Atrio-ventricular conduction following radiofrequency ablation for atrio-ventricular node reentry tachycardia in children

The study was designed to assess atrio-ventricular (AV) conduction with non-invasive methods at least 1 year after radiofrequency ablation (RFA) of the slow pathway for AV node reentry tachycardia. Medical records of all patients who underwent RFA before their 18th birthday were reviewed. Patients were brought back for clinical evaluation, an electrocardiogram, an exercise stress test, and ambulatory Holter monitoring. Radiofrequency ablation of the slow pathway above the ostium of the coronary sinus was done in 106 children. No procedure resulted in high degree AV block. Follow-up evaluation was possible in 67 patients (63% of the total cohort) who were brought back to the clinic 1-13.7 years, mean 4.7 +/- 3.0 years after the procedure. Dizzy spells were reported by 36% of examined patients and 2 patients reported syncope. PR intervals were normal in all but two patients when compared with published normal values. One patient presented with persistent, post-procedural first-degree AV block and another developed new onset, symptomatic second degree AV block 2 years after the procedure and required pacemaker implantation. Non-invasive testing showed normal PR intervals in a cohort of patients who underwent RFA of the slow pathway in childhood or adolescence. Late AV block occurred in one child. Clinical evaluation more than a year after the procedure is warranted in symptomatic patients.