Radiofrequency transcatheter ablation is an effective and safe treatment for atrioventricular node reentry tachycardia. Slow pathway ablation is considered the ablative technique of choice, but when atrioventricular nodal reentrant tachycardia is associated with a prolonged PR interval at sinus rhythm, a higher risk of delayed atrioventricular (AV) block has been reported. Studies on the subject are few, enrolling low numbers of patients with variable selection criteria and producing different results. Hence, optimal ablation strategy remains controversial. The aim of this study is to review the available knowledge on the topic. Experience from our centers is also briefly reported.