Objectives: This study sought to determine the long-term follow-up, safety and efficacy of radiofrequency catheter ablation in patients with the permanent form of junctional reciprocating tachycardia. We assessed the reversibility of tachycardia-related left ventricular dysfunction and we detailed the location and electrophysiologic characteristics of these atrioventricular decremental pathways.
Background: Permanent junctional reciprocating tachycardia is an infrequent form on reciprocating tachycardia, commonly incessant and usually drug-refractory. The electrocardiographic hallmarks include an RP interval > PR with inverted P waves in leads II, III, aVF and V3-V6. During tachycardia, retrograde ventriculo-atrial conduction occurs over an accessory pathway with decremental conduction properties, located predominantly in the posteroseptal zone. It is known that long lasting and incessant tachycardia may result in tachycardia-related severe ventricular dysfunction, the so called tachycardiomyopathy.
Patients and methods: We included 24 patients (9 males, 15 females; mean age 42 +/- 22 years) with the diagnosis of permanent junctional reciprocating tachycardia at electrophysiologic study. Six patients had tachycardia-related left ventricular dysfunction. Radiofrequency energy was delivered at the site of earliest retrograde atrial activation during reciprocating tachycardia (n = 22) or ventricular pacing (n = 2). All patients were followed at the outpatient clinic and serial echocardiograms were performed in those who presented depressed left ventricular function.
Results: Radiofrequency catheter ablation was performed in 24 decremental accessory pathways. Earliest retrograde atrial activation was right posteroseptal in 22 patients (92%), right midseptal in 1 (4%) and right posterolateral in 1 (4%). Twenty-three accessory pathways were successfully ablated with a mean of 5 +/- 3 (median, 4) radiofrequency applications of a mean duration of 48 +/- 13 s. Only the midseptal accessory pathway could not be ablated. After a mean follow-up of 21 +/- 16 months (median, 15; range 2 to 64) 22 patients remain asymptomatic. There were recurrences in 4 patients after the initial successful ablation (three during the first month and one during the second month after the procedure), two were ablated in a second ablation procedure, one patient required a third procedure and one required a fourth. All patients with left ventricular dysfunction experienced an improvement after ablation. Mean preablation left ventricular ejection fraction in patients with tachycardiomyopathy was 28 +/- 6% (median, 27) and raised to 51 +/- 16% (median, 47) after ablation (p < 0.02).
Conclusions: Our study supports the concept that radiofrequency catheter ablation is a safe and useful treatment for patients with permanent junctional reciprocating tachycardia. Radiofrequency current should be the treatment of choice in these patients because this arrhythmia is usually drug-refractory. The majority of accessory pathways with decremental conduction properties are localized in the posteroseptal zone. Cessation of the arrhythmia after successful ablation results in recovery of left ventricular dysfunction.