BACKGROUND AND OBJECTIVES: Atrioventricular nodal reentrant tachycardia (AVNRT) is the most common regular supraventricular tachycardias in both the general population and elderly patients. The aim of this study is to investigate the clinical and electrophysiologic characteristics and efficacy of radiofrequency catheter ablation (RFCA) for treating AVNRT in the elderly. SUBJECTS AND METHODS: This study included 273 consecutive symptomatic AVNRT patients who underwent RFCA for the slow-pathway. The study population was divided into two groups: group I patients were younger than 65 years (n=227, average age: 44.6+/-12.9 years, male : female=89 : 138) and group II patients were older than 65 years (n=46, average age: 69.0+/-3.6, male : female=9 : 37). We compared the baseline clinical, electrocardiographic and electrophysiologic characteristics and the outcomes of RFCA between the two groups. RESULTS: The prevalence of a baseline prolonged PR interval (>200 ms) was not different between the 2 groups (1.8% vs. 6.5%, p>0.05). The baseline sinus cycle length, QT interval and AVNRT cycle length were significantly longer in group II than in group 1 (799.3+/-146.1 ms vs. 864.3+/-159.8 ms, 374.2+/-42.1 ms vs. 397.6+/-40.4 ms, 351.3+/-43.2 ms vs. 384.9+/-57.0 ms, respectively p<0.05). There was no difference in the rate of RFCA-related complications, including transient AV block. The incidence of AV block (> or =second degree) was not different between the two groups (4.0% vs. 6.5%, p>0.05). One patient in group I required permanent pacemaker implantation. CONCLUSION: RFCA in elderly patients is safe and effective as in younger patients. Therefore, performing RFCA for treating AVNRT should also be considered in the elderly patients.