysfunction. We included 36 patients (13 men, 23 women, mean +/- SD, aged 44 +/- 22 years) with the diagnosis of PJRT. Seven patients had tachycardia induced left ventricular dysfunction. Radiofrequency energy was delivered at the site of earliest retrograde atrial activation during ventricular pacing or during reciprocating tachycardia. All patients were followed at the outpatient clinic and serial echocardiograms were performed in those who presented with depressed LV function. Radiofrequency ablation was performed in 36 decremental accessory pathways. Earliest retrograde atrial activation was right posteroseptal in 32 patients (88%), right mid-septal in 2 (6%), right posterolateral in 1 (3%), and left anterolateral in 1 (3%). Thirty-five accessory pathways were successfully ablated with a mean of 5 +/- 3 applications. A mid-septal accessory pathway could not be ablated. After a mean follow-up of 21 +/- 16 months (range 1-64) 34 patients are asymptomatic. There were recurrences in 8 patients after the initial successful ablation (mean of 1.2 months), 5 were ablated in a second ablation procedure, 2 patients required a third procedure, and 1 patient required four ablation sessions. All patients with LV dysfunction experienced a remarkable improvement after ablation. Mean preablation LV ejection fraction in patients with tachycardiomyopathy was 28% +/- 6% and rose to 51% +/- 16% after ablation (P < 0.02). Our study supports the concept that radiofrequency catheter ablation is a safe and effective treatment for patients with PJRT. Radiofrequency ablation should be the treatment of choice in these patients because this arrhythmia is usually drug refractory. The majority of accessory pathways are located in the posteroseptal zone. Cessation of the arrhythmia after successful ablation results in recovery of LV dysfunction.